Changing a Live Linear-topology Trunk to a Ring

The ICX system performs numerous checks to block commands that could break a live stack. However, the checks have limitations and may not catch all potential breaks. Therefore, you should verify the physical connections on the stack before using the multi-stack-port or multi-stack-trunk command.

You can use the show stack connection command to check the physical connections of stacking ports (data port connections are not shown).

Suppose the physical connections displayed only two-port trunk connections on each unit, for example, ports 1/2/3 to 1/2/4 and 2/2/3 to 2/2/4. To change the existing live configuration to a stacking ring, the multi-stack-trunk 1/2/3 to 1/2/4 and 2/2/3 to 2/2/4 command is required.

The following example uses an ICX 7250 two-unit stack with a linear-topology trunk between ports 1/2/1 to 1/2/4 and 2/2/1 to 2/2/4.

Complete the following steps to convert the linear-topology trunk to a stacking ring.

  1. Enter global configuration mode on the active controller. 
    ICX 7250# configure terminal
  2. Enter stack unit 1 configuration sub-mode on the active controller. 
    ICX 7250(config)# stack unit 1
  3. Enter the following command to modify the configuration of the live trunk. 
    ICX 7250(config-unit-1)# multi-stack-trunk 1/2/1 to 1/2/2 and 2/2/1 to 2/2/2
    Note: If there is no physical link on port 1/2/1 or 1/2/2, use the command multi-stack-trunk 1/2/3 to 1/2/4 and 2/2/3 to 2/2/4.
    The system removes ports 1/2/3, 1/2/4, 2/2/3, and 2/2/4 from the linear-topology trunk. They become data ports.
  4. Enter the following command to create a two-port trunk configuration on the active controller. 
    ICX 7250(config-unit-1)# stack-trunk 1/2/3 to 1/2/4
    Note: The stack-trunk command is used in this case because ports 1/2/3 and 1/2/4 have become data ports and are not considered live stacking ports. The same applies to the ports on unit 2 in subsequent steps.
  5. Enter stack unit 2 configuration sub-mode on the active controller. 
    ICX 7250(config-unit-1)# stack unit 2
  6. Create a connecting two-port trunk for stack unit 2. 
    ICX 7250(config-unit-2)# stack-trunk 2/2/3 to 2/2/4
    The system performs an election and forms a stacking ring.
  7. Enter the write memory command to save the configuration. 
    ICX 7250(config-unit-2)# exit
ICX 7250(config)# write memory

Note: The preceding steps require the operator to enter commands to form trunks from data ports in steps 6 and 7.

The following example summarizes the conversion of a two-unit stack linear-topology ring to a stacking ring topology and includes system output. 

ICX7250-48P Router# configure terminal
ICX7250-48P Router(config)# stack unit 1
ICX7250-48P Router(config-unit-1)# multi-stack-trunk 1/2/1 1/2/2 and 2/2/1 2/2/2
stack-trunk 1/2/1 to 1/2/2 replaces stack-trunk 1/2/1 to 1/2/4
stack-trunk 2/2/1 to 2/2/2 replaces stack-trunk 2/2/1 to 2/2/4

ICX7250-48P Router(config-unit-1)# stack-trunk 1/2/3 1/2/4
ICX7250-48P Router(config-unit-1)# stack unit 2
ICX7250-48P Router(config-unit-2)# stack-trunk  2/2/3 2/2/4
ICX7250-48P Router(config-unit-2)# exit
ICX7250-48P Router(config)#

ICX7250-48P Router(config-unit-1)# show running-config
Current configuration:
!
ver 08.0.90
!
stack unit 1
  module 1 icx7250-48p-poe-port-management-module
  module 2 icx7250-sfp-plus-8port-80g-module
  priority 128
  stack-trunk 1/2/1 to 1/2/2
  stack-trunk 1/2/3 to 1/2/4
stack unit 2
  module 1 icx7250-48p-poe-port-management-module
  module 2 icx7250-sfp-plus-8port-80g-module
  stack-trunk 2/2/1 to 2/2/2
  stack-trunk 2/2/3 to 2/2/4
stack enable
stack mac 609c.9f99.3f80
!
ICX7250-48P Router(config-unit-1)# exit
ICX7250-48P Router(config)# write memory
Parent topic: Configuring Two-unit Stack Linear-topology Trunks