Switch is ignoring enable group sharing and it's causing a loopback

[Arison_Mercado]

Hi everyone

I have an issue with one of my stacks where it's acting like a loopback issue. For example, in this case I have ports 1:41 and 14:2 on switch 1 grouped and Uplinked to ports 1:53, 6:53 which are also grouped on switch 2. Now this configuration has been the same since we first deployed these switches and only recently I've been losing connectivity on switch 2. The only way to temporary resolve the issue is to disable port 1:42 on Switch 1. In addition, I also have elrp excluded on both ends of the uplinks. If anyone has any suggestions please let me know.

Thanks

[Sumit_Tokle]

which switch? is it X460 with XGM module.

[Tony_Steed]

I appreciate you keeping me in the loop... This lends itself to my earlier reference to a potentially defective phy. I'm glad it worked out for you.

Tony

[Arison_Mercado]

Hi Tony,

Thank you for your input, I will definitely use that for troubleshooting if this occurs again. Also, I was able to contact TAC support and what we identified is that when the grouping ports were active on both ends, one of them would stay on a ready state causing the switch to lose some network connectivity. So the engineer, conducted a remote session and reviewed the "debug" results and came to the conclusion that one of the switches on the stack is in fact defective.

[Tony_Steed]

It doesn't sound like a known issue... It's more likely a configuration issue. I would confirm the following:

- show port sharing (verify the LAG configuration is consistent on both sides of the link)

- show elrp (verify that no loop condition exists on any of the VLANs); sift through show config and verify that interconnect LAG ports are in fact excluded from ELRP)

- Show log match : attempt to discern when the interfaces go off-line and what corresponding changes may be causing the event(s); don't rule out a phy problem (i.e. physical layer issue with optics - if applicable, patch cables, etc.)

We use ELRP in conjunction with LAG ports in many scenarios with both current and superannuated firmware versions and have never encountered any issues