We have 9404 switch with code 17.06.05
It has two Supervisor in slots 2 and 3.
Slot 2 - 2/0/1, 2/0/2 and Slot 3 - 3/0/1, 3/0/2 are 1 gig fiber ports.
All 4 ports are in same port channel and going to upstream switch A and B where they are also in same port-channel.
Everything was working very fine till last year (was working since last few years) and one day we discovered that 3/0/1 and 3/0/2 were in an err-disable state with an error in the log.
"%UDLD-4-UDLD_PORT_DISABLED: UDLD disabled interface Te3/0/1, unidirectional link detected"
We swapped Supervisor between slot 2 and 3 but error followed to slot 2 as well. Therefore, slot 2 now has 2/0/1, 2/0/2 in err-disabled ports, while slots 3/0/1 and 3/0/2 are good.
We moved both cables from 2/0/1, 2/0/2 to 3/0/3, 3/0/4 and they worked without any issue.
This eliminated physical cable issue as we should get "UDLD_PORT_DISABLED" on 3/0/3, 3/0/4 if they really has problem.
Note: we never changed any config on switch in last few years. We have also moved cables to different ports in bad sup to
We then started troubleshooting the problem with slot 2.
From 3/0/3, 3/0/4, we moved cables to their original locations at 2/0/1, 2/0/2.
now,
slot 2 Supervisor - 2/0/1, 2/0/2 bad ports
slot 3 Supervisor - 3/0/1, 3/0/2 are good ports
We powered off the entire chassis and then turned it back on after five minutes. Unbelievably, 2/0/1 and 2/0/2 were in good condition.
Right now, slot 2 is active Supervisor while slot 3 is on standby.
After 30 minutes, we made the decision to failover Supervisor from 2 to 3.
slot 3 is now active but slot 2 - 2/0/1, 2/0/2 went to "UDLD_PORT_DISABLED" after 5 minutes.
We replaced the old Supervisor in slot 2 with a brand new one (from TAC), but the issue remained.
After all this troubleshooting, the conclusion is –
If we cold reboot chassis, slot 2 ports work fine.
If we reboot Slot 2 only or reseat, problem continue/return
If we failover any Supervisor, problem continue/return
If we move exact same cables to good Supervisor slot 3 currently, it worked without any problem.
If we move entire Supervisor to different slot, problem follow to that slot.
We think problem is either received faulty Supervisor from CISCO (which is mostly not possible) or some bug with chassis.
we have a TAC case open, I will provide you with more details when we concluded.
Has anybody, however, encountered a similar problem?
