Troubleshooting an interface in a port-channel

[Kevin Smith]

Question……I’m trying to troubleshoot a downed interface that is part of a port-channel….my question is, should I remove the interface from the port-channel to troubleshoot it….currently when I’m troubleshooting the port in the port-channel the other interface goes down?  The devices are 3750 to a 3850?...also is there a good reference doc on this?

[Reza Sharifi]

since the physical port is already down, you can simply take it out of the portchannle, do your troubleshooting and when the interface is back up added it to the portchannel again. This way you isolate the port and don't have to worry about the portchannel interface.

HTH

[Kevin Smith]

That’s what I’m thinking also……Just curious should that be standard practice when troubleshooting an issue like this?

[Reza Sharifi]

I don't think there is such standard, but it is probably a good practice.

[Florin Barhala]

Quick question, when having a port-channel formed on 2 Gigabit interfaces and I remove one Gigabit interface from the port-channel, will STP immediately block it? I mean STP will always choose a port-channel over one interface although both provide the same BW?

kdsmith01 for your question I suggest you take good care of STP if you remove that interface, in case it will link-up to avoid any small outage cause by STP convergence.

[Kevin Smith]

thank u

[Kevin Smith]

Thank u

[Leo Laohoo]

What kind of link is this?  Is a copper port?  You can try running a TDR if the port is copper.  

1. Command:  test cable tdr interface <BLAH>;
2. Wait for 5 to 7 seconds; 
3. Command:  sh cable tdr interface <BLAH>; and
4. Post the output to #3.

[Kevin Smith]

>What kind of link is this?  copper (Cat5e)
>Is a copper port?  sfp

!

Will try your suggestion..thanks
 

[Leo Laohoo]

Copper SFP doesn't support the TDR. 

You'll need to temporarily move the copper link to a dedicated copper port (GigabitEthernet port preferred) for testing.

[Kevin Smith]

Interesting…..ok thanks I will note that.

[Leo Laohoo]

How to use Time-Domain Reflectometer (TDR)

[Kevin Smith]

> Interesting Thanks for that link