Re: Cross stack port aggregation options for 4500X and 2960X stacks...and even linux too

lonelyadmin · ‎04-30-2021

I have 2 4500X VSS stacks (4 switches total) connected by a 4 port trunk...nothing exciting, it works fine. I need to uplink a few 2960X's (also stacked) and I'm looking for documentation on if I should split the links between the stacks or have the individual port-channels connected to a single switch or switch stack. Seems like connecting to each stack would make the STP gods angry...not sure.

Also, I need to connect a linux box bonded interface to both 4500X stacks. Any documentation (switch side) on that as well?

All of this is for FT/redundancy, not so much for any active/active balancing, though that is fine too.

Update:

To be clear, I have 2 separate 4500X stacks, each consisting of 2 switches, and a stack consisting of 2 2960X switches. I'd like to have connections to both VSS stacks from all 2960X stacks. So each 2960X stack would have links to each VSS stack.

VSS Stack01

4500x-vss01-sw01

4500x-vss01-sw02

VSS Stack02

4500x-vss02-sw01

4500x-vss02-sw02

2960X stack

2960X-stack01-sw01

2960X-stack01-sw02

So with the switches above, 2960X-stack01-sw01 would connect to 4500x-vss01-sw01 and 4500x-vss02-sw01. 2960X-stack01-sw02 would connect to 4500x-vss01-sw02 and 4500x-vss02-sw02.

If anyone knows of an online free tool for drawing up diagrams that would aid posts like this, please let me know!

Reza Sharifi · ‎04-30-2021

Also, I need to connect a linux box bonded interface to both 4500X stacks. Any documentation (switch side) on that as well?

For the Linus box, connect 2 ports to one of the sets of VSS switches (one to each 4500x) and use LACP or mode "on" for bonding. Linux should support both.

As for the 2960x stack connect the stack to one set of VSS as well. The options are LACP, and mode "on" as well. LACP usually works well. Once configured verify with "sh etherchannel summary" command.

2960x-1-----VSS-4500-1

2960x-2-----VSS-4500-2

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4500/12-2/53SG/configuration/config/channel.html

HTH

lonelyadmin · ‎05-03-2021

Hey Reza!

Sorry, I don't think I was clear in my OP. I have 2 4500-X VSS stacks. I'm trying to split the uplinks between the stacks. I've drawn up a quick and ugly diagram of what I'm trying to do.