The Catalyst 3560CX series switches supporting 10G SFP+ uplink ports and MGig ports can be part of horizontal stacking. We can use SFP+ with the optical cables and copper cables on the MGig ports to connect boxes placed at different location to form a stack, where the compact boxes are placed in different floors or buildings. We can form half-ring or full-ring based on need, and remaining uplink ports will continue to work as network ports.

When we convert a network port to stack port, it will continue to work as network port without any impact to current running configuration until next reload of switch. All current configurations of that particular network port will be lost after reload of switch once port comes up as Stack port.

When we convert a stack port back to network port it will continue to work as stack port until next reload of switch. After reload port comes up as network port with default configuration.

Note

When uplink ports are working as stack ports, those particular uplink interfaces (ex: Te1/0/1) will not be listed in any show command or will not be available under any config command, unlike any other network port. They will be made available only after reload of the switch once ports are converted back to network.

A switch stack has up to eight stack members connected through their stack ports. A switch stack always has one active switch.

A standalone device is a device stack with one stack member that also operates as the active switch. You can connect one standalone device to another to create a stack containing two stack members, with one of them as the active switch. You can connect standalone devices to an existing device stack to increase the stack membership.

The stack member number (1 to 8) identifies each member in the switch stack. The member number also determines the interface-level configuration that a stack member uses. You can display the stack member number by using the show switch EXEC command.

A new, out-of-the-box device (one that has not joined a device stack or has not been manually assigned a stack member number) ships with a default stack member number of 1. When it joins a device stack, its default stack member number changes to the lowest available member number in the stack.

Stack members in the same stack cannot have the same stack member number. Every stack member, including a standalone device, retains its member number until you manually change the number or unless the number is already being used by another member in the stack.

• If you manually change the stack member number by using the switch current-stack-member-number renumber new-stack-member-number command, the new number goes into effect after that stack member resets (or after you use the reload slot stack-member-number privileged EXEC command) and only if that number is not already assigned to any other members in the stack. Another way to change the stack member number is by changing the device_NUMBER environment variable.

  If the number is being used by another member in the stack, the device selects the lowest available number in the stack.

  If you manually change the number of a stack member and no interface-level configuration is associated with that new member number, that stack member resets to its default configuration.

  You cannot use the switch current-stack-member-number renumber new-stack-member-number command on a provisioned device. If you do, the command is rejected.

• If you move a stack member to a different device stack, the stack member retains its number only if the number is not being used by another member in the stack. If it is being used, the device selects the lowest available number in the stack.

• If you merge device stacks, the device that join the device stack of a new active device select the lowest available numbers in the stack.

As described in the hardware installation guide, you can use the device port LEDs in Stack mode to visually determine the stack member number of each stack member.

In the default mode Stack LED will blink in green color only on the active switch. However, when we scroll the Mode button to Stack option - Stack LED will glow green on all the stack members.

When mode button is scrolled to Stack option, the switch number of each stack member will be displayed as LEDs on the first five ports of that switch. The switch number is displayed in binary format for all stack members. On the switch, the amber LED indicates value 0 and green LED indicates value 1.

Example for switch number 5 (Binary - 00101):

First five LEDs glow as follows on stack member with switch number 5.

• Port-1 : Amber

• Port-2 : Amber

• Port-3 : Green

• Port-4 : Amber

• Port-5 : Green

Similarly, the first five LEDs glow amber or green, depending on the switch number on all stack members.

Note

If you connect a Horizontal stack port to a normal network port on other end, stack port transmission/reception will be disabled within 30 seconds if no SDP packets are received from the other end. Stack port will not go down but only transmission/reception will be disabled. The log message shown below will be displayed on the console. Once the peer end network port is converted to stack port, transmission/reception on this stack port will be enabled. %STACKMGR-4-HSTACK_LINK_CONFIG: Verify peer stack port setting for hstack StackPort-1 switch 5 (hostname-switchnumber)

A higher priority value for a stack member increases the probability of it being elected active switch and retaining its stack member number. The priority value can be 1 to 15. The default priority value is 1. You can display the stack member priority value by using the show switch EXEC command.

Note	We recommend assigning the highest priority value to the device that you prefer to be the active device. This ensures that the device is reelected as the active device if a reelection occurs.

To change the priority value for a stack member, use the switch stack-member-number priority new priority-value command. For more information, see the “Setting the Stack Member Priority Value” section.

The new priority value takes effect immediately but does not affect the current active device. The new priority value helps determine which stack member is elected as the new active device when the current active device or the device stack resets.

The configuration files record these settings:

• System-level (global) configuration settings such as IP, STP, VLAN, and SNMP settings that apply to all stack members

• Stack member interface-specific configuration settings that are specific for each stack member

Note	The interface-specific settings of the active switch are saved if the active switch is replaced without saving the running configuration to the startup configuration.

A new, out-of-box device joining a switch stack uses the system-level settings of that switch stack. If a device is moved to a different switch stack before it is powered on, that device loses its saved configuration file and uses the system-level configuration of the new switch stack. If the device is powered on as a standalone device before it joins the new switch stack, the stack will reload. When the stack reloads, the new device may become the device, retain its configuration and overwrite the configuration files of the other stack members.

The interface-specific configuration of each stack member is associated with the stack member number. Stack members retain their numbers unless they are manually changed or they are already used by another member in the same switch stack. If the stack member number changes, the new number goes into effect after that stack member resets.

• If an interface-specific configuration does not exist for that member number, the stack member uses its default interface-specific configuration.

• If an interface-specific configuration exists for that member number, the stack member uses the interface-specific configuration associated with that member number.

If you replace a failed member with an identical model, the replacement member automatically uses the same interface-specific configuration as the failed device. You do not need to reconfigure the interface settings. The replacement device (referred to as the provisioned device) must have the same stack member number as the failed device.

You back up and restore the stack configuration in the same way as you would for a standalone device configuration.

You can use the offline configuration feature to provision (to supply a configuration to) a new switch before it joins the switch stack. You can configure the stack member number, the switch type, and the interfaces associated with a switch that is not currently part of the stack. The configuration that you create on the switch stack is called the provisioned configuration. The switch that is added to the switch stack and that receives this configuration is called the provisioned switch.

You manually create the provisioned configuration through the switch stack-member-number provision type global configuration command. You must change the stack-member-number on the provisioned switch before you add it to the stack, and it must match the stack member number that you created for the new switch on the switch stack. The switch type in the provisioned configuration must match the switch type of the newly added switch. The provisioned configuration is automatically created when a switch is added to a switch stack and when no provisioned configuration exists.

When you configure the interfaces associated with a provisioned switch, the switch stack accepts the configuration, and the information appears in the running configuration. However, as the switch is not active, any configuration on the interface is not operational and the interface associated with the provisioned switch does not appear in the display of the specific feature. For example, VLAN configuration information associated with a provisioned switch does not appear in the show vlan user EXEC command output on the switch stack.

The switch stack retains the provisioned configuration in the running configuration whether or not the provisioned switch is part of the stack. You can save the provisioned configuration to the startup configuration file by entering the copy running-config startup-config privileged EXEC command. The startup configuration file ensures that the switch stack can reload and can use the saved information whether or not the provisioned switch is part of the switch stack.

Each software image includes a stack protocol version. The stack protocol version has a major version number and a minor version number (for example 1.4, where 1 is the major version number and 4 is the minor version number). Both version numbers determine the level of compatibility among the stack members.

The switches with the same Cisco IOS software version have the same stack protocol version. Such switches are fully compatible, and all features function properly across the switch stack. A device with the same Cisco IOS software version as the active switch can immediately join the switch stack.

If an incompatibility exists, the fully functional stack members generate a system message that describes the cause of the incompatibility on the specific stack members. The active switch sends the message to all stack members.

For more information, see the Major Version Number Incompatibility Among Switches procedure and the Minor Version Number Incompatibility Among Switches procedure.

You manage the switch stack and the stack member interfaces through the active switch. You can use the CLI, SNMP, and any of the supported network management applications. You cannot manage stack members on an individual device basis.