vPC with Nexus and Layer 3 router

[Network Pro]

Hi

Hi, 

we have vPC to router 1 and Router 2 via l3 port-channel on both cores. If i do a sh ip eigrp topology table I see only Nexus 2 (not Nexus 1) - is this normal?

Nexus 1            -        Nexus 2

     \ vPC |             /     \          /

       \                   /       \         /

|---Router1 --|   |---Router 2----|

[M02@rt37]

Hello @Network Pro,

This is because the vPC is configured as an active-active setup, where Nexus 1 and Nexus 2 share the forwarding load. Therefore, the EIGRP neighbor adjacency formed with the routers will be established on both Nexus switches. However, only one Nexus switch will actively advertise the routes to the EIGRP neighbors, while the other Nexus switch will act as a standby.

To confirm the EIGRP neighbor adjacency between Nexus 1 and the routers, you can check the output of the "show ip eigrp neighbors" command on both Nexus switches. This command will display the active EIGRP neighbors on each switch.

[MHM Cisco World]

Peer-gateway and layer 3 router peer 

These two commend can help you

[paul driver]

Hello
I beleive @MHM Cisco World  is on the right track - review this post from Hall of fame and networking guru peter paluch - here

[Network Pro]

Thanks for all your replies

we do have all these commands - please see our config below

I do see eigrp neighbour from both upstream routers however if I do a sh ip route to another vlan that is behind the core then I see only 1 route

Core 1

vpc domain 10
peer-switch
role priority 30000
system-priority 1024
peer-keepalive destination 7.1.1.2 source 7.1.1.1
peer-gateway
layer3 peer-router
ip arp synchronize

Core 2

vpc domain 10
peer-switch
role priority 32000
system-priority 1024
peer-keepalive destination 7.1.1.1 source 7.1.1.2
peer-gateway
layer3 peer-router
ip arp synchronize

version 10.2(3) Bios:version 05.45

interface port-channel5
switchport
switchport mode trunk

Upstream router

interface Port-channel7.255
description WAN-Transit
encapsulation dot1Q 255
ip address 10.1.255.20 255.255.255.0
service-policy input QoS-Mark
end

interface Port-channel1
no ip address
negotiation auto

sh ip route 10.1.255.0
Routing entry for 10.1.255.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp xxx, bgp xxxxx
Advertised by bgp xxxxx
Routing Descriptor Blocks:
* directly connected, via Port-channel1.255
Route metric is 0, traffic share count is 1
sh ip route 10.1.249.1
Routing entry for 10.1.249.0/24
Known via "eigrp 100", distance 15, metric 3072, precedence routine (0), type internal
Redistributing via eigrp xxx, bgp xxx
Advertised by bgp xxxxx route-map REDRISTRIBUTE
Last update from 10.1.255.12 on Port-channel1.255, 05:45:12 ago
Routing Descriptor Blocks:
* 10.1.255.12, from 10.1.255.12, 05:45:12 ago, via Port-channel1.255
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

Shouldnt i be seeing 10.1.255.11 which is CORE 1? (10.1.255.11 and .12 are SVI on core 1 so as 10.1.249.11 and .12