BGP peering over two VPC paths in L3out interface profile

[irenof]

Hi all, I have the following situation:

I want to create an L3out (SVI) and add a BGP peering. Since the SVI consists of both the 2 VPCs I add a new path to the Interface profile of the L3Out, with the same ip addressing scheme.

My problem is how to create the BGP peering. I have to options:

1) By leaf loopback. Not the focus of this thread

2) Using the physical interface of the SVI (10.0.0.0/29). To do this I have in some way to "bind" the BGP peer to one path of the interface profile, e.g VPC20. But what about VPC10? 

As a try I created the same peering under both the path and it resulted in a double configuration in BGP CLI view. Deleting the peering under VPC10, also the BPG configuration clears one part. From CLI point-of-view all should work, but:
1) I am not able to test this

2) what happens if VPC20 fails? Will the BGP session remain UP thanks to the VPC20? 

I do not like the GUI view, where the BGP peering is binded with the path.

Am I reasoning wrong?

Thanks,

Irenofe

[irenof]

The test I performed does not use VPC, but only single interfaces. I just tested configuring a BGP peer profile under the interface that is not connetected to the router. I think that it should work also in VPC context, but at the moment it is no a test I am able to try.

Since is just a graphical/logical binding, I can pick one of the two and create the peering, right?. This is my answer, but I would like to get a confirmation from the community, at least until I cannot try it in a TC I am creating.

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M02@rt37 wrote:

So, if the vpc link where you "bound" the peer goes donwn, the bgp session does not drop, as long as another active member link of the vpc is up! the session rides on that SVI, not the specific path you pikcked in your GUI.

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This is not correct. There two different VPCs, not links of the same vpc. So if the VPC (both links) foes down, the bgp session does not drop, as long as another active member link of the vpc is up! VPC is uop! the session rides on that SVI, not the specific path (VPC) you pikcked in your GUI.

BR,

Irenof

[M02@rt37 · Accepted solution]

Ok, i was focus on one VPC link sorry ....  thanks for that clarification !

The real dependency is on the SVI itself, not on the individual path object we choose when creating the peering.

So you can safely pick one of the two vpc objets when creating the peer, and the session will not drop as long as the SVI remains active on either VPC. The only time it would fail is if the "enitre" SVI goes down (both vpx fail)...

[MHM Cisco World]

I am busy now after two days I can help you if you still want 

Thanks for waiting 

MHM

[irenof]

HI @MHM Cisco World, sorry for my late reply but I have been busy, too. I am still waiting for doing some test in a lab regarding all the stuff wrote in this thread. Did you read all? What do you think?

thanks,

Irenof