layer 3 peer-router command doubt

[irenof]

Hi all,

I have to configure two N9Ks with a VPC peer-link. Each device also establish BGP sessions with a CE, as shwon in the figure

Each device has its own /30 SVI to the CE.

My question is, should I insert the commandlayer 3 peer-router in the VPC domain configuration? I suppose no, since each session has its own /30 SVI, but the trunk of the PO has both the VLAN, so I could be possible that the has alg chooses other leg. For example BGP session from CE to A passes through B. And B sees SVI MAC A with G flag and decrements TTL..

Am I saying soething wrong?

[MHM Cisco World]

no need 3 peer-router if CE connect to each NSK via different SVI IP.

MHM

[irenof]

Hi, thank you for your reply. This clarify my doubt.

After posted the question, I came accross an other doubt:

I have EBGP mhop between VRF A and VRF B through a FW. Each device has SVI A and B with a /29. VRF A on device A (10.10.10.2) want to establish a BGP session to VRF B on device B (11.11.11.3). Could happen that the FW chooses the left leg to send packet to SVI B? In this case, A should route the packet to B.

[MHM Cisco World]

no need multihop ebgp,
FW have single hop ebgp to each NSK via one SVI 
and between NSK you can run ibgp 

no need to make FW have multihop ebgp with both NSK

MHM

[irenof]

Maybe I was not clear, sorry. I must (requirements) establish a ebgp session from VRF A on device A to VRF B on device B. This session must pass through the FW (I have static routes for this). Both devices has SVI A and B /29, with own IP address. My question is if the FW could route the packet to SVI B device B address via device A. Thanks

[MHM Cisco World]

no need also, add new SVI for config ibgp between two NSK instead of depend on L2/L3 path which pass through FW

you can use vpc vlan or non-vpc vlan for ibgp between two NSK

MHM

[irenof]

The decision to pass thourgh via FW is mandatory. I cannot change it. I am migrating to Nk9s devices with VPC peer-link and I am dealing with this situations, so I have some doubts about L3 routing with VPC

Thanks

[MHM Cisco World]

Let me check it

MHM

[irenof]

Hi @MHM Cisco World, I made a lab in eve-ng and for the firewall I have to add the layer3 perr-router command. Also the devices prints the warning when I try to establish a BGP session. The warning says to add the command to solve a issue (I cannot exactly copy it now)