Nexus 3000 loop-detect and Port-Channel

[Surgeon]

Hi all.

I am newbie in Nexus. Please help me to understand loop-guard behavior with Port Channel in non-vPC mode for Nexus 3000.

According to the manual, loop-guard blocks port with lower index. Based on SNMP Port-Channel has lower index then even eth 1/1. Does it mean that Po1 will be blocked by loop-guard if let say mac-move between Po1 and eth1/1 occurs?  If yes, then is there any way to prevent Po1, which is uplink , from being blocked? Thanks

 

[SlawekG]

Did you found how to resolve this issue ?

I have same problem. Po1 is used for Uplink between switches and rest of Eth is downlinks. In any case of loop it's turning off my main Uplink.

[M02@rt37]

Hello @Surgeon,

In non-vPC mode, when loop guard is enabled on a Nexus 3000 switch, it will block the port with the lower port index if it detects a loop. This means that if a mac-move occurs between Po1 and Eth1/1, and Po1 has a lower index than Eth1/1, then Po1 will be blocked by loop guard.

To prevent the uplink port from being blocked, you can configure loop guard on a per-port basis. This is done by configuring the "loopguard default" command on the interface that you want to protect from being blocked. This will disable loop guard on that specific interface, allowing it to remain operational even if a loop is detected.