VPC peers as OSPF/BGP neighbours

[velo84]

I've been reading the following document:

https://www.cisco.com/c/en/us/support/docs/ip/ip-routing/118997-technote-nexus-00.html

I would like to peer a pair of firewalls over vPC with OSPF to a pair of Nexus 9ks, I'm happy with this and I see that there is the feature 'layer3 peer-router' which should be used in this instance.

My question is I want to peer the two Nexus switches together as OSPF/BGP neighbours. How should this be done? Can I create a dedicated VLAN/SVI on each switch and allow this VLAN across the peer across the peer-link and use that for peering or do I need to plug in a new dedicated cable for this? (In the above link the Cisco diagram shows a dedicated Layer3 link, is this for the peering between the two vPC peers?)

Thanks

[Christopher Hart · Accepted solution]

Hello!

You can form a routing protocol adjacency (OSPF, EIGRP, BGP, IS-IS, RIP, etc.) between both vPC peers over the vPC Peer-Link on all NX-OS software releases without any special configuration (such as layer3 peer-router) under the vPC domain. There is no need for a dedicated Layer 3 link between both vPC peers to accomplish this.

As such, you can use an SVI in any VLAN that is trunked across the vPC Peer-Link to form this routing protocol adjacency. You can create a new VLAN/SVI on both vPC peers dedicated to this purpose, or you can use a handful of existing VLANs/SVIs on both vPC peers to establish multiple redundant adjacencies (such that an event in a single VLAN does not affect all routing protocol adjacencies.) Both are valid design options, depending on your environment and the amount of additional control plane overhead that is deemed acceptable in your environment.

I hope this helps - let me know if you have any additional questions! Thank you!

-Christopher

[velo84]

This is perfect, thank you very much Chris.