ISL is out-of-sync

Solution 1

Cause

Mismatch with the ISL version or switch platform or both.

Action

Run the show vsx status command.

In the following example, the ISL channel is shown as in-sync; however, if the ISL channel was not in-sync, a different status would be provided.

switch# show vsx status
VSX Operational State
---------------------
  ISL channel             : In-Sync
  ISL mgmt channel        : operational
  Config Sync Status      : in-sync
  NAE                     : peer_unreachable
  HTTPS Server            : peer_unreachable

Attribute           Local                       Peer
------------        --------                    --------
ISL link            1/1/43                      1/1/43
ISL version         2                           2
System MAC          48:0f:cf:af:70:84           48:0f:cf:af:c2:84
Platform            8320                        8320
Software Version    10.0x.xxxx                  10.0x.xxxx
Device Role         primary                     secondary

If there is an ISL version mismatch, update the software so the ISL version is the same on the local and peer VSX switch.
If the switches have mismatching platforms, create an ISL link that connects two VSX switches with the same platform.

Solution 2

Cause

The role is not configured on any of the VSX switches or the same role is configured on both VSX switches.

Action

Run the show vsx status command.
If the roles are set incorrectly, the command displays the role inconsistent status.
Set the roles correctly so that one of the VSX switches has the primary role and the other switch has the secondary role. To set a switch role, enter the role {primary | secondary} command.

Solution 3

Cause

The ISL interface is down on any one switch in the VSX pair.

Action

Check ISL state and ISL link status by entering:

switch# 
		  show vsx status inter-switch-link

In the following example, the ISL state and link status are shown as in-sync and up; however, if the ISL interface is down, a different status would be provided.

switch# show vsx status inter-switch-link
State                     : In-Sync
Link Status               : up
Mgmt state                : operational

Inter-switch link Statistics
----------------------------
Hello Packets Tx          : 4572
Hello Packets Rx          : 4573
Data Packets Tx           : 80634
Data Packets Rx           : 80637
Mgmt Packets Tx           : 25946
Mgmt Packets Rx           : 25167
Mgmt Packet Drops         : 0

Re-enable the ISL interface by going to that interface context and entering no shutdown:
```
switch(config)# interface 1/1/1
switch(config-if)# no shutdown
```