Router redundancy to 3850 stack

[roger perkin]

I have a requirement to provide the highest level of redunancy between a 3850 stack and 2 x 3925 routers

The routers both have a 4 port switch card and the original thought was to run 2 x L3 port channels to the switch stack,

But I have discovered this is not supported.

I am looking for suggestions on the best way to implement redundant connections between two routers and a 3850 stack.

I suppose the principle is the same for 1 / 2 or 3 routers.

Each router will be peering iBGP to the 3850 stack,

Are there any best practise Cisco designs for this?

Diagram below

Many Thanks

[Jon Marshall]

Roger

I think the simplest thing with 2 interfaces per router is to connect each interface to a different switch as you have done in your diagram and run routed ports between the stack and the routers. So each separate link has it's own /30 subnet and if  a switch in the stack fails you still have connections to both routers.

Jon