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 ethernet 1/2/3 to 1/2/4 and ethernet 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 ethernet 1/2/1 to 1/2/2 and ethernet 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 ethernet 1/2/3 to 1/2/4 and ethernet 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.

    Add a new procedure:

    Add a new procedure:

Starting from release 09000, when a live stacking port becomes a data port, 
it is disabled to prevent potential L2 loops. Users must enable it before configuring stack-trunk.
  4. Note: Starting from FastIron release 09.0.00, when a live stacking port becomes a data port, it is disabled to prevent potential Layer 2 loops. You must enable it before configuring it.
    In interface configuration mode, enable the ports that will form the stacking trunk.
    ICX7250-48P Router(config-unit-1)# interface ethernet 1/2/3 to 1/2/4
ICX7250-48P Router(config-mif-1/2/3-1/2/4)# enable
ICX7250-48P Router(config-mif-1/2/3-1/2/4)# interface ethernet 2/2/3 to 2/2/4
ICX7250-48P Router(config-mif-2/2/3-2/2/4)# enable
  5. Enter the following commands to create a two-port trunk configuration on the active controller. 
    
ICX7250-48P Router(config-mif-2/2/3-2/2/4)# stack unit 1
ICX 7250(config-unit-1)# stack-trunk ethernet 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.
  6. Enter stack unit 2 configuration sub-mode on the active controller. 
    ICX 7250(config-unit-1)# stack unit 2
  7. Create a connecting two-port trunk for stack unit 2. 
    ICX 7250(config-unit-2)# stack-trunk ethernet 2/2/3 to 2/2/4
    The system performs an election and forms a stacking ring.
  8. 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 ethernet 1/2/1 1/2/2 and ethernet 2/2/1 2/2/2
Port 1/2/3 becomes a data port and is disabled to avoid potential loops.
Port 1/2/4 becomes a data port and is disabled to avoid potential loops.
stack-trunk ethernet 1/2/1 to 1/2/2 replaces stack-trunk ethernet 1/2/1 to 1/2/4
Port 2/2/3 becomes a data port and is disabled to avoid potential loops.
Port 2/2/4 becomes a data port and is disabled to avoid potential loops.
stack-trunk ethernet 2/2/1 to 2/2/2 replaces stack-trunk ethernet 2/2/1 to 2/2/4
ICX7250-48P Router(config-unit-1)#interface ethernet 1/2/3 to 1/2/4
ICX7250-48P Router(config-mif-1/2/3-1/2/4)#enable
ICX7250-48P Router(config-mif-1/2/3-1/2/4)#interface ethernet 2/2/3 to 2/2/4
ICX7250-48P Router(config-mif-2/2/3-2/2/4)#enable
ICX7250-48P Router(config-mif-2/2/3-2/2/4)#stack unit 1
ICX7250-48P Router(config-unit-1)# stack-trunk ethernet 1/2/3 1/2/4
ICX7250-48P Router(config-unit-1)# stack unit 2
ICX7250-48P Router(config-unit-2)# stack-trunk ethernet 2/2/3 2/2/4
ICX7250-48P Router(config-unit-2)# exit
ICX7250-48P Router(config)#
ICX7250-48P Router(config)# show running-config
Current configuration:
!
ver 09.0.00
!
stack unit 1
  module 1 icx7250-48p-poe-port-management-module
  module 2 icx7250-sfp-plus-8port-80g-module
  priority 128
  stack-trunk ethernet 1/2/1 to 1/2/2
  stack-trunk ethernet 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 ethernet 2/2/1 to 2/2/2
  stack-trunk ethernet 2/2/3 to 2/2/4
stack enable
stack mac 609c.9f99.3f80
!
ICX7250-48P Router(config)# write memory
Parent topic: Configuring Two-unit Stack Linear-topology Trunks