Etherchannel Port Failure C9500 to C9200L

[pinko]

Hi. We have a 2 switch core stack and a stack of 4 access switches connected together over 2 etherchannel links but one of the links has dropped and we don't know why. Interfaces on both sides are showing as down, down(notconnect) 

• Core - C9500-16X
• Access - C9200L-48P-4X
• SFP adapters on both switches - SFP-10GBase-SR

Configuration for the core switch side interface:

interface te2/0/3

switchport trunk native vlan 105

switchport trunk allowed vlan 10,20,30,40,105

switchport mode trunk

channel-group 2 mode active

Configuration for the access switch side interface:

interface te2/1/1

switchport trunk native vlan 105

switchport trunk allowed vlan 10,20,30,40,105

switchport mode trunk

channel-group 1 mode active

We have reseated both SFP adapters, changed cables between SFP port and fiber tray, done a shut/no shut but still nothing. This equipment is brand new and has only been installed for a few months, and this is the first issue to crop up. The other link in the etherchannel is working fine with similar settings. I was going to add another pair of ports to the etherchannel and move the SFP adapters to new ports just to rule out it being an interface issue. Before doing that (I don't have physical access to the switch) I'd like to get people's thoughts. Thanks.

[balaji.bandi]

Since its Multi-Mode - you can check the Lights (on the port side where SFP module installed) also on other side Fibre end you should see the light too. If that is no present then this is more Looks like Layer1 issue.

If the Lights you able to see then , make sure the Fibre light going on right place - TX and RX.

If any where you dont see Light, then you know the Interface may be bad or faulty, the next option is configure new port and check.

Note : you can do other test - remove port from port-channel ( try to give Loop and see if the port come up both the sides).

Always check the Logs there may be some indication logs show what is wrong ?

[M02@rt37]

Hello @pinko 

Please share the IOS version of C9500 et C9200.

[marce1000]

               - Why do you have two different channel-group numbers here ?

 M.

[MHM Cisco World]

can you share 

show udld 
MHM