ISL between 2960S and 2960X stacks

[marcus.wiedemann]

Dear all,

I hope to find some help or hints in this matter.

We are running two compute clusters, each having a separate stack configured. In site A, we have 3x C2960S (f/w 12.2) in a stack, in site B we have 6x C2960X (f/w 15.2) in a stack. The compute cluster in site A is running in 10.19.0.0/16, the one in site B in 10.19.2.0/16.
For the nodes in site A, we have the provisioning interfaces connected to VLAN 2 (interface 10.19.2.250/16) and the management interfaces to VLAN 3 (interface 10.20.2.250/16). In site B all ports are still configured into the default VLAN 1 (interface 10.19.0.250/16).

The goal is to make the nodes visible to each other as we have centralized components that must be visible to both clusters (like filesystems etc.).

I have already configured an Etherchannel of 4x RJ45 Gigabit in between these two stacks. All ports are in status Active, so on first view, LACP seems to work fine.
But when it comes to routing, I'm a bit in trouble as the C2960S switches do not offer the ip routing command. I've read about switching to the SDM template lanbase-routing, so I guess after switching the routing command should be available.
Regarding this, I have some questions:

a) Does switching the SDM template affect the configuration?
I know that I need to reload the C2960S stack in order to activate/load the lanbase-routing template (first need to find a downtime for this...). But is there a need to re-configure settings after switching?

b) Is there a way to build an ISL in between these two stack w/o the need for additional routing? If yes, do we need to upgrade the firmware of the C2960S' to be able to configure ISL?
I've built some ISLs in the past, mainly based on IBM's Rackswitches or Mellanox 40 GbE switches - in each scenario, both ISL members were of the same type and running the same f/w...

Thank you very much for any assistance!

Best regards
Marcus

[Philip D'Ath]

You whole IP subnetting and VLAN design is messed up.  Each VLAN should have a non-overlapping subnet assigned.

You could consider changed all your /16's to /24's or keep your /16 and put everything into one VLAN.

I would trunk everything to the 2960-X's.  As long as they aren't "lan lite" you have basic layer 3 routing available (just use "ip routing" to enable routing on them).

Personally I think the selection of 2960-X's was not the best choice.  You should really be looking at a 4507 or better.  You can also get much better up time on a 4507 if you use dual supervisors thanks to features like ISSU.

At a minimum, you should probably be using Cisco 3850's.