Port-VLAN inconsistency across upstream switches
When a FEX is dual-homed to a pair of upstream switches, each of those switches will have a configuration for the ports on the FEX. By default, these are NOT automatically kept in step (although something called configuration synchronization can do this, which I'll go over later as I've been looking at that too).If the ports are configured identically on both switches, everything is hunky dory:
n5k-top(config)# int e101/1/3
n5k-top(config-if)# switchport access vlan 808
n5k-bottom(config)# int e101/1/3
n5k-bottom(config-if)# switchport access vlan 808
n5k-top# show int e101/1/3 status
--------------------------------------------------------------------------------
Port Name Status Vlan Duplex Speed Type
--------------------------------------------------------------------------------
Eth101/1/3 -- connected 808 full a-1000 --
However, if one of the switches has a different configuration, the port becomes inactive:
n5k-bottom(config)# int e101/1/3
n5k-bottom(config-if)# switchport access vlan 812
n5k-bottom# show int e101/1/3 status
--------------------------------------------------------------------------------
Port Name Status Vlan Duplex Speed Type
--------------------------------------------------------------------------------
Eth101/1/3 -- inactive 812 full auto --
This error can be explained with the "show int ... status err-vlans" command:
n5k-bottom# show int e101/1/3 status err-vlans
--------------------------------------------------------------------------------
Port Name Err-Vlans Status
--------------------------------------------------------------------------------
Eth101/1/3 -- 812 Vlan is not
configured on
remote vPC
interface
It doesn't show up in the verbose show int command output, which seems a bit of an omission.
Once corrected, the port immediately springs back into life.
