Nexus Routing over vPC

[sutha_entc]

Hi All, 

I am running into an routing issue in Nexus environment. please help if anyone know the issue. here is the simple diagram and I put some information in the diagram also. 

here is the problem. 

USER-1 able to reach vlan 10 SVI in SW-3 but unable to reach the vlan 10 SVI in SW-4. SW-3 has the user subnet in its BGP routing table. SW-4 use OSPF via peer link. 

when I move the OSPF routing to dedicated link between SW-3 and SW-4, SW-4 still use OSPF to reach user subnet, and this time also working fine. this is normally we do. we use dedicated links for routing. but if we use layer3 peer-router, we can run the routing over peer link. but why it is not working in this case? when I shutdown the back to back vPC port-channel in SW-4, its working. 

anyone has any idea? what is wrong here? I am using version 7.0(3)i7(6)  -N9K-C9372PX-E

thanks 

[balaji.bandi]

we use dedicated links for routing. but if we use layer3 peer-router, we can run the routing over peer link. but why it is not working in this case?

 Post relevant configuration and output along with Routing table information.

check vPC best practice - when you looking to deploy layer 3 using vPC environment.

You show in the picture, you have BGP peering only with 1 Switch or both the switch in vPC ?

check BGP guide lines : As you mentioned there is only path for e-BGP - so Switch4 always need to go via SW3 - since that is where the routing learned here.

https://www.cisco.com/c/en/us/support/docs/ip/ip-routing/217099-ebgp-peering-over-vpc-on-nexus.html