This article describes one of the reasons why we may get ISL timing out error messages in logs, although there may not be any impact.

Scope

FortiSwitch.

Solution

After typing this command, this result can occur:

# execute log display
595 logs found.
10 logs returned.

1: 2022-10-18 20:33:22 log_id=0106009008 type=event subtype=switch_controller pri=notice vd=root msg="FortiLink: ISL timing-out for trunk(8EFTF18XX0001-0) member port-num(24) port24 did not receive ISL pkt for(30) sec"

2: 2022-10-18 20:33:22 log_id=0106009008 type=event subtype=switch_controller pri=notice vd=root msg="FortiLink: ISL timing-out for trunk(8EFTF18XX0001-0) member port-num(23) port23 did not receive ISL pkt for(30) sec"

3: 2022-10-18 20:33:21 log_id=0106009008 type=event subtype=switch_controller pri=notice vd=root msg="FortiLink: ISL timing-out for trunk(8EFTF18XX0001-0) member port-num(24) port24 did not receive ISL pkt for(30) sec"

Possible reason to see this issue is:

1. When it is manually enabled mclag-icl on the trunk and,
2. default-auto-mclag-icl lldp profile is pushed from the FortiGate to the ICL ports.

Note:

In the latest versions, it is recommended to follow point2.

It will be required to launch a maintenance window to do the following activity.

To avoid this issue, get the console to both FortiSwitch and delete the mclag-icl trunk.

An example on FortiSwitch will be: S248EFTF18XX0075 and see the following trunk configured:

# show switch trunk
# config switch trunk
edit "8EFTF18XX0001-0"
set mode lacp-active
set auto-isl 1
set mclag-icl enable 

Then delete the trunk in both FortiSwitches.

On S248EFTF18XX0075:

# config switch trunk
delete 8EFTF18XX0001-0"
next
end

Similarly, delete the trunk on S248EFTF18XX0001 as well.

Now, since default-auto-mclag-icl lldp profile is mapped from the FortiGate to the ICL ports, the FortiSwitches will form a trunk with a new name ‘_FlInK1_ICL0_’.

The post Solved: How do I fix ISL timing-out on mclag-icl trunk? appeared first on PUPUWEB - Information Resource for Emerging Technology Trends and Cybersecurity.