H Commands

This chapter describes the Cisco NX-OS quality of service (QoS) commands that begin with H.

hardware multicast disable-slow-port-pruning

To disable slow port pruning on multicast packets, use the hardware multicast disable-slow-port-pruning command. To enable show port pruning, use the no form of this command.

hardware multicast disable-slow-port-pruning

no hardware multicast disable-slow-port-pruning

 
Syntax Description

This command has no arguments or keywords.

 
Command Default

Enabled

 
Command Modes

Global configuration mode

 
Command History

Release
Modification

5.2(1)N1(1)

This command was introduced.

 
Usage Guidelines


Note This command is applicable to only Cisco Nexus 5548 switches.


Examples

This example shows how to disable slow port pruning for multicast packets on a switch:

switch(config)# hardware multicast disable-slow-port-pruning
switch(config)#
 

 
Related Commands

Command
Description

hardware unicast voq-limit

Enables the VOQ limit.

show running-config

Displays the running configuration on a switch.

hardware profile tcam feature interface-qos limit

To configure the QoS TCAM limit, use the hardware profile tcam feature interface-qos limit command.

hardware profile tcam feature interface-qos limit tcam-size

 
Syntax Description

tcam-size

Interface QoS TCAM limit. The TCAM size can be from 7- 446 entries.

 
Command Default

None

 
Command Modes

Global configuration mode

 
Command History

Release
Modification

5.2(1)N1(1)

This command was introduced.

 
Usage Guidelines

No interface policy entry should be present after the interface_qos limit in the QoS region of any TCAM.

Examples

This example shows how to set the interface QoS TCAM limit to 20 entries:

switch(config)# configue terminal
switch(config)# hardware profile tcam feature interface-qos limit 20
switch(config)# show hardware profile tcam feature qos
Feature Limit
--------------------------------------------------------------------------------
Interface 20
vlan-qos + global-qos 428
 
switch(config)# copy running-config startup-config
 

 
Related Commands

Command
Description

show hardware profile tcam feature qos

Displays the limits of the QoS TCAMs.

hardware qos-policy-offload

To enable QoS policy offloading on a Fabric Extender (FEX), use the hardware qos-policy-offload command in fabric extender configuration mode. To disable QoS policy offloading, use the no form of this command.

hardware card-type qos-policy-offload

no hardware card-type qos-policy-offload

 
Syntax Description

card-type

Fabric Extender card type. The following Fabric Extender card types are supported:

  • N2224TP —Fabric Extender 24x1G 2x10G SFP+ Module
  • N2232P —Fabric Extender 32x10G SFP+ 8x10G SFP+ Module
  • N2232TM —Fabric Extender 32x10GBase-T 8x10G SFP+ Module
  • N2248T —Fabric Extender 48x1G 4x10G SFP+ Module
  • N2248TP-E —Fabric Extender 48x1G 4x10G SFP+ Module
  • N2248PQ —Fabric Extender 48x10G SPF+ 16x10G SFP+ Module
  • N2232TM-E —Fabric Extender 32x10GBase-T 8x10G SFP+ Module
  • NB22IBM —Fabric Extender 14x10G SFP+ 8x10G SFP+ Module

 
Command Default

Disabled

 
Command Modes

Fabric extender configuration mode (config-fex)#

 
Command History

Release
Modification

7.0(3)N1(1)

This command was introduced.

 
Usage Guidelines

If the existing system-level QoS policy is accepted by the FEX, the QoS policy is enforced by the FEX.

If the existing system-level QoS policy is not accepted by the FEX, an error message is displayed and the fabric ports associated with the FEX are error-disabled, which prevents the FEX from being online.

When you disable the feature, the existing system-level QoS policy is removed from the FEX and the enforcement of the existing QoS policy is changed from ACL-based to Class-of-Service (CoS) based. The TCAM entries are removed and packet classification on the FEX is done using the cos2q map in the FEX hardware.

The maximum number of access control entries (ACEs) in a policy applied on the FEX is 30 when offloaded. In Cisco NX-OS Release 7.3(x), the FEX offload capability using interface QoS policies is up to 100 ACEs and up to only 30 ACEs using system QoS policies.

Examples

This example shows how to enable QoS policy offloading on a Cisco Nexus 2248T Fabric Extender:

switch(config)# fex 110
switch(config-fex)# hardware N2248T qos-policy-offload
switch(config-fex)#
 

This example shows how to disable QoS policy offloading on a Cisco Nexus 2248T Fabric Extender:

switch(config)# fex 110
switch(config-fex)# no hardware N2248T qos-policy-offload
switch(config-fex)#
 

 
Related Commands

Command
Description

fex

Creates a Fabric Extender and enters fabric extender configuration mode.

show fex

Displays all configured Fabric Extender chassis connected to the switch.

show running-config

Displays the contents of the currently running configuration file, including information on FEX-based ACL classification settings.

hardware unicast voq-limit

To enable the virtual output queuing (VOQ) limit for unicast traffic on a switch, use the hardware unicast voq-limit command. To disable the VOQ limit, use the no form of this command.

hardware unicast voq-limit

no hardware unicast voq-limit

 
Syntax Description

This command has no arguments or keywords.

 
Command Default

Disabled

 
Command Modes

Global configuration mode

 
Command History

Release
Modification

5.2(1)N1(1)

This command was introduced.

 
Usage Guidelines


Note This command is applicable to only Cisco Nexus 5548 switches.


To alleviate congestion and blocking, you can use virtual output queuing (VOQ) to prevent one blocked receiver from affecting traffic that is being sent to other noncongested receivers (head-of-line blocking).

Examples

This example shows how to enable the VOQ limits for unicast packets on a switch:

switch(config)# hardware unicast voq-limit
switch(config)#
 

 
Related Commands

Command
Description

hardware multicast disable-slow-port-pruning

Disables slow port pruning on the switch.

show running-config

Displays the running configuration on a switch.