VXLAN EVPN with eBGP as Underlay

[j.a.m.e.s]

Dear All,

I am reading "Building Data Centres with VXLAN BGP EVPN" in preparation for a datacentre refresh project.

For internal reasons, our underlay routing protocol is eBGP. In the book (page 108) it recommends that the EVPN peering is done loopback to loopback with eBGP multihop, presumably to help avoid confusion with the underlay peerings. 

Q1:

Could anyone with any experience of this tell me if this means peering between the Spine Loopback and the NVE loopback on the leafs? Or should there be a separate loopback on the leafs to use for EVPN peering purposes?

Q2:

Every example I see of EVPN fabrics places the VXLAN vlans in vrfs, while loopbacks (including the NVE loopback) and p2p links are in the default vrf. Is it absolutely necessary to use different VRFs (I don't have any multitenancy requirements)?

Thank you for your assistance.

Regards

James.

[alfredobosca]

Hello,

eBGP commonly peers using the physical interface as there is generally only one path between the two eBGP peers. Loopback interface are used into iBGP.

Best regards,

[Vinit Jain · Accepted solution]

HI James

To your question regarding using VRF, you will have to use VRF for defining a Tenant. You will need atleast one tenant for your vxlan evpn deployment. Multiple VRF's are required only for multi-tenancy purposes.

To your first question, you can have BGP peering on the same loopback which is also acting as the NVE source interface or you can use a different loopback interface as well.

Hope this helps.