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 ring-topology stack, 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 8200 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 ring-topology stack.

Enter global configuration mode on the active controller.
```
ICX8200-24P Router# configure terminal
```

Enter stack unit 1 configuration sub-mode on the active controller.
```
ICX8200-24P Router(config)# stack unit 1
```

Enter the following command to modify the configuration of the live trunk.

ICX8200-24P Router(config-unit-1)# multi-stack-trunk ethernet 1/2/1 to 1/2/2 and ethernet 2/2/1 to 2/2/2
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
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

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.

Note: Starting from FastIron release 09.0.10a, 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.
```
ICX8200-24P Router(config-unit-1)# interface ethernet 1/2/3 to 1/2/4
ICX8200-24P Router(config-mif-1/2/3-1/2/4)# enable
ICX8200-24P Router(config-mif-1/2/3-1/2/4)# interface ethernet 2/2/3 to 2/2/4
ICX8200-24P Router(config-mif-2/2/3-2/2/4)# enable
```

Enter the following commands to create a two-port trunk configuration on the active controller.
```
ICX8200-24P Router(config-mif-2/2/3-2/2/4)# stack unit 1
ICX8200-24P Router(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.

Enter stack unit 2 configuration sub-mode on the active controller.
```
ICX8200-24P Router(config-unit-1)# stack unit 2
```

Create a connecting two-port trunk for stack unit 2.
```
ICX8200-24P Router(config-unit-2)# stack-trunk ethernet 2/2/3 to 2/2/4
```
The system performs an election and forms a ring-topology stack.

Enter the write memory command to save the configuration.

ICX8200-24P Router(config-unit-2)# exit
ICX8200-24P Router(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 trunk to a ring-topology stack and includes system output.

ICX8200-24P Router# show stack
T=13m58.5: alone: standalone, D: dynamic cfg, S: static
ID   Type          Role    Mac Address    Pri State   Comment
1  S ICX8200-24P   active  c0c5.207c.26ec 128 local   Ready
2  S ICX8200-24P   standby c0c5.207e.daea   0 remote  Ready

    active       standby
     +---+        +---+
     | 1 |2/1==2/1| 2 |
     +---+        +---+
Standby u2 - protocols ready, can failover
Role history: N: standalone, A: active, S: standby, M: member
U1: N->A

Current stack management MAC is c0c5.207c.26ec
ICX8200-24P Router# show running-config
Current configuration:
!
ver 10.0.00_b324T253
!
stack unit 1
  module 1 icx8200-24p-port-management-module
  module 2 icx8200-4-sfp-plus-port-100g-module
  priority 128
  stack-trunk ethernet 1/2/1 to 1/2/4
stack unit 2
  module 1 icx8200-24p-port-management-module
  module 2 icx8200-4-sfp-plus-port-100g-module
  stack-trunk ethernet 2/2/1 to 2/2/4
stack enable

stack mac c0c5.207c.26ec
!
hitless-failover enable
... snipped

ICX8200-24P Router# configure terminal
ICX8200-24P Router(config)# stack unit 1
ICX8200-24P Router(config-unit-1)# multi-stack-trunk ethernet 1/2/1 to 1/2/2 and ethernet 2/2/1 to 2/2/2
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
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
ICX8200-24P Router(config-unit-1)# interface ethernet 1/2/3 to 1/2/4
ICX8200-24P Router(config-mif-1/2/3-1/2/4)# enable
ICX8200-24P Router(config-mif-1/2/3-1/2/4)# interface ethernet 2/2/3 to 2/2/4
ICX8200-24P Router(config-mif-2/2/3-2/2/4)# enable
ICX8200-24P Router(config-mif-2/2/3-2/2/4)# stack unit 1
ICX8200-24P Router(config-unit-1)# stack-trunk ethernet 1/2/3 to 1/2/4
ICX8200-24P Router(config-unit-1)# stack unit 2
ICX8200-24P Router(config-unit-2)# stack-trunk ethernet 2/2/3 to 2/2/4
ICX8200-24P Router(config-unit-2)# exit
ICX8200-24P Router(config)# write memory

Automatic copy to member units:  2
Flash Memory Write (8192 bytes per dot)
.
Write startup-config done.
Copy Done.
ICX8200-24P Router(config)# show stack
T=18m54.4: alone: standalone, D: dynamic cfg, S: static
ID   Type          Role    Mac Address    Pri State   Comment
1  S ICX8200-24P   active  c0c5.207c.26ec 128 local   Ready
2  S ICX8200-24P   standby c0c5.207e.daea   0 remote  Ready

    active       standby
     +---+        +---+
 =2/3| 1 |2/1==2/1| 2 |2/3=
 |   +---+        +---+   |
 |                        |
 |------------------------|
Will assign standby in 24 sec due to all ready

Standby u2 - protocols ready, can failover
Role history: N: standalone, A: active, S: standby, M: member
U1: N->A

Current stack management MAC is c0c5.207c.26ec

Building a Stack

Changing a Live Linear-topology Trunk to a Ring