Configuring QoS

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http:/​/​www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for Quality of Service

Before configuring standard QoS, you must have a thorough understanding of these items:

  • Standard QoS concepts.

  • Wireless concepts and network topologies.

  • Classic Cisco IOS QoS.

  • Modular QoS CLI (MQC).

  • Understanding of QoS implementation.

  • The types of applications used and the traffic patterns on your network.

  • Traffic characteristics and needs of your network. For example, is the traffic on your network bursty? Do you need to reserve bandwidth for voice and video streams?

  • Bandwidth requirements and speed of the network.

  • Location of congestion points in the network.

Restrictions for QoS on Wired Targets

A target is an entity where a policy is applied. You can apply a policy to either a wired or wireless target. A wired target can be either a port or VLAN. A wireless target can be either a port, radio, SSID, or client. Only port, SSID, and client policies are user configurable. Radio polices are not user configurable. Wireless QoS policies for port, radio, SSID, and client are applied in the downstream direction, and for upstream only SSID and client targets are supported. Downstream indicates that traffic is flowing from the switch to the wireless client. Upstream indicates that traffic is flowing from wireless client to the switch.

The following are restrictions for applying QoS features on the switch for the wired target:

  • A maximum of 8 queuing classes are supported on the switch port for the wired target.

  • A maximum of 63 policers are supported per policy on the wired port for the wired target.

  • No more than two levels are supported in a QoS hierarchy.

  • In a hierarchical policy, overlapping actions between parent and child are not allowed, except when a policy has the port shaper in the parent and queueing features in the child policy.

  • A QoS policy cannot be attached to any EtherChannel interface.

  • Policing in both the parent and child is not supported in a QoS hierarchy.

  • Marking in both the parent and child is not supported in a QoS hierarchy.

  • A mixture of queue limit and queue buffer in the same policy is not supported.


    Note

    The queue-limit percent is not supported on the switch because the queue-buffer command handles this functionality. Queue limit is only supported with the DSCP and CoS extensions.

  • With shaping, there is an IPG overhead of 20Bytes for every packet that is accounted internally in the hardware. Shaping accuracy will be effected by this, specially for packets of small size.

  • The classification sequence for all wired queuing-based policies should be the same across all wired upstream ports (10-Gigabit Ethernet), and the same for all downstream wired ports (1-Gigabit Ethernet).

  • Empty classes are not supported.

  • Class-maps with empty actions are not supported.

  • A maximum of 256 classes are supported per policy on the wired port for the wired target.

  • The actions under a policer within a policy map have the following restrictions:

    • The conform action must be transmit.

    • The exceed/violate action for markdown type can only be cos2cos, prec2prec, dscp2dscp.

    • The markdown types must be the same within a policy.

  • A port-level input marking policy takes precedence over an SVI policy; however, if no port policy is configured, the SVI policy takes precedence. For a port policy to take precedence, define a port-level policy; so that the SVI policy is overwritten.

  • Classification counters have the following specific restrictions:

    • Classification counters count packets instead of bytes.

    • Filter-based classification counters are not supported

    • Only QoS configurations with marking or policing trigger the classification counter.

    • The classification counter is not port based. This means that the classification counter aggregates all packets belonging to the same class of the same policy which attach to different interfaces.

    • As long as there is policing or marking action in the policy, the class-default will have classification counters.

    • When there are multiple match statements in a class, then the classification counter only shows the traffic counter for one of the match statements.

  • Table maps have the following specific restrictions:

    • Only one table map for policing exceeding the markdown and one table map for policing violating the markdown per direction per target is supported.

    • Table maps must be configured under the class-default; table maps are unsupported for a user-defined class.

  • Hierarchical policies are required for the following:

    • Port-shapers

    • Aggregate policers

    • PV policy

    • Parent shaping and child marking/policing

  • For ports with wired targets, these are the only supported hierarchical policies:

    • Police chaining in the same policy is unsupported, except for wireless client.

    • Hierarchical queueing is unsupported in the same policy (port shaper is the exception).

    • In a parent class, all filters must have the same type. The child filter type must match the parent filter type with the following exceptions:

      • If the parent class is configured to match IP, then the child class can be configured to match the ACL.

      • If the parent class is configured to match CoS, then the child class can be configured to match the ACL.

  • The trust device device_type command available in interface configuration mode is a stand-alone command on the switch. When using this command in an AutoQoS configuration, if the connected peer device is not a corresponding device (defined as a device matching your trust policy), both CoS and DSCP values are set to "0" and any input policy will not take effect. If the connected peer device is a corresponding device, input policy will take effect.

The following are restrictions for applying QoS features on the VLAN to the wired target:

  • For a flat or nonhierarchical policy, only marking or a table map is supported.

The following are restrictions and considerations for applying QoS features on EtherChannel and channel member interfaces:

  • QoS is not supported on an EtherChannel interface.

  • QoS is supported on EtherChannel member interfaces in both ingress and egression directions. All EtherChannel members must have the same QoS policy applied. If the QoS policy is not the same, each individual policy on the different link acts independently.

  • On attaching a service policy to channel members, the following warning message appears to remind the user to make sure the same policy is attached to all ports in the EtherChannel: ' Warning: add service policy will cause inconsistency with port xxx in ether channel xxx. '.

  • Auto QoS is not supported on EtherChannel members.


Note
On attaching a service policy to an EtherChannel, the following message appears on the console: ' Warning: add service policy will cause inconsistency with port xxx in ether channel xxx. '. This warning message should be expected. This warning message is a reminder to attach the same policy to other ports in the same EtherChannel. The same message will be seen during boot up. This message does not mean there is a discrepancy between the EtherChannel member ports.
Related References
Restrictions for QoS on Wireless Targets

Information About QoS

QoS Overview

By configuring the quality of service (QoS), you can provide preferential treatment to specific types of traffic at the expense of other traffic types. Without QoS, the switch offers best-effort service to each packet, regardless of the packet contents or size. The switch sends the packets without any assurance of reliability, delay bounds, or throughput.

The following are specific features provided by QoS:

  • Low latency

  • Bandwidth guarantee

  • Buffering capabilities and dropping disciplines

  • Traffic policing

  • Enables the changing of the attribute of the frame or packet header

  • Relative services

Modular QoS Command-Line Interface

With the switch, QoS features are enabled through the Modular QoS command-line interface (MQC). The MQC is a command-line interface (CLI) structure that allows you to create traffic policies and attach these policies to interfaces. A traffic policy contains a traffic class and one or more QoS features. A traffic class is used to classify traffic, while the QoS features in the traffic policy determine how to treat the classified traffic. One of the main goals of MQC is to provide a platform-independent interface for configuring QoS across Cisco platforms.

QoS and IPv6 for Wireless

The switch supports QoS for both IPv4 and IPv6 traffic, and client policies can now have IPv4 and IPv6 filters.

Supported QoS Features for Wired Access

The following table describes the supported QoS features for wired access.

Table 1 Supported QoS Features for Wired Access

Feature

Description

Supported targets

  • Gigabit Ethernet

  • 10-Gigabit Ethernet

  • VLAN

Configuration sequence

QoS policy installed using the service-policy command.

Supported number of queues at port level

Up to 8 queues supported on a port.

No Approximate Fair Dropping or Discard (AFD) support for wired targets.

Supported classification mechanism

  • DSCP

  • IP precedence

  • CoS

  • QoS-group

  • ACL membership including:

    • IPv4 ACLs

    • IPv6 ACLS

    • MAC ACLs

Hierarchical QoS

The switch supports hierarchical QoS (HQoS). HQoS allows you to perform:

  • Hierarchical classification— Traffic classification is based upon other classes.

  • Hierarchical policing—The process of having the policing configuration at multiple levels in a hierarchical policy.

  • Hierarchical shaping—Shaping can also be configured at multiple levels in the hierarchy.


    Note

    Hierarchical shaping is only supported for the port shaper, where for the parent you only have a configuration for the class default, and the only action for the class default is shaping.

Related References
Examples: Hierarchical Classification

QoS Implementation

Typically, networks operate on a best-effort delivery basis, which means that all traffic has equal priority and an equal chance of being delivered in a timely manner. When congestion occurs, all traffic has an equal chance of being dropped.

When you configure the QoS feature, you can select specific network traffic, prioritize it according to its relative importance, and use congestion-management and congestion-avoidance techniques to provide preferential treatment. Implementing QoS in your network makes network performance more predictable and bandwidth utilization more effective.

The QoS implementation is based on the Differentiated Services (Diff-Serv) architecture, a standard from the Internet Engineering Task Force (IETF). This architecture specifies that each packet is classified upon entry into the network.

The classification is carried in the IP packet header, using 6 bits from the deprecated IP type of service (ToS) field to carry the classification (class) information. Classification can also be carried in the Layer 2 frame.

Figure 1. QoS Classification Layers in Frames and Packets. The special bits in the Layer 2 frame or a Layer 3 packet are shown in the following figure:

Layer 2 Frame Prioritization Bits

Layer 2 Inter-Switch Link (ISL) frame headers have a 1-byte User field that carries an IEEE 802.1p class of service (CoS) value in the three least-significant bits. On ports configured as Layer 2 ISL trunks, all traffic is in ISL frames.

Layer 2 802.1Q frame headers have a 2-byte Tag Control Information field that carries the CoS value in the three most-significant bits, which are called the User Priority bits. On ports configured as Layer 2 802.1Q trunks, all traffic is in 802.1Q frames except for traffic in the native VLAN.

Other frame types cannot carry Layer 2 CoS values.

Layer 2 CoS values range from 0 for low priority to 7 for high priority.

Layer 3 Packet Prioritization Bits

Layer 3 IP packets can carry either an IP precedence value or a Differentiated Services Code Point (DSCP) value. QoS supports the use of either value because DSCP values are backward-compatible with IP precedence values.

IP precedence values range from 0 to 7. DSCP values range from 0 to 63.

End-to-End QoS Solution Using Classification

All switches and routers that access the Internet rely on the class information to provide the same forwarding treatment to packets with the same class information and different treatment to packets with different class information. The class information in the packet can be assigned by end hosts or by switches or routers along the way, based on a configured policy, detailed examination of the packet, or both. Detailed examination of the packet is expected to occur closer to the edge of the network, so that the core switches and routers are not overloaded with this task.

Switches and routers along the path can use the class information to limit the amount of resources allocated per traffic class. The behavior of an individual device when handling traffic in the Diff-Serv architecture is called per-hop behavior. If all devices along a path provide a consistent per-hop behavior, you can construct an end-to-end QoS solution.

Implementing QoS in your network can be a simple task or complex task and depends on the QoS features offered by your internetworking devices, the traffic types and patterns in your network, and the granularity of control that you need over incoming and outgoing traffic.

Packet Classification

Packet classification is the process of identifying a packet as belonging to one of several classes in a defined policy, based on certain criteria. The Modular QoS CLI (MQC) is a policy-class based language. The policy class language is used to define the following:

  • Class-map template with one or several match criteria

  • Policy-map template with one or several classes associated to the policy map

The policy map template is then associated to one or several interfaces on the switch.

Packet classification is the process of identifying a packet as belonging to one of the classes defined in the policy map. The process of classification will exit when the packet being processed matches a specific filter in a class. This is referred to as first-match exit. If a packet matches multiple classes in a policy, irrespective of the order of classes in the policy map, it would still exit the classification process after matching the first class.

If a packet does not match any of the classes in the policy, it would be classified into the default class in the policy. Every policy map has a default class, which is a system-defined class to match packets that do not match any of the user-defined classes.

Packet classification can be categorized into the following types:

  • Classification based on information that is propagated with the packet

  • Classification based on information that is switch specific

  • Hierarchical classification

Classification Based on Information That is Propagated with the Packet

Classification that is based on information that is part of the packet and propagated either end-to-end or between hops, typically includes the following:

  • Classification based on Layer 3 or 4 headers

  • Classification based on Layer 2 information

Classification Based on Layer 3 or Layer 4 Header

This is the most common deployment scenario. Numerous fields in the Layer 3 and Layer 4 headers can be used for packet classification.

At the most granular level, this classification methodology can be used to match an entire flow. For this deployment type, an access control list (ACLs) can be used. ACLs can also be used to match based on various subsets of the flow (for example, source IP address only, or destination IP address only, or a combination of both).

Classification can also be done based on the precedence or DSCP values in the IP header. The IP precedence field is used to indicate the relative priority with which a particular packet needs to be handled. It is made up of three bits in the IP header's type of service (ToS) byte.

The following table shows the different IP precedence bit values and their names.
Note   

IP precedence is not supported for wireless QoS.



Table 2 IP Precedence Values and Names

IP Precedence Value

IP Precedence Bits

IP Precedence Names

0

000

Routine

1

001

Priority

2

010

Immediate

3

011

Flash

4

100

Flash Override

5

101

Critical

6

110

Internetwork control

7

111

Network control

Note

All routing control traffic in the network uses IP precedence value 6 by default. IP precedence value 7 also is reserved for network control traffic. Therefore, the use of IP precedence values 6 and 7 is not recommended for user traffic.

The DSCP field is made up of 6 bits in the IP header and is being standardized by the Internet Engineering Task Force (IETF) Differentiated Services Working Group. The original ToS byte contained the DSCP bits has been renamed the DSCP byte. The DSCP field is part of the IP header, similar to IP precedence. The DSCP field is a super set of the IP precedence field. Therefore, the DSCP field is used and is set in ways similar to what was described with respect to IP precedence.


Note

The DSCP field definition is backward-compatible with the IP precedence values.

Classification Based on Layer 2 Header

A variety of methods can be used to perform classification based on the Layer 2 header information. The most common methods include the following:

  • MAC address-based classification (only for access groups)—Classification is based upon the source MAC address (for policies in the input direction) and destination MAC address (for policies in the output direction).

  • Class-of-Service—Classification is based on the 3 bits in the Layer 2 header based on the IEEE 802.1p standard. This usually maps to the ToS byte in the IP header.

  • VLAN ID—Classification is based on the VLAN ID of the packet.


Note

Some of these fields in the Layer 2 header can also be set using a policy.

Classification Based on Information that is Device Specific (QoS Groups)

The switch also provides classification mechanisms that are available where classification is not based on information in the packet header or payload.

At times you might be required to aggregate traffic coming from multiple input interfaces into a specific class in the output interface. For example, multiple customer edge routers might be going into the same access switch on different interfaces. The service provider might want to police all the aggregate voice traffic going into the core to a specific rate. However, the voice traffic coming in from the different customers could have a different ToS settings. QoS group-based classification is a feature that is useful in these scenarios.

Policies configured on the input interfaces set the QoS group to a specific value, which can then be used to classify packets in the policy enabled on output interface.

The QoS group is a field in the packet data structure internal to the switch. It is important to note that a QoS group is an internal label to the switch and is not part of the packet header.

Hierarchical Classification

The switch permits you to perform a classification based on other classes. Typically, this action may be required when there is a need to combine the classification mechanisms (that is, filters) from two or more classes into a single class map.

QoS Wired Model

To implement QoS, the switch must perform the following tasks:

  • Traffic classification—Distinguishes packets or flows from one another.

  • Traffic marking and policing—Assigns a label to indicate the given quality of service as the packets move through the switch, and then make the packets comply with the configured resource usage limits.

  • Queuing and scheduling—Provides different treatment in all situations where resource contention exists.

  • Shaping—Ensures that traffic sent from the switch meets a specific traffic profile.

Ingress Port Activity

The following activities occur at the ingress port of the switch:

  • Classification—Classifying a distinct path for a packet by associating it with a QoS label. For example, the switch maps the CoS or DSCP in the packet to a QoS label to distinguish one type of traffic from another. The QoS label that is generated identifies all future QoS actions to be performed on this packet.

  • Policing—Policing determines whether a packet is in or out of profile by comparing the rate of the incoming traffic to the configured policer. The policer limits the bandwidth consumed by a flow of traffic. The result is passed to the marker.

  • Marking—Marking evaluates the policer and configuration information for the action to be taken when a packet is out of profile and determines what to do with the packet (pass through a packet without modification, mark down the QoS label in the packet, or drop the packet).


Note

Applying polices on the wireless ingress port is not supported on the switch.

Egress Port Activity

The following activities occur at the egress port of the switch:

  • Policing—Policing determines whether a packet is in or out of profile by comparing the rate of the incoming traffic to the configured policer. The policer limits the bandwidth consumed by a flow of traffic. The result is passed to the marker.

  • Marking—Marking evaluates the policer and configuration information for the action to be taken when a packet is out of profile and determines what to do with the packet (pass through a packet without modification, mark down the QoS label in the packet, or drop the packet).

  • Queueing—Queueing evaluates the QoS packet label and the corresponding DSCP or CoS value before selecting which of the egress queues to use. Because congestion can occur when multiple ingress ports simultaneously send data to an egress port, Weighted Tail Drop (WTD) differentiates traffic classes and subjects the packets to different thresholds based on the QoS label. If the threshold is exceeded, the packet is dropped.

Classification

Classification is the process of distinguishing one kind of traffic from another by examining the fields in the packet. Classification is enabled only if QoS is enabled on the switch. By default, QoS is enabled on the switch.

During classification, the switch performs a lookup and assigns a QoS label to the packet. The QoS label identifies all QoS actions to be performed on the packet and from which queue the packet is sent.

Access Control Lists

You can use IP standard, IP extended, or Layer 2 MAC ACLs to define a group of packets with the same characteristics (class). You can also classify IP traffic based on IPv6 ACLs.

In the QoS context, the permit and deny actions in the access control entries (ACEs) have different meanings from security ACLs:

  • If a match with a permit action is encountered (first-match principle), the specified QoS-related action is taken.

  • If a match with a deny action is encountered, the ACL being processed is skipped, and the next ACL is processed.

  • If no match with a permit action is encountered and all the ACEs have been examined, no QoS processing occurs on the packet, and the switch offers best-effort service to the packet.

  • If multiple ACLs are configured on a port, the lookup stops after the packet matches the first ACL with a permit action, and QoS processing begins.


    Note

    When creating an access list, note that by default the end of the access list contains an implicit deny statement for everything if it did not find a match before reaching the end.

After a traffic class has been defined with the ACL, you can attach a policy to it. A policy might contain multiple classes with actions specified for each one of them. A policy might include commands to classify the class as a particular aggregate (for example, assign a DSCP) or rate-limit the class. This policy is then attached to a particular port on which it becomes effective.

You implement IP ACLs to classify IP traffic by using the access-list global configuration command; you implement Layer 2 MAC ACLs to classify non-IP traffic by using the mac access-list extended global configuration command.

Class Maps

A class map is a mechanism that you use to name a specific traffic flow (or class) and isolate it from all other traffic. The class map defines the criteria used to match against a specific traffic flow to further classify it. The criteria can include matching the access group defined by the ACL or matching a specific list of DSCP or IP precedence values. If you have more than one type of traffic that you want to classify, you can create another class map and use a different name. After a packet is matched against the class-map criteria, you further classify it through the use of a policy map.

You create a class map by using the class-map global configuration command or the class policy-map configuration command. You should use the class-map command when the map is shared among many ports. When you enter the class-map command, the switch enters the class-map configuration mode. In this mode, you define the match criterion for the traffic by using the match class-map configuration command.

You can create a default class by using the class class-default policy-map configuration command. The default class is system-defined and cannot be configured. Unclassified traffic (traffic that does not meet the match criteria specified in the traffic classes) is treated as default traffic.

Related Tasks
Creating a Traffic Class
Related References
Examples: Classification by Access Control Lists

Policy Maps

A policy map specifies which traffic class to act on. Actions can include the following:

  • Setting a specific DSCP or IP precedence value in the traffic class

  • Setting a CoS value in the traffic class

  • Setting a QoS group

  • Setting a wireless LAN (WLAN) value in the traffic class

  • Specifying the traffic bandwidth limitations and the action to take when the traffic is out of profile

Before a policy map can be effective, you must attach it to a port.

You create and name a policy map using the policy-map global configuration command. When you enter this command, the switch enters the policy-map configuration mode. In this mode, you specify the actions to take on a specific traffic class by using the class or set policy-map configuration and policy-map class configuration commands.

The policy map can also be configured using the police and bandwidth policy-map class configuration commands, which define the policer, the bandwidth limitations of the traffic, and the action to take if the limits are exceeded. In addition, the policy-map can further be configured using the priority policy-map class configuration command, to schedule priority for the class or the queueing policy-map class configuration commands, queue-buffers and queue-limit.

To enable the policy map, you attach it to a port by using the service-policy interface configuration command.


Note
You cannot configure both priority and set for a policy map. If both these commands are configured for a policy map, and when the policy map is applied to an interface, error messages are displayed. The following example shows this restriction: 
Switch# configure terminal
Switch(config)# class-map cmap
Switch(config-cmap)# exit
Switch(config)# class-map classmap1
Switch(config-cmap)# exit
Switch(config)# policy-map pmap
Switch(config-pmap)# class cmap
Switch(config-pmap-c)# priority
Switch(config-pmap-c)# exit
Switch(config-pmap)# class classmap1
Switch(config-pmap-c)# set
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config)# interface gigabitethernet 0/1/1
Switch(config-if)# service-policy output pmap

Non-queuing action only is unsupported in a queuing policy!!!
%QOS-6-POLICY_INST_FAILED:
Service policy installation failed
Related Tasks
Creating a Traffic Policy

Policy Map on Physical Port

You can configure a nonhierarchical policy map on a physical port that specifies which traffic class to act on. Actions can include setting a specific DSCP or IP precedence value in the traffic class, specifying the traffic bandwidth limitations for each matched traffic class (policer), and taking action when the traffic is out of profile (marking).

A policy map also has these characteristics:

  • A policy map can contain multiple class statements, each with different match criteria and policers.

  • A policy map can contain a predefined default traffic class explicitly placed at the end of the map.

    When you configure a default traffic class by using the class class-default policy-map configuration command, unclassified traffic (traffic that does not meet the match criteria specified in the traffic classes) is treated as the default traffic class (class-default).

  • A separate policy-map class can exist for each type of traffic received through a port.

Related Tasks
Attaching a Traffic Policy to an Interface

Policy Map on VLANs

The switch supports a VLAN QoS feature that allows the user to perform QoS treatment at the VLAN level (classification and QoS actions) using the incoming frame’s VLAN information. In VLAN-based QoS, a service policy is applied to an SVI interface. All physical interfaces belonging to a VLAN policy map then need to be programmed to refer to the VLAN-based policy maps instead of the port-based policy map.

Although the policy map is applied to the VLAN SVI, any policing (rate-limiting) action can only be performed on a per-port basis. You cannot configure the policer to take account of the sum of traffic from a number of physical ports. Each port needs to have a separate policer governing the traffic coming into that port.

Related Tasks
Classifying, Policing, and Marking Traffic on SVIs by Using Policy Maps
Related References
Examples: Policer VLAN Configuration

Policing

After a packet is classified and has a DSCP-based, CoS-based, or QoS-group label assigned to it, the policing and marking process can begin.

Policing involves creating a policer that specifies the bandwidth limits for the traffic. Packets that exceed the limits are out of profile or nonconforming. Each policer decides on a packet-by-packet basis whether the packet is in or out of profile and specifies the actions on the packet. These actions, carried out by the marker, include passing through the packet without modification, dropping the packet, or modifying (marking down) the assigned DSCP or CoS value of the packet and allowing the packet to pass through.

To avoid out-of-order packets, both conform and nonconforming traffic typically exit the same queue.


Note

All traffic, regardless of whether it is bridged or routed, is subjected to a policer, if one is configured. As a result, bridged packets might be dropped or might have their DSCP or CoS fields modified when they are policed and marked.

You can only configure policing on a physical port.

After you configure the policy map and policing actions, attach the policy to an ingress port or SVI by using the service-policy interface configuration command.

Related Tasks
Configuring Police
Related References
Examples: Policing Action Configuration

Token-Bucket Algorithm

Policing uses a token-bucket algorithm. As each frame is received by the switch, a token is added to the bucket. The bucket has a hole in it and leaks at a rate that you specify as the average traffic rate in bits per second. Each time a token is added to the bucket, the switch verifies that there is enough room in the bucket. If there is not enough room, the packet is marked as nonconforming, and the specified policer action is taken (dropped or marked down).

How quickly the bucket fills is a function of the bucket depth (burst-byte), the rate at which the tokens are removed (rate-bps), and the duration of the burst above the average rate. The size of the bucket imposes an upper limit on the burst length and limits the number of frames that can be transmitted back-to-back. If the burst is short, the bucket does not overflow, and no action is taken against the traffic flow. However, if a burst is long and at a higher rate, the bucket overflows, and the policing actions are taken against the frames in that burst.

You configure the bucket depth (the maximum burst that is tolerated before the bucket overflows) by using the burst-byte option of the police policy-map class configuration command. You configure how fast (the average rate) that the tokens are removed from the bucket by using the rate option of the police policy-map class configuration command.

Related Tasks
Configuring Police
Related References
Examples: Policing Units

Marking

Marking is used to convey specific information to a downstream device in the network, or to carry information from one interface in a switch to another.

Marking can be used to set certain field/bits in the packet headers, or marking can also be used to set certain fields in the packet structure that is internal to the switch. Additionally, the marking feature can be used to define mapping between fields. The following marking methods are available for QoS:

  • Packet header

  • Device (switch) specific information

  • Table maps

Packet Header Marking

Marking on fields in the packet header can be classified into two general categories:

  • IPv4/v6 header bit marking

  • Layer 2 header bit marking

The marking feature at the IP level is used to set the precedence or the DSCP in the IP header to a specific value to get a specific per-hop behavior at the downstream device (switch or router), or it can also be used to aggregate traffic from different input interfaces into a single class in the output interface. The functionality is currently supported on both the IPv4 and IPv6 headers.

Marking in the Layer 2 headers is typically used to influence dropping behavior in the downstream devices (switch or router). It works in tandem with the match on the Layer 2 headers. The bits in the Layer 2 header that can be set using a policy map are class of service.

Switch Specific Information Marking

This form of marking includes marking of fields in the packet data structure that are not part of the packets header, so that the marking can be used later in the data path. This is not propagated between the switches. Marking of QoS-group falls into this category. This form of marking is only supported in policies that are enabled on the input interfaces. The corresponding matching mechanism can be enabled on the output interfaces on the same switch and an appropriate QoS action can be applied.

Table Map Marking

Table map marking enables the mapping and conversion from one field to another using a conversion table. This conversion table is called a table map.

Depending upon the table map attached to an interface, CoS, DSCP, and UP values (UP specific to wireless packets) of the packet are rewritten. The switch allows configuring both ingress table map policies and egress table map policies.


Note

The switch stack supports a total of 14 table maps. Only one table map is supported per wired port, per direction.

As an example, a table map can be used to map the Layer 2 CoS setting to a precedence value in Layer 3. This feature enables combining multiple set commands into a single table, which indicates the method to perform the mapping. This table can be referenced in multiple policies, or multiple times in the same policy.

The following table shows the currently supported forms of mapping:

Table 3 Packet-Marking Types Used for Establishing a To-From Relationship

The To Packet-Marking Type

The From Packet-Marking Type

Precedence

CoS

Precedence

QoS Group

DSCP

CoS

DSCP

QoS Group

CoS

Precedence

CoS

DSCP

QoS Group

Precedence

QoS Group

DSCP

A table map-based policy supports the following capabilities:

  • Mutation—You can have a table map that maps from one DSCP value set to another DSCP value set, and this can be attached to an egress port.

  • Rewrite—Packets coming in are rewritten depending upon the configured table map.

  • Mapping—Table map based policies can be used instead of set policies.

The following steps are required for table map marking:

  1. Define the table map—Use the table-map global configuration command to map the values. The table does not know of the policies or classes within which it will be used. The default command in the table map is used to indicate the value to be copied into the to field when there is no matching from field.

  2. Define the policy map—You must define the policy map where the table map will be used.

  3. Associate the policy to an interface.


Note

A table map policy on an input port changes the trust setting of that port to the from type of qos-marking.

Related Tasks
Configuring Table Maps
Related References
Examples: Table Map Marking Configuration

Traffic Conditioning

To support QoS in a network, traffic entering the service provider network needs to be policed on the network boundary routers to ensure that the traffic rate stays within the service limit. Even if a few routers at the network boundary start sending more traffic than what the network core is provisioned to handle, the increased traffic load leads to network congestion. The degraded performance in the network makes it difficult to deliver QoS for all the network traffic.

Traffic policing functions (using the police feature) and shaping functions (using the traffic shaping feature) manage the traffic rate, but differ in how they treat traffic when tokens are exhausted. The concept of tokens comes from the token bucket scheme, a traffic metering function.


Note

When running QoS tests on network traffic, you may see different results for the shaper and policing data. Network traffic data from shaping provides more accurate results.

This table compares the policing and shaping functions.

Table 4 Comparison Between Policing and Shaping Functions

Policing Function

Shaping Function

Sends conforming traffic up to the line rate and allows bursts.

Smooths traffic and sends it out at a constant rate.

When tokens are exhausted, action is taken immediately.

When tokens are exhausted, it buffers packets and sends them out later, when tokens are available. A class with shaping has a queue associated with it which will be used to buffer the packets.

Policing has multiple units of configuration – in bits per second, packets per second and cells per second.

Shaping has only one unit of configuration - in bits per second.

Policing has multiple possible actions associated with an event, marking and dropping being example of such actions.

Shaping does not have the provision to mark packets that do not meet the profile.

Works for both input and output traffic.

Implemented for output traffic only.

Transmission Control Protocol (TCP) detects the line at line speed but adapts to the configured rate when a packet drop occurs by lowering its window size.

TCP can detect that it has a lower speed line and adapt its retransmission timer accordingly. This results in less scope of retransmissions and is TCP-friendly.

Policing

The QoS policing feature is used to impose a maximum rate on a traffic class. The QoS policing feature can also be used with the priority feature to restrict priority traffic. If the rate is exceeded, then a specific action is taken as soon as the event occurs. The rate (committed information rate [CIR] and peak information rate [PIR] ) and the burst parameters (conformed burst size [ Bc ] and extended burst size [Be] ) are all configured in bytes per second.

The following policing forms or policers are supported for QoS:

  • Single-rate two-color policing

  • Dual-rate three-color policing


Note

Single-rate three-color policing is not supported.

Single-Rate Two-Color Policing

Single-rate two-color policer is the mode in which you configure only a CIR and a Bc.

The Bc is an optional parameter, and if it is not specified it is computed by default. In this mode, when an incoming packet has enough tokens available, the packet is considered to be conforming. If at the time of packet arrival, enough tokens are not available within the bounds of Bc, the packet is considered to have exceeded the configured rate.


Note

For information about the token-bucket algorithm, see Token-Bucket Algorithm.

Related Tasks
Configuring Police
Related References
Examples: Single-Rate Two-Color Policing Configuration

Dual-Rate Three-Color Policing

With the dual rate policer, the switch supports only color-blind mode. In this mode, you configure a committed information rate (CIR) and a peak information rate (PIR). As the name suggests, there are two token buckets in this case, one for the peak rate, and one for the conformed rate.


Note

For information about the token-bucket algorithm, see Token-Bucket Algorithm.

In the color-blind mode, the incoming packet is first checked against the peak rate bucket. If there are not enough tokens available, the packet is said to violate the rate. If there are enough tokens available, then the tokens in the conformed rate buckets are checked to determine if there are enough tokens available. The tokens in the peak rate bucket are decremented by the size of the packet. If it does not have enough tokens available, the packet is said to have exceeded the configured rate. If there are enough tokens available, then the packet is said to conform, and the tokens in both the buckets are decremented by the size of the packet.

The rate at which tokens are replenished depends on the packet arrival. Assume that a packet comes in at time T1 and the next one comes in at time T2. The time interval between T1 and T2 determines the number of tokens that need to be added to the token bucket. This is calculated as:

Time interval between packets (T2-T1) * CIR)/8 bytes

Related Tasks
Configuring Police
Related References
Examples: Dual-Rate Three-Color Policing Configuration

Shaping

Shaping is the process of imposing a maximum rate of traffic, while regulating the traffic rate in such a way that the downstream switches and routers are not subjected to congestion. Shaping in the most common form is used to limit the traffic sent from a physical or logical interface.

Shaping has a buffer associated with it that ensures that packets which do not have enough tokens are buffered as opposed to being immediately dropped. The number of buffers available to the subset of traffic being shaped is limited and is computed based on a variety of factors. The number of buffers available can also be tuned using specific QoS commands. Packets are buffered as buffers are available, beyond which they are dropped.

Class-Based Traffic Shaping

The switch uses class-based traffic shaping. This shaping feature is enabled on a class in a policy that is associated to an interface. A class that has shaping configured is allocated a number of buffers to hold the packets that do not have tokens. The buffered packets are sent out from the class using FIFO. In the most common form of usage, class-based shaping is used to impose a maximum rate for an physical interface or logical interface as a whole. The following shaping forms are supported in a class:

  • Average rate shaping

  • Hierarchical shaping

Shaping is implemented using a token bucket. The values of CIR, Bc and Be determine the rate at which the packets are sent out and the rate at which the tokens are replenished.


Note

For information about the token-bucket algorithm, see Token-Bucket Algorithm.

Average Rate Shaping

You use the shape average policy-map class command to configure average rate shaping.

This command configures a maximum bandwidth for a particular class. The queue bandwidth is restricted to this value even though the port has more bandwidth available. The switch supports configuring shape average by either a percentage or by a target bit rate value.

Related Tasks
Configuring Shaping
Related References
Examples: Average Rate Shaping Configuration
Hierarchical Shaping

Shaping can also be configured at multiple levels in a hierarchy. This is accomplished by creating a parent policy with shaping configured, and then attaching child policies with additional shaping configurations to the parent policy.

There are two supported types of hierarchical shaping:

  • Port shaper

  • User-configured shaping

The port shaper uses the class default and the only action permitted in the parent is shaping. The queueing action is in the child with the port shaper. With the user configured shaping, you cannot have queueing action in the child.

Related Tasks
Configuring Shaping

Queueing and Scheduling

The switch uses both queueing and scheduling to help prevent traffic congestion. The switch supports the following queueing and scheduling features:

  • Bandwidth

  • Weighted Tail Drop

  • Priority queues

  • Queue buffers

When you define a queuing policy on a port, control packets are mapped to the best priority queue with the highest threshold. Control packets queue mapping works differently in the following scenarios:

  • Without a quality of service (QoS) policy—If no QoS policy is configured, control packets with DSCP values 16, 24, 48, and 56 are mapped to queue 0 with the highest threshold of threshold2.

  • With an user-defined policy—An user-defined queuing policy configured on egress ports can affect the default priority queue setting on control packets.

    Control traffic is redirected to the best queue based on the following rules:

    1. If defined in a user policy, the highest- level priority queue is always chosen as the best queue.

    2. In the absence of a priority queue, Cisco IOS software selects queue 0 as the best queue. When the software selects queue 0 as the best queue, you must define the highest bandwidth to this queue to get the best QoS treatment to the control plane traffic.

    3. If thresholds are not configured on the best queue, Cisco IOS software assigns control packets with Differentiated Services Code Point (DSCP) values 16, 24, 48, and 56 are mapped to threshold2 and reassigns the rest of the control traffic in the best queue to threshold1.

    If a policy is not configured explicitly for control traffic, the Cisco IOS software maps all unmatched control traffic to the best queue with threshold2, and the matched control traffic is mapped to the queue as configured in the policy.


    Note

    To provide proper QoS for Layer 3 packets, you must ensure that packets are explicitly classified into appropriate queues. When the software detects DSCP values in the default queue, then it automatically reassigns this queue as the best queue.

Bandwidth

The switch supports the following bandwidth configurations:

  • Bandwidth percent

  • Bandwidth remaining ratio

Related Tasks
Configuring Bandwidth

Bandwidth Percent

You can use the bandwidth percent policy-map class command to allocate a minimum bandwidth to a particular class. The total sum cannot exceed 100 percent and in case the total sum is less than 100 percent, then the rest of the bandwidth is divided equally among all bandwidth queues.


Note

A queue can oversubscribe bandwidth in case the other queues do not utilize the entire port bandwidth.

You cannot mix bandwidth types on a policy map. For example, you cannot configure bandwidth in a single policy map using both a bandwidth percent and in kilobits per second.

Bandwidth Remaining Ratio

You use the bandwidth remaining ratio policy-map class command to create a ratio for sharing unused bandwidth in specified queues. Any unused bandwidth will be used by these specific queues in the ratio that is specified by the configuration. Use this command when the priority command is also used for certain queues in the policy.

When you assign ratios, the queues will be assigned certain weights which are inline with these ratios.

You can specify ratios using a range from 0 to 100. For example, you can configure a bandwidth remaining ration of 2 on one class, and another queue with a bandwidth remaining ratio of 4 on another class. The bandwidth remaining ratio of 4 will be scheduled twice as often as the bandwidth remaining ratio of 2.

The total bandwidth ratio allocation for the policy can exceed 100. For example, you can configure a queue with a bandwidth remaining ratio of 50, and another queue with a bandwidth remaining ratio of 100.

Weighted Tail Drop

The switch egress queues use an enhanced version of the tail-drop congestion-avoidance mechanism called weighted tail drop (WTD). WTD is implemented on queues to manage the queue lengths and to provide drop precedences for different traffic classifications.

As a frame is enqueued to a particular queue, WTD uses the frame’s assigned QoS label to subject it to different thresholds. If the threshold is exceeded for that QoS label (the space available in the destination queue is less than the size of the frame), the switch drops the frame.

Each queue has three configurable threshold values. The QoS label determines which of the three threshold values is subjected to the frame.

Figure 2. WTD and Queue Operation. The following figure shows an example of WTD operating on a queue whose size is 1000 frames. Three drop percentages are configured: 40 percent (400 frames), 60 percent (600 frames), and 100 percent (1000 frames). These percentages indicate that up to 400 frames can be queued at the 40-percent threshold, up to 600 frames at the 60-percent threshold, and up to 1000 frames at the 100-percent threshold.

In the example, CoS value 6 has a greater importance than the other CoS values, and is assigned to the 100-percent drop threshold (queue-full state). CoS values 4 is assigned to the 60-percent threshold, and CoS values 3 is assigned to the 40-percent threshold. All of these threshold values are assigned using the queue-limit cos command.

Assuming the queue is already filled with 600 frames, and a new frame arrives. It contains CoS value 4 and is subjected to the 60-percent threshold. If this frame is added to the queue, the threshold will be exceeded, so the switch drops it.

Related Tasks
Configuring Queue Limits
Related References
Examples: Queue-limit Configuration

Weighted Tail Drop Default Values

The following are the Weighted Tail Drop (WTD) default values and the rules for configuring WTD threshold values.

  • If you configure less than three queue-limit percentages for WTD, then WTD default values are assigned to these thresholds.

    The following are the WTD threshold default values:

    Table 5 WTD Threshold Default Values

    Threshold

    Default Value Percentage

    0

    80

    1

    90

    2

    400

  • If 3 different WTD thresholds are configured, then the queues are programmed as configured.

  • If 2 WTD thresholds are configured, then the maximum value percentage will be 400.

  • If a WTD single threshold is configured as x, then the maximum value percentage will be 400.

    • If the value of x is less than 90, then threshold1=90 and threshold 0= x.

    • If the value of x equals 90, then threshold1=90, threshold 0=80.

    • If the value x is greater than 90, then threshold1=x, threshold 0=80.

Priority Queues

Each port supports eight egress queues, of which two can be given a priority.

You use the priority level policy class-map command to configure the priority for two classes. One of the classes has to be configured with a priority queue level 1, and the other class has to be configured with a priority queue level 2. Packets on these two queues are subjected to less latency with respect to other queues.


Note
You can configure a priority only with a level.

Only one strict priority or a priority with levels is allowed in one policy map. Multiple priorities with the same priority levels without kbps/percent are allowed in a policy map only if all of them are configured with police.

Related Tasks
Configuring Priority

Queue Buffer

Each 1-gigabit port on the switch is allocated 168 buffers for a wireless port and 300 buffers for a wired port. Each 10-gigabit port is allocated 1800 buffers. At boot time, when there is no policy map enabled on the wired port, there are two queues created by default. Wired ports can have a maximum of 8 queues configured using MQC-based policies. The following table shows which packets go into which one of the queues:

Table 6 DSCP, Precedence, and CoS - Queue Threshold Mapping Table

DSCP, Precedence or CoS

Queue

Threshold

Control Packets

0

2

Rest of Packets

1

2

Note

You can guarantee the availability of buffers, set drop thresholds, and configure the maximum memory allocation for a queue. You use the queue-buffers policy-map class command to configure the queue buffers. You use the queue-limit policy-map class command to configure the maximum thresholds.

There are two types of buffer allocations: hard buffers, which are explicitly reserved for the queue, and soft buffers, which are available for other ports when unused by a given port.

For the wireless port default, Queue 0 will be given 40 percent of the buffers that are available for the interface as hard buffers, that is 67 buffers are allocated for Queue 0 in the context of 1-gigabit ports. The soft maximum for this queue is set to 268 (calculated as 67 * 400/100) for 1-gigabit ports, where 400 is the default maximum threshold that is configured for any queue.

For the wired port default, Queue 0 will be given 40 percent of the buffers that are available for the interface as hard buffers, that is 120 buffers are allocated for Queue 0 in the context of 1-gigabit ports, and 720 buffers in the context of 10-gigabit ports. The soft maximum for this queue is set to 480 (calculated as 120 * 400/100) for 1-gigabit ports and 2880 for 10-gigabit ports, where 400 is the default maximum threshold that is configured for any queue.

Queue 1 does not have any hard buffers allocated. The default soft buffer limit is set to 400 (which is the maximum threshold). The threshold would determine the maximum number of soft buffers that can be borrowed from the common pool.

Queue Buffer Allocation

The buffer allocation to any queue can be tuned using the queue-buffers ratio policy-map class configuration command.

Related Tasks
Configuring Queue Buffers
Related References
Examples: Queue Buffers Configuration

Dynamic Threshold and Scaling

Traditionally, reserved buffers are statically allocated for each queue. No matter whether the queue is active or not, its buffers are held up by the queue. In addition, as the number of queues increases, the portion of the reserved buffers allocated for each queue can become smaller and smaller. Eventually, a situation may occur where there are not enough reserved buffers to support a jumbo frame for all queues.

The switch supports Dynamic Thresholding and Scaling (DTS), which is a feature that provides a fair and efficient allocation of buffer resources. When congestion occurs, this DTS mechanism provides an elastic buffer allocation for the incoming data based on the occupancy of the global/port resources. Conceptually, DTS scales down the queue buffer allocation gradually as the resources are used up to leave room for other queues, and vice versa. This flexible method allows the buffers to be more efficiently and fairly utilized.

As mentioned in the previous sections, there are two limits configured on a queue—a hard limit and a soft limit.

Hard limits are not part of DTS. These buffers are available only for that queue. The sum of the hard limits should be less than the globally set up hard maximum limit. The global hard limit configured for egress queuing is currently set to 5705. In the default scenario when there are no MQC policies configured, the 24 1-gigabit ports would take up 24 * 67 = 1608, and the 4 10-gigabit ports would take up 4 * 720 = 2880, for a total of 4488 buffers, allowing room for more hard buffers to be allocated based upon the configuration.

Soft limit buffers participate in the DTS process. Additionally, some of the soft buffer allocations can exceed the global soft limit allocation. The global soft limit allocation for egress queuing is currently set to 7607. The sum of the hard and soft limits add up to 13312, which in turn translates to 3.4 MB. Because the sum of the soft buffer allocations can exceed the global limit, it allows a specific queue to use a large number of buffers when the system is lightly loaded. The DTS process dynamically adjusts the per-queue allocation as the system becomes more heavily loaded.

Trust Behavior

Trust Behavior for Wired Ports

For wired ports that are connected to the switch (end points such as IP phones, laptops, cameras, telepresence units, or other devices), their DSCP, precedence, or CoS values coming in from these end points are trusted by the switch and therefore are retained in the absence of any explicit policy configuration.

The packets are enqueued to the appropriate queue per the default initial configuration.

In scenarios where the incoming packet type differs from the outgoing packet type, the trust behavior and the queuing behavior are explained in the following table. Note that the default trust mode for a wired port is DSCP based. The trust mode ‘falls back’ to CoS if the incoming packet is a pure Layer 2 packet. You can also change the trust setting from DSCP to CoS. This is accomplished by using an MQC policy that has a class default with a 'set cos cos table default default-cos' action, where default-cos is the name of the table map created (which only performs a default copy).

Table 7 Trust and Queueing Behavior

Incoming Packet

Outgoing Packet

Trust Behavior

Queuing Behavior

Layer 3

Layer 3

Preserve DSCP/Precedence

Based on DSCP

Layer 2

Layer 2

Not applicable

Based on CoS

Tagged

Tagged

Preserve DSCP and CoS

Based on DSCP (trust DSCP takes precedence)

Layer 3

Tagged

Preserve DSCP, CoS is set to 0

Based on DSCP

Port Security on a Trusted Boundary for Cisco IP Phones

In a typical network, you connect a Cisco IP Phone to a switch port and cascade devices that generate data packets from the back of the telephone. The Cisco IP Phone guarantees the voice quality through a shared data link by marking the CoS level of the voice packets as high priority (CoS = 5) and by marking the data packets as low priority (CoS = 0). Traffic sent from the telephone to the switch is typically marked with a tag that uses the 802.1Q header. The header contains the VLAN information and the class of service (CoS) 3-bit field, which is the priority of the packet.

For most Cisco IP Phone configurations, the traffic sent from the telephone to the switch should be trusted to ensure that voice traffic is properly prioritized over other types of traffic in the network. By using the trust device interface configuration command, you configure the switch port to which the telephone is connected to trust the traffic received on that port.


Note

The trust device device_type command available in interface configuration mode is a stand-alone command on the switch. When using this command in an AutoQoS configuration, if the connected peer device is not a corresponding device (defined as a device matching your trust policy), both CoS and DSCP values are set to "0" and any input policy will not take effect. If the connected peer device is a corresponding device, input policy will take effect.

With the trusted setting, you also can use the trusted boundary feature to prevent misuse of a high-priority queue if a user bypasses the telephone and connects the PC directly to the switch. Without trusted boundary, the CoS labels generated by the PC are trusted by the switch (because of the trusted CoS setting). By contrast, trusted boundary uses CDP to detect the presence of a Cisco IP Phone (such as the Cisco IP Phone 7910, 7935, 7940, and 7960) on a switch port. If the telephone is not detected, the trusted boundary feature disables the trusted setting on the switch port and prevents misuse of a high-priority queue. Note that the trusted boundary feature is not effective if the PC and Cisco IP Phone are connected to a hub that is connected to the switch.

Related Tasks
Configuring Trust Behavior for the Device Type

Standard QoS Default Settings

Default Wired QoS Configuration

There are two queues configured by default on each wired interface on the switch. All control traffic traverses and is processed through queue 0. All other traffic traverses and is processed through queue 1.

DSCP Maps

Default CoS-to-DSCP Map

You use the CoS-to-DSCP map to map CoS values in incoming packets to a DSCP value that QoS uses internally to represent the priority of the traffic. The following table shows the default CoS-to-DSCP map. If these values are not appropriate for your network, you need to modify them.

Table 8 Default CoS-to-DSCP Map

CoS Value

DSCP Value

0

0

1

8

2

16

3

24

4

32

5

40

6

48

7

56

Default IP-Precedence-to-DSCP Map

You use the IP-precedence-to-DSCP map to map IP precedence values in incoming packets to a DSCP value that QoS uses internally to represent the priority of the traffic. The following table shows the default IP-precedence-to-DSCP map. If these values are not appropriate for your network, you need to modify them.

Table 9 Default IP-Precedence-to-DSCP Map

IP Precedence Value

DSCP Value

0

0

1

8

2

16

3

24

4

32

5

40

6

48

7

56

Default DSCP-to-CoS Map

You use the DSCP-to-CoS map to generate a CoS value, which is used to select one of the four egress queues. The following table shows the default DSCP-to-CoS map. If these values are not appropriate for your network, you need to modify them.

Table 10 Default DSCP-to-CoS Map

DSCP Value

CoS Value

0–7

0

8–15

1

16–23

2

24–31

3

32–39

4

40–47

5

48–55

6

56–63

7

How to Configure QoS

Configuring Class, Policy, and Table Maps

Creating a Traffic Class

To create a traffic class containing match criteria, use the class-map command to specify the traffic class name, and then use the following match commands in class-map configuration mode, as needed.

Before You Begin

All match commands specified in this configuration task are considered optional, but you must configure at least one match criterion for a class.

SUMMARY STEPS

    1.    configure terminal

    2.    class-map {class-map name | match-any}

    3.    match access-group {index number | name}

    4.    match class-map class-map name

    5.    match cos cos value

    6.    match dscp dscp value

    7.    match ip {dscp dscp value | precedence precedence value }

    8.    match non-client-nrt

    9.    match qos-group qos group value

    10.    match vlan vlan value

    11.    match wlan user-priority wlan value

    12.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1configure terminal


    Example: 
    
Switch# configure terminal
     

    Enters the global configuration mode.

     
    Step 2class-map {class-map name | match-any}


    Example: 
    Switch(config)# class-map test_1000
Switch(config-cmap)#
     

    Enters class map configuration mode.

    • Creates a class map to be used for matching packets to the class whose name you specify.

    • If you specify match-any, one of the match criteria must be met for traffic entering the traffic class to be classified as part of the traffic class. This is the default.

     
    Step 3match access-group {index number | name}


    Example: 
    Switch(config-cmap)# match access-group 100
Switch(config-cmap)#
     

    The following parameters are available for this command:

    • access-group

    • class-map

    • cos

    • dscp

    • ip

    • non-client-nrt

    • precedence

    • qos-group

    • vlan

    • wlan user priority

    (Optional) For this example, enter the access-group ID:

    • Access list index (value from 1 to 2799)

    • Named access list

     

    Step 4match class-map class-map name


    Example: 
    Switch(config-cmap)# match class-map test_2000
Switch(config-cmap)#
     

    (Optional) Matches to another class-map name.

     

    Step 5match cos cos value


    Example: 
    Switch(config-cmap)# match cos 2 3 4 5
Switch(config-cmap)#
     

    (Optional) Matches IEEE 802.1Q or ISL class of service (user) priority values.

    • Enters up to 4 CoS values separated by spaces (0 to 7).

     

    Step 6match dscp dscp value


    Example: 
    Switch(config-cmap)# match dscp af11 af12
Switch(config-cmap)#
     

    (Optional) Matches the DSCP values in IPv4 and IPv6 packets.

     

    Step 7match ip {dscp dscp value | precedence precedence value }


    Example: 
    Switch(config-cmap)# match ip dscp af11 af12
Switch(config-cmap)#
     

    (Optional) Matches IP values including the following:

    • dscp—Matches IP DSCP (DiffServ codepoints).

    • precedence—Matches IP precedence (0 to 7).

     

    Step 8match non-client-nrt


    Example: 
    Switch(config-cmap)# match non-client-nrt
Switch(config-cmap)#
     

    (Optional) Matches non-client NRT (Non-Real-Time).

    Note   

    This match is applicable only for policies on a wireless port. It carries all the multi-destination and AP (non-client) bound traffic.

     

    Step 9match qos-group qos group value


    Example: 
    Switch(config-cmap)# match qos-group 10
Switch(config-cmap)#
     

    (Optional) Matches QoS group value (from 0 to 31).

     

    Step 10match vlan vlan value


    Example: 
    Switch(config-cmap)# match vlan 210
Switch(config-cmap)#
     

    (Optional) Matches a VLAN ID (from 1 to 4095).

     

    Step 11match wlan user-priority wlan value


    Example: 
    Switch(config-cmap)# match wlan user priority 7
Switch(config-cmap)#
     

    (Optional) Matches 802.11e specific values. Enter the user priority 802.11e user priority (0 to 7).

     

    Step 12end


    Example: 
    Switch(config-cmap)# end
     

    Saves the configuration changes.

     

    What to Do Next

    Configure the policy map.

    Related Concepts
    Class Maps
    Related References
    Examples: Classification by Access Control Lists

    Creating a Traffic Policy

    To create a traffic policy, use the policy-map global configuration command to specify the traffic policy name.

    The traffic class is associated with the traffic policy when the class command is used. The class command must be entered after you enter the policy map configuration mode. After entering the class command, the switch is automatically in policy map class configuration mode, which is where the QoS policies for the traffic policy are defined.

    The following policy map class-actions are supported:

    • admit—Admits the request for Call Admission Control (CAC).

    • bandwidth—Bandwidth configuration options.

    • exit—Exits from the QoS class action configuration mode.

    • no—Negates or sets default values for the command.

    • police—Policer configuration options.

    • priority—Strict scheduling priority configuration options for this class.

    • queue-buffers—Queue buffer configuration options.

    • queue-limit—Queue maximum threshold for Weighted Tail Drop (WTD) configuration options.

    • service-policy—Configures the QoS service policy.

    • set—Sets QoS values using the following options:

      • CoS values

      • DSCP values

      • Precedence values

      • QoS group values

      • WLAN values

    • shape—Traffic-shaping configuration options.

    Before You Begin

    You should have first created a class map.

    SUMMARY STEPS

      1.    configure terminal

      2.    policy-map policy-map name

      3.    class {class-name | class-default}

      4.    admit

      5.    bandwidth {kb/s kb/s value | percent percentage | remaining {percent | ratio}}

      6.    exit

      7.    no

      8.    police {target_bit_rate | cir | rate}

      9.    priority {kb/s | level level value | percent percentage value}

      10.    queue-buffers ratio ratio limit

      11.    queue-limit {packets | cos | dscp | percent}

      12.    service-policy policy-map name

      13.    set {cos | dscp | ip | precedence | qos-group | wlan}

      14.    shape average {target _bit_rate | percent}

      15.    end


    DETAILED STEPS
       Command or ActionPurpose
      Step 1configure terminal


      Example: 
      
Switch# configure terminal
       

      Enters the global configuration mode.

       
      Step 2policy-map policy-map name


      Example: 
      Switch(config)# policy-map test_2000
Switch(config-pmap)#
       

      Enters policy map configuration mode.

      Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

       

      Step 3class {class-name | class-default}


      Example: 
      Switch(config-pmap)# class test_1000
Switch(config-pmap-c)#
       

      Specifies the name of the class whose policy you want to create or change.

      You can also create a system default class for unclassified packets.

       

      Step 4admit


      Example: 
      Switch(config-pmap-c)# admit cac wmm-tspec
Switch(config-pmap-c)#
       

      (Optional) Admits the request for Call Admission Control (CAC). For a more detailed example of this command and its usage, see Configuring Call Admission Control.

      Note   

      This command only configures CAC for wireless QoS.

       

      Step 5bandwidth {kb/s kb/s value | percent percentage | remaining {percent | ratio}}


      Example: 
      Switch(config-pmap-c)# bandwidth 50
Switch(config-pmap-c)#
       

      (Optional) Sets the bandwidth using one of the following:

      • kb/s—Kilobits per second, enter a value between 20000 and 10000000 for Kb/s.

      • percent—Enter the percentage of the total bandwidth to be used for this policy map.

      • remaining—Enter the percentage ratio of the remaining bandwidth.

      For a more detailed example of this command and its usage, see Configuring Bandwidth.

       

      Step 6exit


      Example: 
      Switch(config-pmap-c)# exit
Switch(config-pmap-c)#
       

      (Optional) Exits from QoS class action configuration mode.

       

      Step 7no


      Example: 
      Switch(config-pmap-c)# no
Switch(config-pmap-c)#
       

      (Optional) Negates the command.

       

      Step 8police {target_bit_rate | cir | rate}


      Example: 
      Switch(config-pmap-c)# police 100000
Switch(config-pmap-c)#
       

      (Optional) Configures the policer:

      • target_bit_rate—Enter the bit rate per second, enter a value between 8000 and 10000000000.

      • cir—Committed Information Rate

      • rate—Specify police rate, PCR for hierarchical policies or SCR for single-level ATM 4.0 policer policies.

      For a more detailed example of this command and its usage, see Configuring Police.

       

      Step 9priority {kb/s | level level value | percent percentage value}


      Example: 
      Switch(config-pmap-c)# priority percent 50 
Switch(config-pmap-c)#
       

      (Optional) Sets the strict scheduling priority for this class. Command options include:

      • kb/s—Kilobits per second, enter a value between 1 and 2000000.

      • level—Establishes a multi-level priority queue. Enter a value (1 or 2).

      • percent—Enter a percent of the total bandwidth for this priority.

      For a more detailed example of this command and its usage, see Configuring Priority.

       

      Step 10queue-buffers ratio ratio limit


      Example: 
      Switch(config-pmap-c)# queue-buffers ratio 10
Switch(config-pmap-c)#
       

      (Optional) Configures the queue buffer for the class. Enter the queue buffers ratio limit (0 to 100).

      For a more detailed example of this command and its usage, see Configuring Queue Buffers.

       

      Step 11queue-limit {packets | cos | dscp | percent}


      Example: 
      Switch(config-pmap-c)# queue-limit cos 7 percent 50
Switch(config-pmap-c)#
       

      (Optional) Specifies the queue maximum threshold for the tail drop:

      • packets—Packets by default, enter a value between 1 to 2000000.

      • cos—Enter the parameters for each COS value.

      • dscp—Enter the parameters for each DSCP value.

      • percent—Enter the percentage for the threshold.

      For a more detailed example of this command and its usage, see Configuring Queue Limits.

       

      Step 12service-policy policy-map name


      Example: 
      Switch(config-pmap-c)# service-policy test_2000
Switch(config-pmap-c)#
       

      (Optional) Configures the QoS service policy.

       

      Step 13set {cos | dscp | ip | precedence | qos-group | wlan}


      Example: 
      Switch(config-pmap-c)# set cos 7
Switch(config-pmap-c)#
       

      (Optional) Sets the QoS values. Possible QoS configuration values include:

      • cos—Sets the IEEE 802.1Q/ISL class of service/user priority.

      • dscp—Sets DSCP in IP(v4) and IPv6 packets.

      • ip—Sets IP specific values.

      • precedence—Sets precedence in IP(v4) and IPv6 packet.

      • qos-group—Sets the QoS Group.

      • wlan—Sets the WLAN user-priority.

       

      Step 14shape average {target _bit_rate | percent}


      Example: 
      Switch(config-pmap-c) #shape average percent 50
Switch(config-pmap-c) #
       
      (Optional) Sets the traffic shaping. Command parameters include:

      • target_bit_rate—Target bit rate.

      • percent—Percentage of interface bandwidth for Committed Information Rate.

      For a more detailed example of this command and its usage, see Configuring Shaping.

       

      Step 15end


      Example: 
      Switch(config-pmap-c) #end
Switch(config-pmap-c) #
       

      Saves the configuration changes.

       

      What to Do Next

      Configure the interface.

      Related Concepts
      Policy Maps

      Configuring Class-Based Packet Marking

      This procedure explains how to configure the following class-based packet marking features on your switch:

      • CoS value

      • DSCP value

      • IP value

      • Precedence value

      • QoS group value

      • WLAN value

      Before You Begin

      You should have created a class map and a policy map before beginning this procedure.

      SUMMARY STEPS

        1.    configure terminal

        2.    policy-map policy name

        3.    class class name

        4.    set cos {cos value | cos table table-map name | dscp table table-map name | precedence table table-map name | qos-group table table-map name | wlan user-priority table table-map name}

        5.    set dscp {dscp value | default | dscp table table-map name | ef | precedence table table-map name | qos-group table table-map name | wlan user-priority table table-map name}

        6.    set ip {dscp | precedence}

        7.    set precedence {precedence value | cos table table-map name | dscp table table-map name | precedence table table-map name | qos-group table table-map name}

        8.    set qos-group {qos-group value | dscp table table-map name | precedence table table-map name}

        9.    set wlan user-priority {wlan user-priority value | cos table table-map name | dscp table table-map name | qos-group table table-map name | wlan table table-map name}

        10.    end

        11.    show policy-map


      DETAILED STEPS
         Command or ActionPurpose
        Step 1configure terminal


        Example: 
        
Switch# configure terminal
         

        Enters the global configuration mode.

         
        Step 2policy-map policy name


        Example: 
        Switch(config)# policy-map policy1
Switch(config-pmap)#
         

        Enters policy map configuration mode.

        Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

         

        Step 3class class name


        Example: 
        Switch(config-pmap)# class class1
Switch(config-pmap-c)#
         

        Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change.

        Command options for policy class map configuration mode include the following:

        • admit—Admits the request for Call Admission Control (CAC).

        • bandwidth—Bandwidth configuration options.

        • exit—Exits from the QoS class action configuration mode.

        • no—Negates or sets default values for the command.

        • police—Policer configuration options.

        • priority—Strict scheduling priority configuration options for this class.

        • queue-buffers—Queue buffer configuration options.

        • queue-limit—Queue maximum threshold for Weighted Tail Drop (WTD) configuration options.

        • service-policy—Configures the QoS service policy.

        • set—Sets QoS values using the following options:

          • CoS values

          • DSCP values

          • Precedence values

          • QoS group values

          • WLAN values

        • shape—Traffic-shaping configuration options.

        Note   

        This procedure describes the available configurations using set command options. The other command options (admit, bandwidth, etc.) are described in other sections of this guide. Although this task lists all of the possible set commands, only one set command is supported per class.

         

        Step 4set cos {cos value | cos table table-map name | dscp table table-map name | precedence table table-map name | qos-group table table-map name | wlan user-priority table table-map name}


        Example: 
        Switch(config-pmap)# set cos 5
Switch(config-pmap)#
         

        (Optional) Sets the specific IEEE 802.1Q Layer 2 CoS value of an outgoing packet. Values are from 0 to7.

        You can also set the following values using the set cos command:

        • cos table—Sets the CoS value based on a table map.

        • dscp table—Sets the code point value based on a table map.

        • precedence table—Sets the code point value based on a table map.

        • qos-group table—Sets the CoS value from QoS group based on a table map.

        • wlan user-priority table—Sets the CoS value from the WLAN user priority based on a table map.

         

        Step 5set dscp {dscp value | default | dscp table table-map name | ef | precedence table table-map name | qos-group table table-map name | wlan user-priority table table-map name}


        Example: 
        Switch(config-pmap)# set dscp af11
Switch(config-pmap)#
         

        (Optional) Sets the DSCP value.

        In addition to setting specific DSCP values, you can also set the following using the set dscp command:

        • default—Matches packets with default DSCP value (000000).

        • dscp table—Sets the packet DSCP value from DSCP based on a table map.

        • ef—Matches packets with EF DSCP value (101110).

        • precedence table—Sets the packet DSCP value from precedence based on a table map.

        • qos-group table—Sets the packet DSCP value from a QoS group based upon a table map.

        • wlan user-priority table—Sets the packet DSCP value based upon a WLAN user-priority based upon a table map.

         

        Step 6set ip {dscp | precedence}


        Example: 
        Switch(config-pmap)# set ip dscp c3
Switch(config-pmap)#
         

        (Optional) Sets IP specific values. These values are either IP DSCP or IP precedence values.

        You can set the following values using the set ip dscp command:

        • dscp value—Sets a specific DSCP value.

        • default—Matches packets with default DSCP value (000000).

        • dscp table—Sets the packet DSCP value from DSCP based on a table map.

        • ef—Matches packets with EF DSCP value (101110).

        • precedence table—Sets the packet DSCP value from precedence based on a table map.

        • qos-group table—Sets the packet DSCP value from a QoS group based upon a table map.

        • wlan user-priority table—Sets the packet DSCP value based upon a WLAN user-priority based upon a table map.

        You can set the following values using the set ip precedence command:

        • precedence value—Sets the precedence value (from 0 to 7) .

        • cos table—Sets the packet precedence value from Layer 2 CoS based on a table map.

        • dscp table—Sets the packet precedence from DSCP value based on a table map.

        • precedence table—Sets the precedence value from precedence based on a table map

        • qos-group table—Sets the precedence value from a QoS group based upon a table map.

         

        Step 7set precedence {precedence value | cos table table-map name | dscp table table-map name | precedence table table-map name | qos-group table table-map name}


        Example: 
        Switch(config-pmap)# set precedence 5
Switch(config-pmap)#
         

        (Optional) Sets precedence values in IPv4 and IPv6 packets.

        You can set the following values using the set precedence command:

        • precedence value—Sets the precedence value (from 0 to 7) .

        • cos table—Sets the packet precedence value from Layer 2 CoS on a table map.

        • dscp table—Sets the packet precedence from DSCP value on a table map.

        • precedence table—Sets the precedence value from precedence based on a table map.

        • qos-group table—Sets the precedence value from a QoS group based upon a table map.

         

        Step 8set qos-group {qos-group value | dscp table table-map name | precedence table table-map name}


        Example: 
        Switch(config-pmap)# set qos-group 10
Switch(config-pmap)#
         

        (Optional) Sets QoS group values. You can set the following values using this command:

        • qos-group value—A number from 1 to 31.

        • dscp table—Sets the code point value from DSCP based on a table map.

        • precedence table—Sets the code point value from precedence based on a table map.

         

        Step 9set wlan user-priority {wlan user-priority value | cos table table-map name | dscp table table-map name | qos-group table table-map name | wlan table table-map name}


        Example: 
        Switch(config-pmap)# set wlan user-priority 1
Switch(config-pmap)#
         

        (Optional) Sets the WLAN user priority value. You can set the following values using this command:

        • wlan user-priority value—A value between 0 to 7.

        • cos table—Sets the WLAN user priority value from CoS based on a table map.

        • dscp table—Sets the WLAN user priority value from DSCP based on a table map.

        • qos-group table—Sets the WLAN user priority value from QoS group based on a table map.

        • wlan table—Sets the WLAN user priority value from the WLAN user priority based on a table map.

         

        Step 10end


        Example: 
        Switch(config-pmap)# end
Switch#
         

        Saves configuration changes.

         

        Step 11show policy-map


        Example: 
        Switch# show policy-map
         

        (Optional) Displays policy configuration information for all classes configured for all service policies.

         

        What to Do Next

        Attach the traffic policy to an interface using the service-policy command.

        Attaching a Traffic Policy to an Interface

        After the traffic class and traffic policy are created, you must use the service-policy interface configuration command to attach a traffic policy to an interface, and to specify the direction in which the policy should be applied (either on packets coming into the interface or packets leaving the interface).

        Before You Begin

        A traffic class and traffic policy must be created before attaching a traffic policy to an interface.

        SUMMARY STEPS

          1.    configure terminal

          2.    interface type

          3.    service-policy {input policy-map | output policy-map }

          4.    end

          5.    show policy map


        DETAILED STEPS
           Command or ActionPurpose
          Step 1configure terminal


          Example: 
          
Switch# configure terminal
           

          Enters the global configuration mode.

           
          Step 2interface type


          Example: 
          Switch(config)# interface GigabitEthernet1/0/1
Switch(config-if)#
           

          Enters interface configuration mode and configures an interface.

          Command parameters for the interface configuration include:

          • Auto Template— Auto-template interface

          • Capwap—CAPWAP tunnel interface

          • GigabitEthernet—Gigabit Ethernet IEEE 802

          • GroupVI—Group virtual interface

          • Internal Interface— Internal interface

          • Loopback—Loopback interface

          • Null—Null interface

          • Port-channel—Ethernet Channel of interface

          • TenGigabitEthernet—10-Gigabit Ethernet

          • Tunnel—Tunnel interface

          • Vlan—Catalyst VLANs

          • Range—Interface range

           

          Step 3service-policy {input policy-map | output policy-map }


          Example: 
          Switch(config-if)# service-policy output policy_map_01
Switch(config-if)#
           

          Attaches a policy map to an input or output interface. This policy map is then used as the service policy for that interface.

          In this example, the traffic policy evaluates all traffic leaving that interface.

           
          Step 4end


          Example: 
          Switch(config-if)# end
Switch#
           

          Saves configuration changes.

           

          Step 5show policy map


          Example: 
          Switch# show policy map
           

          (Optional) Displays statistics for the policy on the specified interface.

           

          What to Do Next

          Proceed to attach any other traffic policy to an interface, and to specify the direction in which the policy should be applied.

          Related Concepts
          Policy Map on Physical Port

          Classifying, Policing, and Marking Traffic on Physical Ports by Using Policy Maps

          You can configure a nonhierarchical policy map on a physical port that specifies which traffic class to act on. Actions supported are remarking and policing.

          Before You Begin

          You should have already decided upon the classification, policing, and marking of your network traffic by policy maps prior to beginning this procedure.

          SUMMARY STEPS

            1.    configure terminal

            2.    class-map {class-map name | match-any }

            3.    match access-group { access list index | access list name }

            4.    policy-map policy-map-name

            5.    class {class-map-name | class-default}

            6.    set {cos | dscp | ip | precedence | qos-group | wlan user-priority}

            7.    police {target_bit_rate | cir | rate }

            8.    exit

            9.    exit

            10.    interface interface-id

            11.    service-policy input policy-map-name

            12.    end

            13.    show policy-map [policy-map-name [class class-map-name]]

            14.    copy running-config startup-config


          DETAILED STEPS
             Command or ActionPurpose
            Step 1configure terminal


            Example: 
            
Switch# configure terminal
             

            Enters the global configuration mode.

             
            Step 2class-map {class-map name | match-any }


            Example: 
            Switch(config)# class-map ipclass1
Switch(config-cmap)# exit
Switch(config)#
             

            Enters class map configuration mode.

            • Creates a class map to be used for matching packets to the class whose name you specify.

            • If you specify match-any, one of the match criteria must be met for traffic entering the traffic class to be classified as part of the traffic class. This is the default.

             
            Step 3match access-group { access list index | access list name }


            Example: 
            Switch(config-cmap)# match access-group 1000
Switch(config-cmap)# exit
Switch(config)#
             

            Specifies the classification criteria to match to the class map. You can match on the following criteria:

            • access-group—Matches to access group.

            • class-map—Matches to another class map.

            • cos—Matches to a CoS value.

            • dscp—Matches to a DSCP value.

            • ip—Matches to a specific IP value.

            • non-client-nrt—Matches non-client NRT.

            • precedence—Matches precedence in IPv4 and IPv6 packets.

            • qos-group—Matches to a QoS group.

            • vlan—Matches to a VLAN.

            • wlan—Matches to a wireless LAN.

             

            Step 4policy-map policy-map-name


            Example: 
            
Switch(config)# policy-map flowit
Switch(config-pmap)#
             

            Creates a policy map by entering the policy map name, and enters policy-map configuration mode.

            By default, no policy maps are defined.

             
            Step 5class {class-map-name | class-default}


            Example: 
            
Switch(config-pmap)# class ipclass1
Switch(config-pmap-c)#
             

            Defines a traffic classification, and enter policy-map class configuration mode.

            By default, no policy map class-maps are defined.

            If a traffic class has already been defined by using the class-map global configuration command, specify its name for class-map-name in this command.

            A class-default traffic class is predefined and can be added to any policy. It is always placed at the end of a policy map. With an implied match any included in the class-default class, all packets that have not already matched the other traffic classes will match class-default.

             
            Step 6set {cos | dscp | ip | precedence | qos-group | wlan user-priority}


            Example: 
            
Switch(config-pmap-c)# set dscp 45
Switch(config-pmap-c)#
             

            (Optional) Sets the QoS values. Possible QoS configuration values include:

            • cos—Sets the IEEE 802.1Q/ISL class of service/user priority.

            • dscp—Sets DSCP in IP(v4) and IPv6 packets.

            • ip—Sets IP specific values.

            • precedence—Sets precedence in IP(v4) and IPv6 packet.

            • qos-group—Sets QoS group.

            • wlan user-priority—Sets WLAN user priority.

            In this example, the set dscp command classifies the IP traffic by setting a new DSCP value in the packet.

             
            Step 7police {target_bit_rate | cir | rate }


            Example: 
            Switch(config-pmap-c)# police 100000 conform-action transmit exceed-action
drop
Switch(config-pmap-c)#
             

            (Optional) Configures the policer:

            • target_bit_rate—Specifies the bit rate per second, enter a value between 8000 and 10000000000.

            • cir—Committed Information Rate.

            • rate—Specifies the police rate, PCR for hierarchical policies, or SCR for single-level ATM 4.0 policer policies.

            In this example, the police command adds a policer to the class where any traffic beyond the 100000 set target bit rate is dropped.

             

            Step 8exit


            Example: 
            
Switch(config-pmap-c)# exit
             

            Returns to policy map configuration mode.

             
            Step 9exit


            Example: 
            
Switch(config-pmap)# exit
             

            Returns to global configuration mode.

             
            Step 10interface interface-id


            Example: 
            
Switch(config)# interface 
gigabitethernet 2/0/1
             

            Specifies the port to attach to the policy map, and enters interface configuration mode.

            Valid interfaces include physical ports.

             
            Step 11service-policy input policy-map-name


            Example: 
            
Switch(config-if)# service-policy 
input flowit
             

            Specifies the policy-map name, and applies it to an ingress port. Only one policy map per ingress port is supported.

             
            Step 12end


            Example: 
            
Switch(config-if)# end
             

            Returns to privileged EXEC mode.

             
            Step 13show policy-map [policy-map-name [class class-map-name]]


            Example: 
            
Switch# show policy-map
             

            (Optional) Verifies your entries.

             
            Step 14copy running-config startup-config


            Example: 
            
Switch# copy-running-config 
startup-config
             

            (Optional) Saves your entries in the configuration file.

             
            What to Do Next

            If applicable to your QoS configuration, configure classification, policing, and marking of traffic on SVIs by using policy maps.

            Classifying, Policing, and Marking Traffic on SVIs by Using Policy Maps

            Before You Begin

            You should have already decided upon the classification, policing, and marking of your network traffic by using policy maps prior to beginning this procedure.

            SUMMARY STEPS

              1.    configure terminal

              2.    class-map {class-map name | match-any }

              3.    match vlan vlan number

              4.    policy-map policy-map-name

              5.    description description

              6.    class {class-map-name | class-default}

              7.    set {cos | dscp | ip | precedence | qos-group | wlan user-priority}

              8.    police {target_bit_rate | cir | rate}

              9.    exit

              10.    exit

              11.    interface interface-id

              12.    service-policy input policy-map-name

              13.    end

              14.    show policy-map [policy-map-name [class class-map-name]]

              15.    copy running-config startup-config


            DETAILED STEPS
               Command or ActionPurpose
              Step 1configure terminal


              Example: 
              
Switch# configure terminal
               

              Enters the global configuration mode.

               
              Step 2class-map {class-map name | match-any }


              Example: 
              Switch(config)# class-map class_vlan100
               

              Enters class map configuration mode.

              • Creates a class map to be used for matching packets to the class whose name you specify.

              • If you specify match-any, one of the match criteria must be met for traffic entering the traffic class to be classified as part of the traffic class. This is the default.

               
              Step 3match vlan vlan number


              Example: 
              Switch(config-cmap)# match vlan 100
Switch(config-cmap)# exit
Switch(config)#
               

              Specifies the VLAN to match to the class map.

               

              Step 4policy-map policy-map-name


              Example: 
              
Switch(config)# policy-map policy_vlan100
Switch(config-pmap)#
               

              Creates a policy map by entering the policy map name, and enters policy-map configuration mode.

              By default, no policy maps are defined.

               
              Step 5description description


              Example: 
              Switch(config-pmap)# description vlan 100
               

              (Optional) Enters a description of the policy map.

               

              Step 6class {class-map-name | class-default}


              Example: 
              
Switch(config-pmap)# class class_vlan100
Switch(config-pmap-c)#
               

              Defines a traffic classification, and enters the policy-map class configuration mode.

              By default, no policy map class-maps are defined.

              If a traffic class has already been defined by using the class-map global configuration command, specify its name for class-map-name in this command.

              A class-default traffic class is predefined and can be added to any policy. It is always placed at the end of a policy map. With an implied match any included in the class-default class, all packets that have not already matched the other traffic classes will match class-default.

               
              Step 7set {cos | dscp | ip | precedence | qos-group | wlan user-priority}


              Example: 
              
Switch(config-pmap-c)# set dscp af23
Switch(config-pmap-c)#
               

              (Optional) Sets the QoS values. Possible QoS configuration values include:

              • cos—Sets the IEEE 802.1Q/ISL class of service/user priority.

              • dscp—Sets DSCP in IP(v4) and IPv6 packets.

              • ip—Sets IP specific values.

              • precedence—Sets precedence in IP(v4) and IPv6 packet.

              • qos-group—Sets QoS group.

              • wlan user-priority—Sets WLAN user-priority.

              In this example, the set dscp command classifies the IP traffic by matching the packets with a DSCP value of AF23 (010010).

               
              Step 8police {target_bit_rate | cir | rate}


              Example: 
              Switch(config-pmap-c)# police 200000 conform-action transmit 
exceed-action drop
Switch(config-pmap-c)#
               

              (Optional) Configures the policer:

              • target_bit_rate—Specifies the bit rate per second. Enter a value between 8000 and 10000000000.

              • cir—Committed Information Rate.

              • rate—Specifies the police rate, PCR for hierarchical policies, or SCR for single-level ATM 4.0 policer policies.

              In this example, the police command adds a policer to the class where any traffic beyond the 200000 set target bit rate is dropped.

               

              Step 9exit


              Example: 
              
Switch(config-pmap-c)# exit
               

              Returns to policy map configuration mode.

               
              Step 10exit


              Example: 
              
Switch(config-pmap)# exit
               

              Returns to global configuration mode.

               
              Step 11interface interface-id


              Example: 
              
Switch(config)# interface 
gigabitethernet 1/0/3
               

              Specifies the port to attach to the policy map, and enters interface configuration mode.

              Valid interfaces include physical ports.

               
              Step 12service-policy input policy-map-name


              Example: 
              
Switch(config-if)# service-policy 
input policy_vlan100
               

              Specifies the policy-map name, and applies it to an ingress port. Only one policy map per ingress port is supported.

               
              Step 13end


              Example: 
              
Switch(config-if)# end
               

              Returns to privileged EXEC mode.

               
              Step 14show policy-map [policy-map-name [class class-map-name]]


              Example: 
              
Switch# show policy-map
               

              (Optional) Verifies your entries.

               
              Step 15copy running-config startup-config


              Example: 
              
Switch# copy-running-config 
startup-config
               

              (Optional) Saves your entries in the configuration file.

               
              Related Concepts
              Policy Map on VLANs
              Related References
              Examples: Policer VLAN Configuration

              Configuring Table Maps

              Table maps are a form of marking, and also enable the mapping and conversion of one field to another using a table. For example, a table map can be used to map and convert a Layer 2 CoS setting to a precedence value in Layer 3.


              Note

              A table map can be referenced in multiple policies or multiple times in the same policy.

              SUMMARY STEPS

                1.    configure terminal

                2.    table-map name {default {default value | copy | ignore} | exit | map {from from value to to value } | no}

                3.    map from value to value

                4.    exit

                5.    exit

                6.    show table-map

                7.    configure terminal

                8.    policy-map

                9.    class class-default

                10.    set cos dscp table table map name

                11.    end


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1configure terminal


                Example: 
                
Switch# configure terminal
                 

                Enters the global configuration mode.

                 
                Step 2table-map name {default {default value | copy | ignore} | exit | map {from from value to to value } | no}


                Example: 
                Switch(config)# table-map table01
Switch(config-tablemap)#
                 

                Creates a table map and enters the table map configuration mode. In table map configuration mode, you can perform the following tasks:

                • default—Configures the table map default value, or sets the default behavior for a value not found in the table map to copy or ignore.

                • exit—Exits from the table map configuration mode.

                • map—Maps a from to a to value in the table map.

                • no—Negates or sets the default values of the command.

                 

                Step 3map from value to value


                Example: 
                Switch(config-tablemap)# map from 0 to 2
Switch(config-tablemap)# map from 1 to 4
Switch(config-tablemap)# map from 24 to 3
Switch(config-tablemap)# map from 40 to 6 
Switch(config-tablemap)# default 0
Switch(config-tablemap)#
                 

                In this step, packets with DSCP values 0 are marked to the CoS value 2, DSCP value 1 to the CoS value 4, DSCP value 24 to the CoS value 3, DSCP value 40 to the CoS value 6 and all others to the CoS value 0.

                Note   

                The mapping from CoS values to DSCP values in this example is configured by using the set policy map class configuration command as described in a later step in this procedure.

                 

                Step 4exit


                Example: 
                Switch(config-tablemap)# exit
Switch(config)#
                 

                Returns to global configuration mode.

                 

                Step 5exit


                Example: 
                Switch(config) exit
Switch#
                 

                Returns to privileged EXEC mode.

                 

                Step 6show table-map


                Example: 
                Switch# show table-map
Table Map table01
    from 0 to 2
    from 1 to 4
    from 24 to 3
    from 40 to 6
    default 0
                 

                Displays the table map configuration.

                 

                Step 7configure terminal


                Example: 
                Switch# configure terminal
Switch(config)#
                 

                Enters global configuration mode.

                 
                Step 8policy-map


                Example: 
                Switch(config)# policy-map table-policy
Switch(config-pmap)#
                 

                Configures the policy map for the table map.

                 

                Step 9class class-default


                Example: 
                Switch(config-pmap)# class  class-default
Switch(config-pmap-c)#
                 

                Matches the class to the system default.

                 

                Step 10set cos dscp table table map name


                Example: 
                Switch(config-pmap-c)# set cos dscp table table01
Switch(config-pmap-c)#
                 

                If this policy is applied on input port, that port will have trust DSCP enabled on that port and marking will take place depending upon the specified table map.

                 

                Step 11end


                Example: 
                Switch(config-pmap-c)# end
Switch#
                 

                Returns to privileged EXEC mode.

                 

                What to Do Next

                Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                Related Concepts
                Table Map Marking
                Related References
                Examples: Table Map Marking Configuration

                Configuring Trust

                Configuring Trust Behavior for the Device Type

                This procedure explains how to configure trust for one or more device classes within your network configuration.

                Before You Begin

                There are two types of trust behavior supported on the switch:

                • Trust QoS at the policy level—You can configure trust for individual packets by creating specific policy maps and applying them on an interface. If you do not configure a specific policy map, then the default is to trust DSCP.

                • Trust devices at the interface level—You can configure trust for the device using the trust device interface configuration command.


                Note
                The default mode on an interface is trusted and changes to untrusted only when an untrusted device is detected. In the untrusted mode, the DSCP, IP precedence, or CoS value is reset to 0.
                SUMMARY STEPS

                  1.    configure terminal

                  2.    interface type

                  3.    trust device { cisco-phone | cts | ip-camera | media-player }

                  4.    end

                  5.    show interface status


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1configure terminal


                  Example: 
                  
Switch# configure terminal
                   

                  Enters the global configuration mode.

                   
                  Step 2interface type


                  Example:
                  Switch(config)# interface GigabitEthernet1/0/1
Switch(config-if)#
                   

                  Enters interface configuration mode and configures an interface.

                  Command parameters for the interface configuration include:

                  • Auto Template— Auto-Template interface

                  • Capwap—Capwap tunnel interface

                  • GigabitEthernet—Gigabit Ethernet IEEE 802

                  • GroupVI—Group virtual interface

                  • Internal Interface—Internal interface

                  • Loopback—Loopback interface

                  • Null—Null interface

                  • Port-channel—Ethernet Channel of interface

                  • TenGigabitEthernet—10-Gigabit Ethernet

                  • Tunnel—Tunnel interface

                  • Vlan—Catalyst VLANs

                  • range—interface range

                   

                  Step 3trust device { cisco-phone | cts | ip-camera | media-player }


                  Example:
                  Switch(config-if)# trust device cisco-phone
Switch(config-if)#
                   

                  Configures the trust value for the interface. You can configure trust for the following supported devices:

                  • cisco-phone—Cisco IP Phone

                  • cts—Cisco TelePresence system

                  • ip-camera—IPVSC

                  • media-player—DMP

                   

                  Step 4end


                  Example:
                  Switch(config-if)# end
Switch#
                   

                  Saves configuration changes.

                   

                  Step 5show interface status


                  Example:
                  Switch# show interface status
Switch#
                   

                  (Optional) Displays the configured interface's status.

                   

                  What to Do Next

                  Connect the trusted device to the appropriately configured trusted port on the switch.

                  Related Concepts
                  Port Security on a Trusted Boundary for Cisco IP Phones

                  Configuring QoS Features and Functionality

                  Configuring Call Admission Control

                  This task explains how to configure class-based, unconditional packet marking features on your switch for Call Admission Control (CAC).

                  SUMMARY STEPS

                    1.    configure terminal

                    2.    class-map class name

                    3.    match dscp dscp value

                    4.    exit

                    5.    class-map class name

                    6.    match dscp dscp value

                    7.    exit

                    8.    table-map name

                    9.    default copy

                    10.    exit

                    11.    table-map name

                    12.    default copy

                    13.    exit

                    14.    policy-map policy name

                    15.    class class-map-name

                    16.    priority level level_value

                    17.    police [target_bit_rate | cir | rate ]

                    18.    admit cac wmm-tspec

                    19.    rate value

                    20.    wlan-up value

                    21.    exit

                    22.    exit

                    23.    class class name

                    24.    priority level level_value

                    25.    police [target_bit_rate | cir | rate ]

                    26.    admit cac wmm-tspec

                    27.    rate value

                    28.    wlan-up value

                    29.    exit

                    30.    exit

                    31.    policy-map policy name

                    32.    class class-map-name

                    33.    set dscp dscp table table_map_name

                    34.    set wlan user-priority dscp table table_map_name

                    35.    shape average {target bit rate | percent percentage}

                    36.    queue-buffers {ratio ratio value}

                    37.    service-policy policy_map_name

                    38.    end

                    39.    show policy-map


                  DETAILED STEPS
                     Command or ActionPurpose
                    Step 1configure terminal


                    Example: 
                    
Switch# configure terminal
                     

                    Enters the global configuration mode.

                     
                    Step 2class-map class name


                    Example: 
                    Switch(config)# class-map voice
Switch(config-cmap)#
                     

                    Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                    • word—Class map name.

                    • class-default—System default class matching any otherwise unclassified packets.

                     
                    Step 3match dscp dscp value


                    Example: 
                    Switch(config-cmap)#  match dscp 46
                     

                    (Optional) Matches the DSCP values in IPv4 and IPv6 packets.

                     

                    Step 4exit


                    Example: 
                    Switch(config-cmap)# exit
Switch(config)#
                     

                    Returns to global configuration mode.

                     

                    Step 5class-map class name


                    Example: 
                    Switch(config)# class-map video
Switch(config-cmap)#
                     

                    Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                    • word—Class map name.

                    • class-default—System default class matching any otherwise unclassified packets.

                     
                    Step 6match dscp dscp value


                    Example: 
                    Switch(config-cmap)#  match dscp 34
                     

                    (Optional) Matches the DSCP values in IPv4 and IPv6 packets.

                     

                    Step 7exit


                    Example: 
                    Switch(config-cmap)# exit
Switch(config)#
                     

                    Returns to global configuration mode.

                     

                    Step 8table-map name


                    Example: 
                    Switch(config)# table-map  dscp2dscp
Switch(config-tablemap)#
                     

                    Creates a table map and enters the table map configuration mode.

                     

                    Step 9default copy


                    Example: 
                    Switch(config-tablemap)# default copy
                     

                    Sets the default behavior for value not found in the table map to copy.

                    Note   

                    This is the default option. You can also do a mapping of values for DSCP to DSCP.

                     

                    Step 10exit


                    Example: 
                    Switch(config-tablemap)# exit
Switch(config)#
                     

                    Returns to global configuration mode.

                     

                    Step 11table-map name


                    Example: 
                    Switch(config)# table-map dscp2up
Switch(config-tablemap)#
                     

                    Creates a new table map and enters the table map configuration mode.

                     

                    Step 12default copy


                    Example: 
                    Switch(config-tablemap)# default copy
                     

                    Sets the default behavior for value not found in the table map to copy.

                    Note   

                    This is the default option. You can also do a mapping of values for DSCP to UP.

                     

                    Step 13exit


                    Example: 
                    Switch(config-tablemap)# exit
Switch(config)#
                     

                    Returns to global configuration mode.

                     

                    Step 14policy-map policy name


                    Example: 
                    Switch(config)#  policy-map ssid_child_cac
Switch(config-pmap)#
                     

                    Enters policy map configuration mode.

                    Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                     

                    Step 15class class-map-name


                    Example: 
                    
Switch(config-pmap)# class voice
                     

                    Defines an interface-level traffic classification, and enters policy-map configuration mode.

                     
                    Step 16priority level level_value


                    Example: 
                    Switch(config-pmap-c)# priority level 1
                     

                    The priority command assigns a strict scheduling priority for the class.

                    Note   

                    Priority level 1 is more important than priority level 2. Priority level 1 reserves bandwidth that is processed first for QoS, so its latency is very low. Both priority level 1 and 2 reserve bandwidth.

                     

                    Step 17police [target_bit_rate | cir | rate ]


                    Example: 
                    Switch(config-pmap-c)#  police cir 10m
                     

                    (Optional) Configures the policer:

                    • target_bit_rate—Specifies the bit rate per second. Enter a value between 8000 and 10000000000.

                    • cir—Committed Information Rate.

                    • rate—Specifies the police rate, PCR for hierarchical policies, or SCR for single-level ATM 4.0 policer policies.

                     
                    Step 18admit cac wmm-tspec


                    Example: 
                    Switch(config-pmap-c)# admit cac wmm-tspec
Switch(config-pmap-cac-wmm)#
                     

                    Configures call admission control for the policy map.

                    Note   

                    This command only configures CAC for wireless QoS.

                     

                    Step 19rate value


                    Example: 
                    Switch(config-pmap-admit-cac-wmm)# rate 5000
                     

                    Configures the target bit rate (Kilo Bits per second). Enter a value from 8 to 10000000.

                     

                    Step 20wlan-up value


                    Example: 
                    Switch(config-pmap-admit-cac-wmm)# wlan-up 6 7
                     

                    Configures the WLAN UP value. Enter a value from 0 to 7.

                     

                    Step 21exit


                    Example: 
                    Switch(config-pmap-admit-cac-wmm)# exit
Switch(config-pmap-c)#
                     

                    Returns to policy map class configuration mode.

                     

                    Step 22exit


                    Example: 
                    Switch(config-pmap-c)# exit
Switch(config-pmap)#
                     

                    Returns to policy map configuration mode.

                     

                    Step 23class class name


                    Example: 
                    Switch(config-pmap)# class video
Switch(config-pmap-c)#
                     

                    Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                    • word—Class map name.

                    • class-default—System default class matching any otherwise unclassified packets.

                     
                    Step 24priority level level_value


                    Example: 
                    Switch(config-pmap-c)# priority level 2
                     

                    The priority command assigns a strict scheduling priority for the class.

                    Note   

                    Priority level 1 is more important than priority level 2. Priority level 1 reserves bandwidth that is processed first for QoS, so its latency is very low. Both priority level 1 and 2 reserve bandwidth.

                     

                    Step 25police [target_bit_rate | cir | rate ]


                    Example: 
                    Switch(config-pmap-c)#  police cir 20m
                     

                    (Optional) Configures the policer:

                    • target_bit_rate—Specifies the bit rate per second. Enter a value between 8000 and 10000000000.

                    • cir—Committed Information Rate.

                    • rate—Specifies the police rate, PCR for hierarchical policies, or SCR for single-level ATM 4.0 policer policies.

                     
                    Step 26admit cac wmm-tspec


                    Example: 
                    Switch(config-pmap-c)# admit cac wmm-tspec
Switch(config-pmap-admit-cac-wmm)#
                     

                    Configures call admission control for the policy map.

                    Note   

                    This command only configures CAC for wireless QoS.

                     

                    Step 27rate value


                    Example: 
                    Switch(config-pmap-admit-cac-wmm)# rate 5000
                     

                    Configures the target bit rate (Kilo Bits per second). Enter a value from 8 to 10000000.

                     

                    Step 28wlan-up value


                    Example: 
                    Switch(config-pmap-admit-cac-wmm)# wlan-up 4 5
                     

                    Configures the WLAN UP value. Enter a value from 0 to 7.

                     

                    Step 29exit


                    Example: 
                    Switch(config-pmap-cac-wmm)# exit
Switch(config-pmap)#
                     

                    Returns to policy map configuration mode.

                     

                    Step 30exit


                    Example: 
                    Switch(config-pmap)# exit
Switch(config)#
                     

                    Returns to global configuration mode.

                     

                    Step 31policy-map policy name


                    Example: 
                    Switch(config)# policy-map ssid_cac
Switch(config-pmap)#
                     

                    Enters policy map configuration mode.

                    Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                     

                    Step 32class class-map-name


                    Example: 
                    Switch(config-pmap)# class default
                     

                    Defines an interface-level traffic classification, and enters policy-map configuration mode.

                    In this example, the class map is set to default.

                     
                    Step 33set dscp dscp table table_map_name


                    Example: 
                    
Switch(config-pmap-c)#  set dscp dscp table dscp2dscp
                     

                    (Optional) Sets the QoS values. In this example, the set dscp dscp table command creates a table map and sets its values.

                     
                    Step 34set wlan user-priority dscp table table_map_name


                    Example: 
                    Switch(config-pmap-c)#   set wlan user-priority dscp table dscp2up
                     

                    (Optional) Sets the QoS values. In this example, the set wlan user-priority dscp table command sets the WLAN user priority.

                     
                    Step 35shape average {target bit rate | percent percentage}


                    Example: 
                    Switch(config-pmap-c)# shape average 100000000
                     

                    Configures the average shape rate. You can configure the average shape rate by target bit rates (bits per second) or by percentage of interface bandwidth for the Committed Information Rate (CIR).

                     

                    Step 36queue-buffers {ratio ratio value}


                    Example: 
                    Switch(config-pmap-c)# queue-buffers ratio 0
                     

                    Configures the relative buffer size for the queue.

                    Note    The sum of all configured buffers in a policy must be less than or equal to 100 percent. Unallocated buffers are evenly distributed to all the remaining queues.

                     

                    Step 37service-policy policy_map_name


                    Example: 
                    Switch(config-pmap-c)#  service-policy ssid_child_cac
                     

                    Specifies the policy map for the service policy.

                     

                    Step 38end


                    Example: 
                    Switch(config-pmap)# end
Switch#
                     

                    Saves configuration changes.

                     

                    Step 39show policy-map


                    Example: 
                    Switch# show policy-map
                     

                    (Optional) Displays policy configuration information for all classes configured for all service policies.

                     

                    What to Do Next

                    Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                    For additional information about CAC, refer to the System Management Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches).

                    Configuring Bandwidth

                    This procedure explains how to configure bandwidth on your switch.

                    Before You Begin

                    You should have created a class map for bandwidth before beginning this procedure.

                    SUMMARY STEPS

                      1.    configure terminal

                      2.    policy-map policy name

                      3.    class class name

                      4.    bandwidth {Kb/s | percent percentage | remaining { ratio ratio }}

                      5.    end

                      6.    show policy-map


                    DETAILED STEPS
                       Command or ActionPurpose
                      Step 1configure terminal


                      Example: 
                      
Switch# configure terminal
                       

                      Enters the global configuration mode.

                       
                      Step 2policy-map policy name


                      Example: 
                      Switch(config)# policy-map policy_bandwidth01
Switch(config-pmap)#
                       

                      Enters policy map configuration mode.

                      Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                       

                      Step 3class class name


                      Example: 
                      Switch(config-pmap)# class class_bandwidth01
Switch(config-pmap-c)#
                       

                      Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                      • word—Class map name.

                      • class-default—System default class matching any otherwise unclassified packets.

                       

                      Step 4bandwidth {Kb/s | percent percentage | remaining { ratio ratio }}


                      Example: 
                      Switch(config-pmap-c)# bandwidth 200000
Switch(config-pmap-c)#
                       

                      Configures the bandwidth for the policy map. The parameters include:

                      • Kb/s—Configures a specific value in kilobits per second (from 20000 to 10000000).

                      • percent-—Allocates minimum bandwidth to a particular class based on a percentage. The queue can oversubscribe bandwidth in case other queues do not utilize the entire port bandwidth. The total sum cannot exceed 100 percent, and in case it is less than 100 percent, the rest of the bandwidth is equally divided along all bandwidth queues.

                      • remaining— Allocates minimum bandwidth to a particular class. The queue can oversubscribe bandwidth in case other queues do not utilize entire port bandwidth. The total sum cannot exceed 100 percent. It is preferred to use this command when the priority command is used for certain queues in the policy. You can also assign ratios rather than percentages to each queue; the queues will be assigned certain weights which are inline with these ratios. Ratios can range from 0 to 100. Total bandwidth ratio allocation for the policy in this case can exceed 100.
                      Note   

                      You cannot mix bandwidth types on a policy map. For example, you cannot configure bandwidth in a single policy map using both a bandwidth percent and in kilobits per second.

                       

                      Step 5end


                      Example: 
                      Switch(config-pmap-c)# end
Switch#
                       

                      Saves configuration changes.

                       

                      Step 6show policy-map


                      Example: 
                      Switch# show policy-map
                       

                      (Optional) Displays policy configuration information for all classes configured for all service policies.

                       

                      What to Do Next

                      Configure any additional policy maps for QoS for your network. After creating the policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                      Related Concepts
                      Bandwidth

                      Configuring Police

                      This procedure explains how to configure policing on your switch.

                      Before You Begin

                      You should have created a class map for policing before beginning this procedure.

                      SUMMARY STEPS

                        1.    configure terminal

                        2.    policy-map policy name

                        3.    class class name

                        4.    police {target_bit_rate [burst bytes | bc | conform-action | pir ] | cir {target_bit_rate | percent percentage} | rate {target_bit_rate | percent percentage} conform-action transmit exceed-action {drop [violate action] | set-cos-transmit | set-dscp-transmit | set-prec-transmit | transmit [violate action] }}

                        5.    end

                        6.    show policy-map


                      DETAILED STEPS
                         Command or ActionPurpose
                        Step 1configure terminal


                        Example: 
                        
Switch# configure terminal
                         

                        Enters the global configuration mode.

                         
                        Step 2policy-map policy name


                        Example: 
                        Switch(config)# policy-map policy_police01
Switch(config-pmap)#
                         

                        Enters policy map configuration mode.

                        Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                         

                        Step 3class class name


                        Example: 
                        Switch(config-pmap)# class class_police01
Switch(config-pmap-c)#
                         

                        Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                        • word—Class map name.

                        • class-default—System default class matching any otherwise unclassified packets.

                         

                        Step 4police {target_bit_rate [burst bytes | bc | conform-action | pir ] | cir {target_bit_rate | percent percentage} | rate {target_bit_rate | percent percentage} conform-action transmit exceed-action {drop [violate action] | set-cos-transmit | set-dscp-transmit | set-prec-transmit | transmit [violate action] }}


                        Example: 
                        Switch(config-pmap-c)# police 8000 conform-action transmit exceed-action drop
Switch(config-pmap-c)#
                         

                        The following police subcommand options are available:

                        • target_bit_rate—Bits per second (from 8000 to 10000000000).

                          • burst bytes—Enter a value from 1000 to 512000000.

                          • bc—Conform burst.

                          • conform-action—Action taken when rate is less than conform burst.

                          • pir—Peak Information Rate.

                        • cir—Committed Information Rate.

                          • target_bit_rate—Target bit rate (8000 to10000000000).

                          • percent—Percentage of interface bandwidth for CIR.

                        • rate—Specifies the police rate, PCR for hierarchical policies, or SCR for single-level ATM 4.0 policer policies.

                          • target_bit_rate—Target Bit Rate (8000 to 10000000000).

                          • percent—Percentage of interface bandwidth for rate.

                        The following police conform-action transmit exceed-action subcommand options are available:

                        • drop—Drops the packet.

                        • set-cos-transmit—Sets the CoS value and sends it.

                        • set-dscp-transmit—Sets the DSCP value and sends it.

                        • set-prec-transmit—Rewrites the packet precedence and sends it.

                        • transmit—Transmits the packet.

                        Note   

                        Policer-based markdown actions are only supported using table maps. Only one markdown table map is allowed for each marking field in the switch.

                         

                        Step 5end


                        Example: 
                        Switch(config-pmap-c)# end
Switch#
                         

                        Saves configuration changes.

                         

                        Step 6show policy-map


                        Example: 
                        Switch# show policy-map
                         

                        (Optional) Displays policy configuration information for all classes configured for all service policies.

                         

                        What to Do Next

                        Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                        Related Concepts
                        Single-Rate Two-Color Policing
                        Dual-Rate Three-Color Policing
                        Policing
                        Token-Bucket Algorithm
                        Related References
                        Examples: Single-Rate Two-Color Policing Configuration
                        Examples: Dual-Rate Three-Color Policing Configuration
                        Examples: Policing Action Configuration
                        Examples: Policing Units

                        Configuring Priority

                        This procedure explains how to configure priority on your switch.

                        The switch supports giving priority to specified queues. There are two priority levels available (1 and 2).

                        Note

                        Queues supporting voice and video should be assigned a priority level of 1.

                        Before You Begin

                        You should have created a class map for priority before beginning this procedure.

                        SUMMARY STEPS

                          1.    configure terminal

                          2.    policy-map policy name

                          3.    class class name

                          4.    priority [Kb/s [burst_in_bytes] | level level_value [Kb/s [burst_in_bytes] | percent percentage [burst_in_bytes] ] | percent percentage [burst_in_bytes] ]

                          5.    end

                          6.    show policy-map


                        DETAILED STEPS
                           Command or ActionPurpose
                          Step 1configure terminal


                          Example: 
                          
Switch# configure terminal
                           

                          Enters the global configuration mode.

                           
                          Step 2policy-map policy name


                          Example: 
                          Switch(config)# policy-map policy_priority01
Switch(config-pmap)#
                           

                          Enters policy map configuration mode.

                          Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                           

                          Step 3class class name


                          Example: 
                          Switch(config-pmap)# class class_priority01
Switch(config-pmap-c)#
                           

                          Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                          • word—Class map name.

                          • class-default—System default class matching any otherwise unclassified packets.

                           
                          Step 4priority [Kb/s [burst_in_bytes] | level level_value [Kb/s [burst_in_bytes] | percent percentage [burst_in_bytes] ] | percent percentage [burst_in_bytes] ]


                          Example: 
                          Switch(config-pmap-c)# priority level 1
Switch(config-pmap-c)#
                           

                          (Optional) The priority command assigns a strict scheduling priority for the class.

                          The command options include:

                          • Kb/s—Specifies the kilobits per second (from 1 to 2000000).

                            • burst_in_bytes—Specifies the burst in bytes (from 32 to 2000000).

                          • level level_value—Specifies the multilevel (1-2) priority queue.

                            • Kb/s—Specifies the kilobits per second (from 1 to 2000000).

                              • burst_in_bytes—Specifies the burst in bytes (from 32 to 2000000).

                            • percent—Percentage of the total bandwidth.

                              • burst_in_bytes—Specifies the burst in bytes (from 32 to 2000000).

                          • percent—Percentage of the total bandwidth.

                            • burst_in_bytes—Specifies the burst in bytes (32 to 2000000).

                          Note   

                          Priority level 1 is more important than priority level 2. Priority level 1 reserves bandwidth that is processed first for QoS, so its latency is very low. Both priority level 1 and 2 reserve bandwidth.

                           

                          Step 5end


                          Example: 
                          Switch(config-pmap-c)# end
Switch#
                           

                          Saves configuration changes.

                           

                          Step 6show policy-map


                          Example: 
                          Switch# show policy-map
                           

                          (Optional) Displays policy configuration information for all classes configured for all service policies.

                           

                          What to Do Next

                          Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                          Related Concepts
                          Priority Queues

                          Configuring Queues and Shaping

                          Configuring Egress Queue Characteristics

                          Depending on the complexity of your network and your QoS solution, you may need to perform all of the procedures in this section. You need to make decisions about these characteristics:

                          • Which packets are mapped by DSCP, CoS, or QoS group value to each queue and threshold ID?

                          • What drop percentage thresholds apply to the queues, and how much reserved and maximum memory is needed for the traffic type?

                          • How much of the fixed buffer space is allocated to the queues?

                          • Does the bandwidth of the port need to be rate limited?

                          • How often should the egress queues be serviced and which technique (shaped, shared, or both) should be used?


                          Note
                          You can only configure the egress queues on the switch.

                          Configuring Queue Buffers

                          The switch allows you to allocate buffers to queues. If there is no allocation made to buffers, then they are divided equally for all queues. You can use the queue-buffer ratio to divide it in a particular ratio. Since by default DTS (Dynamic Threshold and Scaling) is active on all queues, these are soft buffers.


                          Note

                          The queue-buffer ratio is supported on both wired and wireless ports, but the queue-buffer ratio cannot be configured with a queue-limit.

                          Before You Begin

                          The following are prerequisites for this procedure:

                          • You should have created a class map for the queue buffer before beginning this procedure.

                          • You must have configured either bandwidth, shape, or priority on the policy map prior to configuring the queue buffers.

                          SUMMARY STEPS

                            1.    configure terminal

                            2.    policy-map policy name

                            3.    class class name

                            4.    bandwidth {Kb/s | percent percentage | remaining { ratio ratio value }}

                            5.    queue-buffers {ratio ratio value}

                            6.    end

                            7.    show policy-map


                          DETAILED STEPS
                             Command or ActionPurpose
                            Step 1configure terminal


                            Example: 
                            
Switch# configure terminal
                             

                            Enters the global configuration mode.

                             
                            Step 2policy-map policy name


                            Example: 
                            Switch(config)# policy-map policy_queuebuffer01
Switch(config-pmap)#
                             

                            Enters policy map configuration mode.

                            Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                             

                            Step 3class class name


                            Example: 
                            Switch(config-pmap)# class class_queuebuffer01
Switch(config-pmap-c)#
                             

                            Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                            • word—Class map name.

                            • class-default—System default class matching any otherwise unclassified packets.

                             

                            Step 4bandwidth {Kb/s | percent percentage | remaining { ratio ratio value }}


                            Example: 
                            Switch(config-pmap-c)# bandwidth percent 80
Switch(config-pmap-c)#
                             

                            Configures the bandwidth for the policy map. The command parameters include:

                            • Kb/s—Use this command to configure a specific value. The range is 20000 to 10000000.

                            • percent—Allocates a minimum bandwidth to a particular class using a percentage. The queue can oversubscribe bandwidth in case other queues do not utilize the entire port bandwidth. The total sum cannot exceed 100 percent, and in case it is less than 100 percent, the rest of the bandwidth is equally divided along all bandwidth queues.

                            • remaining—Allocates a minimum bandwidth to a particular class. The queue can oversubscribe bandwidth in case other queues do not utilize entire port bandwidth. The total sum cannot exceed 100 percent. It is preferred to use this command when the priority command is used for certain queues in the policy. You can also assign ratios rather than a percentage to each queue; the queues will be assigned certain weights that are inline with these ratios. Ratios can range from 0 to 100. Total bandwidth ratio allocation for the policy in this case can exceed 100.
                            Note   

                            You cannot mix bandwidth types on a policy map.

                             

                            Step 5queue-buffers {ratio ratio value}


                            Example: 
                            Switch(config-pmap-c)# queue-buffers ratio 10
Switch(config-pmap-c)#
                             

                            Configures the relative buffer size for the queue.

                            Note    The sum of all configured buffers in a policy must be less than or equal to 100 percent. Unallocated buffers are are evenly distributed to all the remaining queues.

                             

                            Step 6end


                            Example: 
                            Switch(config-pmap-c)# end
Switch#
                             

                            Saves configuration changes.

                             

                            Step 7show policy-map


                            Example: 
                            Switch# show policy-map
                             

                            (Optional) Displays policy configuration information for all classes configured for all service policies.

                             

                            What to Do Next

                            Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                            Related Concepts
                            Queue Buffer Allocation
                            Related References
                            Examples: Queue Buffers Configuration

                            Configuring Queue Limits

                            You use queue limits to configure Weighted Tail Drop (WTD). WTD ensures the configuration of more than one threshold per queue. Each class of service is dropped at a different threshold value to provide for QoS differentiation. With the switch, each queue has 3 explicit programmable threshold classes—0, 1, 2. Therefore, the enqueue/drop decision of each packet per queue is determined by the packet’s threshold class assignment, which is determined by the DSCP, CoS, or QoS group field of the frame header.

                            WTD also uses a soft limit, and therefore you are allowed to configure the queue limit to up to 400 percent (maximum four times the reserved buffer from common pool). This soft limit prevents overrunning the common pool without impacting other features.


                            Note
                            You can only configure queue limits on the switch egress queues on wired ports.
                            Before You Begin

                            The following are prerequisites for this procedure:

                            • You should have created a class map for the queue limits before beginning this procedure.

                            • You must have configured either bandwidth, shape, or priority on the policy map prior to configuring the queue limits.

                            SUMMARY STEPS

                              1.    configure terminal

                              2.    policy-map policy name

                              3.    class class name

                              4.    bandwidth {Kb/s | percent percentage | remaining { ratio ratio value }}

                              5.    queue-limit {packets packets | cos {cos value { maximum threshold value | percent percentage } | values {cos value | percent percentage } } | dscp {dscp value {maximum threshold value | percent percentage} | match packet {maximum threshold value | percent percentage} | default {maximum threshold value | percent percentage} | ef {maximum threshold value | percent percentage} | dscp values dscp value} | percent percentage }}

                              6.    end

                              7.    show policy-map


                            DETAILED STEPS
                               Command or ActionPurpose
                              Step 1configure terminal


                              Example: 
                              
Switch# configure terminal
                               

                              Enters the global configuration mode.

                               
                              Step 2policy-map policy name


                              Example: 
                              Switch(config)# policy-map policy_queuelimit01
Switch(config-pmap)#
                               

                              Enters policy map configuration mode.

                              Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                               

                              Step 3class class name


                              Example: 
                              Switch(config-pmap)# class class_queuelimit01
Switch(config-pmap-c)#
                               

                              Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                              • word—Class map name.

                              • class-default—System default class matching any otherwise unclassified packets.

                               
                              Step 4bandwidth {Kb/s | percent percentage | remaining { ratio ratio value }}


                              Example: 
                              Switch(config-pmap-c)# bandwidth 500000
Switch(config-pmap-c)#
                               

                              Configures the bandwidth for the policy map. The parameters include:

                              • Kb/s—Use this command to configure a specific value. The range is 20000 to 10000000.

                              • percent—Allocates a minimum bandwidth to a particular class. The queue can oversubscribe bandwidth in case other queues do not utilize the entire port bandwidth. The total sum cannot exceed 100 percent, and in case it is less than 100 percent, the rest of the bandwidth is equally divided along all bandwidth queues.

                              • remaining—Allocates a minimum bandwidth to a particular class. The queue can oversubscribe bandwidth in case other queues do not utilize entire port bandwidth. The total sum cannot exceed 100 percent. It is preferred to use this command when the priority command is used for certain queues in the policy. You can also assign ratios rather than a percentage to each queue; the queues will be assigned certain weights that are inline with these ratios. Ratios can range from 0 to 100. Total bandwidth ratio allocation for the policy in this case can exceed 100.
                              Note   

                              You cannot mix bandwidth types on a policy map.

                               

                              Step 5queue-limit {packets packets | cos {cos value { maximum threshold value | percent percentage } | values {cos value | percent percentage } } | dscp {dscp value {maximum threshold value | percent percentage} | match packet {maximum threshold value | percent percentage} | default {maximum threshold value | percent percentage} | ef {maximum threshold value | percent percentage} | dscp values dscp value} | percent percentage }}


                              Example: 
                              Switch(config-pmap-c)# queue-limit dscp 3 percent 20
Switch(config-pmap-c)# queue-limit dscp 4 percent 30
Switch(config-pmap-c)# queue-limit dscp 5 percent 40
                               

                              Sets the queue limit threshold percentage values.

                              With every queue, there are three thresholds (0,1,2), and there are default values for each of these thresholds. Use this command to change the default or any other queue limit threshold setting. For example, if DSCP 3, 4, and 5 packets are being sent into a specific queue in a configuration, then you can use this command to set the threshold percentages for these three DSCP values. For additional information about queue limit threshold values, see Weighted Tail Drop.

                              Note   

                              The switch does not support absolute queue-limit percentages. The switch only supports DSCP or CoS queue-limit percentages.

                               

                              Step 6end


                              Example: 
                              Switch(config-pmap-c)# end
Switch#
                               

                              Saves configuration changes.

                               

                              Step 7show policy-map


                              Example: 
                              Switch# show policy-map
                               

                              (Optional) Displays policy configuration information for all classes configured for all service policies.

                               

                              What to Do Next

                              Proceed to configure any additional policy maps for QoS for your network. After creating your policy maps, proceed to attach the traffic policy or polices to an interface using the service-policy command.

                              Related Concepts
                              Weighted Tail Drop
                              Related References
                              Examples: Queue-limit Configuration

                              Configuring Shaping

                              You use the shape command to configure shaping (maximum bandwidth) for a particular class. The queue's bandwidth is restricted to this value even though the port has additional bandwidth left. You can configure shaping as an average percent, as well as a shape average value in bits per second.

                              Before You Begin

                              You should have created a class map for shaping before beginning this procedure.

                              SUMMARY STEPS

                                1.    configure terminal

                                2.    policy-map policy name

                                3.    class class name

                                4.    shape average {target bit rate | percent percentage}

                                5.    end

                                6.    show policy-map


                              DETAILED STEPS
                                 Command or ActionPurpose
                                Step 1configure terminal


                                Example: 
                                
Switch# configure terminal
                                 

                                Enters the global configuration mode.

                                 
                                Step 2policy-map policy name


                                Example: 
                                Switch(config)# policy-map policy_shaping01
Switch(config-pmap)#
                                 

                                Enters policy map configuration mode.

                                Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

                                 

                                Step 3class class name


                                Example: 
                                Switch(config-pmap)# class class_shaping01
Switch(config-pmap-c)#
                                 

                                Enters policy class map configuration mode. Specifies the name of the class whose policy you want to create or change. Command options for policy class map configuration mode include the following:

                                • word—Class map name.

                                • class-default—System default class matching any otherwise unclassified packets.

                                 
                                Step 4shape average {target bit rate | percent percentage}


                                Example: 
                                Switch(config-pmap-c)# shape average percent 50
Switch(config-pmap-c)#
                                 

                                Configures the average shape rate. You can configure the average shape rate by target bit rates (bits per second) or by percentage of interface bandwidth for the Committed Information Rate (CIR).

                                Note    For the egress class-default SSID policy, you must configure the queue buffer ratio as 0 after you configure the average shape rate.

                                 

                                Step 5end


                                Example: 
                                Switch(config-pmap-c)# end
Switch#
                                 

                                Saves configuration changes.

                                 

                                Step 6show policy-map


                                Example: 
                                Switch# show policy-map
                                 

                                (Optional) Displays policy configuration information for all classes configured for all service policies.

                                 

                                What to Do Next

                                Configure any additional policy maps for QoS for your network. After creating your policy maps, attach the traffic policy or polices to an interface using the service-policy command.

                                Related Concepts
                                Average Rate Shaping
                                Hierarchical Shaping
                                Related References
                                Examples: Average Rate Shaping Configuration

                                Monitoring QoS

                                The following commands can be used to monitor QoS on the switch.

                                Table 11 Monitoring QoS

                                Command

                                Description

                                show class-map [class_map_name]

                                Displays a list of all class maps configured.

                                show class-map type control subscriber {all | name }

                                Displays control class map and statistics.

                                • all—Displays information for all class maps.

                                • name—Displays configured class maps.

                                show policy-map [policy_map_name]

                                Displays a list of all policy maps configured. Command parameters include:

                                • policy map name

                                • interface

                                • session

                                show policy-map interface { Auto-template | Capwap | GigabitEthernet | GroupVI | InternalInterface | Loopback | Lspvif | | Null | Port-channel | TenGigabitEthernet | Tunnel | Vlan | brief | class | input | output | wireless }

                                Displays the runtime representation and statistics of all the policies configured on the switch. Command parameters include:

                                • Auto-template—Auto-Template interface

                                • Capwap—CAPWAP tunnel interface

                                • GigabitEthernet—Gigabit Ethernet IEEE.802.3z

                                • GroupVI—Group virtual interface

                                • InternalInterface—Internal interface

                                • Loopback—Loopback interface

                                • Lspvif—LSP virtual interface

                                • Null—Null interface

                                • Port-channel—Ethernet channel of interfaces

                                • TenGigabitEthernet—10-Gigabit Ethernet

                                • Tunnel—Tunnel interface

                                • Vlan—Catalyst VLANs

                                • brief—Brief description of policy maps

                                • class—Statistics for individual class

                                • input—Input policy

                                • output—Output policy

                                • Wireless—wireless

                                show policy-map interface wireless ap [access point]

                                Displays the runtime representation and statistics for all the wireless APs on the switch.

                                show policy-map interface wireless ssid [ssid]

                                Displays the runtime representation and statistics for all the SSID targets on the switch.

                                show policy-map interface wireless client mac [mac_address]

                                Displays the runtime representation and statistics for all the client targets on the switch.

                                show policy-map session [ input | output | uid UUID ]

                                Displays the session QoS policy. Command parameters include:

                                • input—Input policy

                                • output—Output policy

                                • uid—Policy based on SSS unique identification.

                                show table-map

                                Displays all the table maps and their configurations.

                                show platform qos wireless {afd { client | ssid } | stats { bssid bssid-value | client name | ssid {ssid-value | all} client all}}

                                Displays wireless targets. The following command parameters are supported:

                                • afd—AFD information

                                • stats—Statistics information

                                show policy-map interface wireless ssid name ssid-name [radio type {24ghz | 5ghz} ap name ap-name | ap name ap-name]

                                Displays SSID policy configuration on an access point.

                                Configuration Examples for QoS

                                Examples: Classification by Access Control Lists

                                This example shows how to classify packets for QoS by using access control lists (ACLs):

                                Switch# configure terminal
Switch(config)# access-list 101 permit ip host 12.4.1.1 host 15.2.1.1 
Switch(config)# class-map acl-101
Switch(config-cmap)# description match on access-list 101
Switch(config-cmap)# match access-group 101
Switch(config-cmap)#

                                After creating a class map by using an ACL, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Related Concepts
                                Class Maps
                                Related Tasks
                                Creating a Traffic Class

                                Examples: Class of Service Layer 2 Classification

                                This example shows how to classify packets for QoS using a class of service Layer 2 classification:

                                Switch# configure terminal
Switch(config)# class-map cos
Switch(config-cmap)# match cos ?
  <0-7>  Enter up to 4 class-of-service values separated by white-spaces
Switch(config-cmap)# match cos 3 4 5
Switch(config-cmap)#

                                After creating a class map by using a CoS Layer 2 classification, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Examples: Class of Service DSCP Classification

                                This example shows how to classify packets for QoS using a class of service DSCP classification:

                                Switch# configure terminal
Switch(config)# class-map dscp
Switch(config-cmap)# match dscp af21 af22 af23 
Switch(config-cmap)#

                                After creating a class map by using a DSCP classification, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Examples: VLAN ID Layer 2 Classification

                                This example shows how to classify for QoS using a VLAN ID Layer 2 classification:

                                Switch# configure terminal
Switch(config)# class-map vlan-120
Switch(config-cmap)# match vlan ?
  <1-4095>  VLAN id
Switch(config-cmap)# match vlan 120
Switch(config-cmap)#

                                After creating a class map by using a VLAN Layer 2 classification, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Examples: Classification by DSCP or Precedence Values

                                This example shows how to classify packets by using DSCP or precedence values:

                                Switch# configure terminal
Switch(config)# class-map prec2
Switch(config-cmap)# description matching precedence 2 packets
Switch(config-cmap)# match ip precedence 2 
Switch(config-cmap)# exit
Switch(config)# class-map ef 
Switch(config-cmap)# description EF traffic
Switch(config-cmap)# match ip dscp ef
Switch(config-cmap)#

                                After creating a class map by using a DSCP or precedence values, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Examples: Hierarchical Classification

                                The following is an example of a hierarchical classification, where a class named parent is created, which matches another class named child. The class named child matches based on the IP precedence being set to 2.

                                Switch# configure terminal
Switch(config)# class-map child
Switch(config-cmap)# match ip precedence 2
Switch(config-cmap)# exit
Switch(config)# class-map parent
Switch(config-cmap)# match class child
Switch(config-cmap)#

                                After creating the parent class map, you then create a policy map for the class, and apply the policy map to an interface for QoS.

                                Related Concepts
                                Hierarchical QoS

                                Examples: Hierarchical Policy Configuration

                                The following is an example of a configuration using hierarchical polices: 

                                Switch# configure terminal
Switch(config)# class-map c1
Switch(config-cmap)# match dscp 30
Switch(config-cmap)# exit

Switch(config)# class-map c2
Switch(config-cmap)# match precedence 4
Switch(config-cmap)# exit

Switch(config)# class-map c3
Switch(config-cmap)# exit

Switch(config)# policy-map child
Switch(config-pmap)# class c1
Switch(config-pmap-c)# priority level 1
Switch(config-pmap-c)# police rate percent 20 conform-action transmit exceed action drop 
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)# exit

Switch(config-pmap)# class c2
Switch(config-pmap-c)# bandwidth 20000
Switch(config-pmap-c)# exit
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# bandwidth 20000
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit

Switch(config)# policy-map parent
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# shape average 1000000
Switch(config-pmap-c)# service-policy child
Switch(config-pmap-c)# end
                                The following example shows a hierarchical policy using table maps: 
                                Switch(config)# table-map dscp2dscp
 Switch(config-tablemap)# default copy
Switch(config)# table-map dscp2up
Switch(config-tablemap)# map from 46 to 6
Switch(config-tablemap)# map from 34 to 5
Switch(config-tablemap)# default copy
Switch(config)# policy-map ssid_child_policy
Switch(config-pmap)# class voice
Switch(config-pmap-c)# priority level 1
Switch(config-pmap-c)# police 15000000
Switch(config-pmap)# class video
Switch(config-pmap-c)# priority level 2
Switch(config-pmap-c)# police 10000000
Switch(config)# policy-map ssid_policy
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# shape average 30000000
Switch(config-pmap-c)# queue-buffer ratio 0
Switch(config-pmap-c)# set dscp dscp table dscp2dscp
Switch(config-pmap-c)# service-policy ssid_child_policy

                                Examples: Classification for Voice and Video

                                This example describes how to classify packet streams for voice and video using switch specific information.

                                In this example, voice and video are coming in from end-point A into GigabitEthernet1/0/1 on the switch and have precedence values of 5 and 6, respectively. Additionally, voice and video are also coming from end-point B into GigabitEthernet1/0/2 on the switch with DSCP values of EF and AF11, respectively.

                                Assume that all the packets from the both the interfaces are sent on the uplink interface, and there is a requirement to police voice to 100 Mbps and video to 150 Mbps.

                                To classify per the above requirements, a class to match voice packets coming in on GigabitEthernet1/0/1 is created, named voice-interface-1, which matches precedence 5. Similarly another class for voice is created, named voice-interface-2, which will match voice packets in GigabitEthernet1/0/2. These classes are associated to two separate policies named input-interface-1, which is attached to GigabitEthernet1/0/1, and input-interface-2, which is attached to GigabitEthernet1/0/2. The action for this class is to mark the qos-group to 10. To match packets with QoS-group 10 on the output interface, a class named voice is created which matches on QoS-group 10. This is then associated to another policy named output-interface, which is associated to the uplink interface. Video is handled in the same way, but matches on QoS-group 20.

                                The following example shows how classify using the above switch specific information:

                                Switch(config)#
Switch(config)# class-map voice-interface-1
Switch(config-cmap)# match ip precedence 5
Switch(config-cmap)# exit

Switch(config)# class-map video-interface-1
Switch(config-cmap)# match ip precedence 6
Switch(config-cmap)# exit

Switch(config)# class-map voice-interface-2
Switch(config-cmap)# match ip dscp ef
Switch(config-cmap)# exit

Switch(config)# class-map video-interface-2
Switch(config-cmap)# match ip dscp af11
Switch(config-cmap)# exit

Switch(config)# policy-map input-interface-1
Switch(config-pmap)# class voice-interface-1
Switch(config-pmap-c)# set qos-group 10
Switch(config-pmap-c)# exit

Switch(config-pmap)# class video-interface-1
Switch(config-pmap-c)# set qos-group 20

Switch(config-pmap-c)# policy-map input-interface-2
Switch(config-pmap)# class voice-interface-2
Switch(config-pmap-c)# set qos-group 10
Switch(config-pmap-c)# class video-interface-2
Switch(config-pmap-c)# set qos-group 20
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit

Switch(config)# class-map voice
Switch(config-cmap)# match qos-group 10
Switch(config-cmap)# exit

Switch(config)# class-map video
Switch(config-cmap)# match qos-group 20

Switch(config)# policy-map output-interface
Switch(config-pmap)# class voice
Switch(config-pmap-c)# police 256000 conform-action transmit exceed-action drop
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)# exit
  
Switch(config-pmap)# class video
Switch(config-pmap-c)# police 1024000 conform-action transmit exceed-action drop
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)# exit

                                Examples: Average Rate Shaping Configuration

                                The following example shows how to configure average rate shaping:

                                Switch# configure terminal
Switch(config)# class-map prec1
Switch(config-cmap)# description matching precedence 1 packets
Switch(config-cmap)# match ip precedence 1
Switch(config-cmap)# end

Switch# configure terminal
Switch(config)# class-map prec2
Switch(config-cmap)# description matching precedence 2 packets
Switch(config-cmap)# match ip precedence 2
Switch(config-cmap)# exit

Switch(config)# policy-map shaper
Switch(config-pmap)# class prec1
Switch(config-pmap-c)# shape average 512000
Switch(config-pmap-c)# exit

Switch(config-pmap)# policy-map shaper
Switch(config-pmap)# class prec2
Switch(config-pmap-c)# shape average 512000
Switch(config-pmap-c)# exit

Switch(config-pmap)# class class-default
Switch(config-pmap-c)# shape average 1024000

                                After configuring the class maps, policy map, and shape averages for your configuration, proceed to then apply the policy map to the interface for QoS.

                                Related Concepts
                                Average Rate Shaping
                                Related Tasks
                                Configuring Shaping

                                Examples: Queue-limit Configuration

                                The following example shows how to configure a queue-limit policy based upon DSCP values and percentages:

                                Switch# configure terminal
Switch#(config)# policy-map port-queue
Switch#(config-pmap)# class dscp-1-2-3
Switch#(config-pmap-c)# bandwidth percent 20
Switch#(config-pmap-c)# queue-limit dscp 1 percent 80
Switch#(config-pmap-c)# queue-limit dscp 2 percent 90
Switch#(config-pmap-c)# queue-limit dscp 3 percent 100
Switch#(config-pmap-c)# exit

Switch#(config-pmap)# class dscp-4-5-6
Switch#(config-pmap-c)# bandwidth percent 20
Switch#(config-pmap-c)# queue-limit dscp 4 percent 20
Switch#(config-pmap-c)# queue-limit dscp 5 percent 30
Switch#(config-pmap-c)# queue-limit dscp 6 percent 20
Switch#(config-pmap-c)# exit

Switch#(config-pmap)# class dscp-7-8-9
Switch#(config-pmap-c)# bandwidth percent 20
Switch#(config-pmap-c)# queue-limit dscp 7 percent 20
Switch#(config-pmap-c)# queue-limit dscp 8 percent 30
Switch#(config-pmap-c)# queue-limit dscp 9 percent 20
Switch#(config-pmap-c)# exit

Switch#(config-pmap)# class dscp-10-11-12
Switch#(config-pmap-c)# bandwidth percent 20
Switch#(config-pmap-c)# queue-limit dscp 10 percent 20
Switch#(config-pmap-c)# queue-limit dscp 11 percent 30
Switch#(config-pmap-c)# queue-limit dscp 12 percent 20
Switch#(config-pmap-c)# exit

Switch#(config-pmap)# class dscp-13-14-15
Switch#(config-pmap-c)# bandwidth percent 10
Switch#(config-pmap-c)# queue-limit dscp 13 percent 20
Switch#(config-pmap-c)# queue-limit dscp 14 percent 30
Switch#(config-pmap-c)# queue-limit dscp 15 percent 20
Switch#(config-pmap-c)# end  
Switch#

                                After finishing with the above policy map queue-limit configuration, you can then proceed to apply the policy map to an interface for QoS.

                                Related Concepts
                                Weighted Tail Drop
                                Related Tasks
                                Configuring Queue Limits

                                Examples: Queue Buffers Configuration

                                The following example shows how configure a queue buffer policy and then apply it to an interface for QoS:

                                Switch# configure terminal
Switch(config)# policy-map policy1001  
Switch(config-pmap)# class class1001
Switch(config-pmap-c)# bandwidth remaining ratio 10
Switch(config-pmap-c)# queue-buffer ratio ?
  <0-100>  Queue-buffers ratio limit
Switch(config-pmap-c)# queue-buffer ratio 20
Switch(config-pmap-c)# end

Switch# configure terminal
Switch(config)# interface gigabitEthernet2/0/3
Switch(config-if)# service-policy output policy1001
Switch(config-if)# end
                                Related Concepts
                                Queue Buffer Allocation
                                Related Tasks
                                Configuring Queue Buffers

                                Examples: Policing Action Configuration

                                The following example displays the various policing actions that can be associated to the policer. These actions are accomplished using the conforming, exceeding, or violating packet configurations. You have the flexibility to drop, mark and transmit, or transmit packets that have exceeded or violated a traffic profile.

                                For example, a common deployment scenario is one where the enterprise customer polices traffic exiting the network towards the service provider and marks the conforming, exceeding and violating packets with different DSCP values. The service provider could then choose to drop the packets marked with the exceeded and violated DSCP values under cases of congestion, but may choose to transmit them when bandwidth is available.


                                Note

                                The Layer 2 fields can be marked to include the CoS fields, and the Layer 3 fields can be marked to include the precedence and the DSCP fields.

                                One useful feature is the ability to associate multiple actions with an event. For example, you could set the precedence bit and the CoS for all conforming packets. A submode for an action configuration could then be provided by the policing feature.

                                This is an example of a policing action configuration:

                                Switch# configure terminal
Switch(config)# policy-map police
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# police cir 1000000 pir 2000000 
Switch(config-pmap-c-police)# conform-action transmit
Switch(config-pmap-c-police)# exceed-action set-dscp-transmit dscp table exceed-markdown-table
Switch(config-pmap-c-police)# violate-action set-dscp-transmit dscp table violate-markdown-table  
Switch(config-pmap-c-police)# end

                                In this example, the exceed-markdown-table and violate-mark-down-table are table maps.


                                Note

                                Policer-based markdown actions are only supported using table maps. Only one markdown table map is allowed for each marking field in the switch.

                                Related Concepts
                                Policing
                                Related Tasks
                                Configuring Police

                                Examples: Policer VLAN Configuration

                                The following example displays a VLAN policer configuration. At the end of this configuration, the VLAN policy map is applied to an interface for QoS.

                                Switch# configure terminal
Switch(config)# class-map vlan100
Switch(config-cmap)# match vlan 100
Switch(config-cmap)# exit
Switch(config)# policy-map vlan100
Switch(config-pmap)# policy-map class vlan100
Switch(config-pmap-c)# police 100000 bc conform-action transmit exceed-action drop
Switch(config-pmap-c-police)# end
Switch# configure terminal
Switch(config)# interface gigabitEthernet1/0/5
Switch(config-if)#  service-policy input vlan100
                                Related Concepts
                                Policy Map on VLANs
                                Related Tasks
                                Classifying, Policing, and Marking Traffic on SVIs by Using Policy Maps

                                Examples: Policing Units

                                The following examples display the various units of policing that are supported for QoS. The policing unit is the basis on which the token bucket works .

                                The following units of policing are supported:

                                • CIR and PIR are specified in bits per second. The burst parameters are specified in bytes. This is the default mode; it is the unit that is assumed when no units are specified. The CIR and PIR can also be configured in percent, in which case the burst parameters have to be configured in milliseconds.

                                • CIR and PIR are specified in packets per second. In this case, the burst parameters are configured in packets as well.

                                The following is an example of a policer configuration in bits per second:

                                Switch(config)# policy-map bps-policer
Switch(config-pmap)# class class-default
Switch(config-pmap-c) # police rate 256000 bps burst 1000 bytes 
conform-action transmit exceed-action drop

                                The following is an example of a policer configuration in packets per second. In this configuration, a dual-rate three-color policer is configured where the units of measurement is packet. The burst and peak burst are all specified in packets.

                                Switch(config)# policy-map pps-policer
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# police rate 5000 pps burst 100 packets 
peak-rate 10000 pps peak-burst 200 packets conform-action transmit 
exceed-action drop violate-action drop
                                Related Concepts
                                Token-Bucket Algorithm
                                Related Tasks
                                Configuring Police

                                Examples: Single-Rate Two-Color Policing Configuration

                                The following example shows how to configure a single-rate two-color policer:

                                Switch(config)# class-map match-any prec1
Switch(config-cmap)# match ip precedence 1
Switch(config-cmap)# exit
Switch(config)# policy-map policer
Switch(config-pmap)# class prec1
Switch(config-pmap-c)# police cir 256000 conform-action transmit exceed-action drop 
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)#
                                Related Concepts
                                Single-Rate Two-Color Policing
                                Related Tasks
                                Configuring Police

                                Examples: Dual-Rate Three-Color Policing Configuration

                                The following example shows how to configure a dual-rate three-color policer:

                                Switch# configure terminal
Switch(config)# policy-Map dual-rate-3color-policer
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# police cir 64000 bc 2000 pir 128000 be 2000
Switch(config-pmap-c-police)# conform-action transmit
Switch(config-pmap-c-police)# exceed-action set-dscp-transmit dscp table exceed-markdown-table
Switch(config-pmap-c-police)# violate-action set-dscp-transmit dscp table violate-markdown-table
Switch(config-pmap-c-police)# exit
Switch(config-pmap-c)#

                                In this example, the exceed-markdown-table and violate-mark-down-table are table maps.


                                Note

                                Policer based markdown actions are only supported using table maps. Only one markdown table map is allowed for each marking field in the switch.

                                Related Concepts
                                Dual-Rate Three-Color Policing
                                Related Tasks
                                Configuring Police

                                Examples: Table Map Marking Configuration

                                The following steps and examples show how to use table map marking for your QoS configuration:

                                1. Define the table map.

                                  Define the table-map using the table-map command and indicate the mapping of the values. This table does not know of the policies or classes within which it will be used. The default command in the table map indicates the value to be copied into the ‘to’ field when there is no matching ‘from’ field. In the example, a table map named table-map1 is created. The mapping defined is to convert the value from 0 to 1 and from 2 to 3, while setting the default value to 4. 

                                  Switch(config)# table-map table-map1
Switch(config-tablemap)# map from 0 to 1
Switch(config-tablemap)# map from 2 to 3
Switch(config-tablemap)# default 4
Switch(config-tablemap)# exit

                                2. Define the policy map where the table map will be used.

                                  In the example, the incoming CoS is mapped to the DSCP based on the mapping specified in the table table-map1. For this example, if the incoming packet has a DSCP of 0, the CoS in the packet is set 1. If no table map name is specified the command assumes a default behavior where the value is copied as is from the ‘from’ field (DSCP in this case) to the ‘to’ field (CoS in this case). Note however, that while the CoS is a 3-bit field, the DSCP is a 6-bit field, which implies that the CoS is copied to the first three bits in the DSCP. 

                                  Switch(config)# policy map policy1
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# set cos dscp table table-map1
Switch(config-pmap-c)# exit

                                3. Associate the policy to an interface.

                                  Switch(config)# interface GigabitEthernet1/0/1
Switch(config-if)# service-policy output policy1
Switch(config-if)# exit
                                Related Concepts
                                Table Map Marking
                                Related Tasks
                                Configuring Table Maps

                                Example: Table Map Configuration to Retain CoS Markings

                                The following example shows how to use table maps to retain CoS markings on an interface for your QoS configuration.

                                The cos-trust-policy policy (configured in the example) is enabled in the ingress direction to retain the CoS marking coming into the interface. If the policy is not enabled, only the DSCP is trusted by default. If a pure Layer 2 packet arrives at the interface, then the CoS value will be rewritten to 0 when there is no such policy in the ingress port for CoS.

                                Switch# configure terminal
Switch(config)# table-map cos2cos
Switch(config-tablemap)# default copy
Switch(config-tablemap)# exit


Switch(config)# policy map cos-trust-policy
Switch(config-pmap)# class class-default
Switch(config-pmap-c)# set cos cos table cos2cos
Switch(config-pmap-c)# exit

Switch(config)# interface GigabitEthernet1/0/2
Switch(config-if)# service-policy input cos-trust-policy
Switch(config-if)# exit

                                Where to Go Next

                                Review the auto-QoS documentation to see if you can use these automated capabilities for your QoS configuration.

                                Additional References for QoS

                                Related Documents

                                Related Topic Document Title

                                For complete syntax and usage information for the commands used in this chapter.

                                QoS Command Reference (Catalyst 3850 Switches)

                                Cisco IOS Quality of Service Solutions Command Reference

                                Call Admission Control (CAC)

                                		System Management Configuration Guide (Catalyst 3850 Switches)

                                System Management Command Reference (Catalyst 3850 Switches)

                                Multicast Shaping and Policing Rate

                                		IP Multicast Routing Configuration Guide (Catalyst 3850 Switches)

                                Application Visibility and Control

                                		System Management Configuration Guide (Catalyst 3850 Switches)

                                System Management Command Reference (Catalyst 3850 Switches)

                                Application Visibility and Control

                                		System Management Configuration Guide (Catalyst 3850 Switches)

                                System Management Command Reference (Catalyst 3850 Switches)

                                Error Message Decoder

                                Description Link

                                To help you research and resolve system error messages in this release, use the Error Message Decoder tool.

                                https:/​/​www.cisco.com/​cgi-bin/​Support/​Errordecoder/​index.cgi

                                Standards and RFCs

                                Standard/RFC Title

                                —

                                MIBs

                                MIB MIBs Link

                                All supported MIBs for this release.

                                To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

                                http:/​/​www.cisco.com/​go/​mibs

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                                To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

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                                Feature History and Information for QoS

                                Release

                                Modification

                                Cisco IOS XE 3.3SE

                                This feature was introduced.

                                Cisco IOS XE 3.3SE

                                Consistent system default trust behavior for both wired and wireless ports.

                                The Cisco IOS XE 3.2 Release supported different trust defaults for wired and wireless ports. The trust default for wired ports was the same as for this software release. For wireless ports, the default system behavior was non-trust, which meant that when the switch came up, all markings for the wireless ports were defaulted to zero and no traffic received priority treatment. For compatibility with an existing wired switch, all traffic went to the best-effort queue by default. The access point performed priority queuing by default.

                                The default trust behavior in the case of wireless ports could be changed by using the no qos wireless default untrust command.

                                Cisco IOS XE 3.3SE

                                Support for 3 radios and 11ac.

                                Cisco IOS XE 3.3SE

                                New classification counters available in the show policy-map command.

                                Note   

                                This feature is only available on wired targets.

                                Cisco IOS XE 3.6E

                                Marking and policing actions for ingress SSID policies. Client policies are applied at the access point.

                                Cisco IOS XE 3.6E

                                New classification counters for wireless targets available in the show policy-map command.

                                Cisco IOS XE 3.6E

                                Statistics are supported only for ingress policies.