4500x VSS to 6807 VSS on L3 pagp Port Channel

[Michael Voity]

Hello, 

Not sure if we hit a bug or a caveat of software with this situation.

We have a 6807 vss pair that has a Layer 3 pagp Port channel to a 4500x vss pair.

When we converted over to this L3 port channel, we had reachability issues across the Port-channel from random devices.  One device in the same subnet could connect when another device in the same subnet couldn't.  We then realized that it was possible the L3 port-channel was the cause, so we disabled one leg, and then everything was back to normal and reachability was restored for all devices.

To correct this, we disabled 1 leg of the port channel  and everything went back to normal.    the previous normal was a pair of 3750's which we needed to remove.

Our thinking is that VSS pair to VSS pair on a L3 port channel is not supported.   We haven't tried converting the port channel from pagp to lacp, ran out of time in window.

Ideas?

code levels:

4500x =  03.06.07.E

6807 = 12.2(50r)SYS3

-Mike

[Scott Hodgdon]

Michael,

L3 Port Channel between VSS pairs is supported. The key is to make sure that all VSS members are dual-homed, so it should be 4 links in the port channel. 

You are running code that has reached End of Support (12.2(50)SY) as of July 2017 (see https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-6500-series-switches/eol_c51-698004.html ).

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group

[Michael Voity]

Scott,

Thanks for the reply, 

My 6807 is actually - 15.1(2)SY5,  I cut and pasted the bootstrap...  

-Mike

[Mark Malone]

Hi
I only see 1 bug for pagp in that train and it says its resolved in earlier release , doesnt mean you didn't hit something though may be unknown , i dont have a 68 but i have 6509E VSS to 45X VSS in campus core to dist setup and it works well with LACP , worth a shot , on mode can cause issues sometimes in VSS from my experience so i would avoid that if possible

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-1SY/release_notes.html