Inter-sr iBGP for EVPN routes are not working

Products

• VMware NSX

Issue/Introduction

Inter-SR iBGP session between the Edge nodes gets established but EVPN BGP learned routes are not exchanged between them

Environment

4.2.2.1

Cause

The cause of the issue is expected as the routes that are learned prior to enabling inter-SR on a T0-VRF are properly exchanged between Edge nodes but Incremental updates/withdraw post enabling inter-SR on a T0-VRF doesn't work. These routes are added/deleted from the T0-VRF on the local Edge node, but not sent over the iBGP sessions.

 

Resolution

Inter-SR will work with pure IPv4/IPv6 routes learned via static/connected/redistributed from other IGP protocol and BGP learned through IPv4/IPv6 unicast. The routes learned via EVPN address family is not supported.

Inter-SR and EVPN are incompatible features. This is applicable to both the single-site and multi-site topologies.

 

Additional Information

Also Multi-VRF Inter SR flag once enabled can't be disabled. In-order to cleanup the inter-SR routes, disable the inter-SR on individual T0-VRF.

The incompatible feature between EVPN with inter-SR will be explicitly mentioned in next NSXT release document as per Eng comments 

The feature of "Multi-VRF Inter SR" can't be disabled once it is enabled. will also be mentioned in next NSXT release document