Subject: [bess] draft-mohanty-bess-evpn-bum-opt-00 - clarification on problem description

From: Sandy Breeze <[email-masked]>
Date: Wed, 21 Mar 2018 15:57:38 +0000

After some discussion, we acknowledge the problem description needs further clarification for this not to become too specific a use case.  Consider the following example of our existing live deployments;

The main points to articulate here are;

  *   PE[1..4] are at the boundary of an EVPN/MPLS domain (core side) and an EVPN/VXLAN domain (datacentre fabric side)
  *   They are responsible for L2VNI VTEP from ToR and MPLS L2VPN in core.
  *   From their point of view, 1 BD = 1 L2VNI (=1 ES).
  *   For any given DF type (modulo/HRW/etc) they distribute DF’s per-ES between them.
  *   Therefore, all nDF PE’s attract BUM for ES’s they’re not allowed to forward on and hence the waste of bandwidth in the EVPN core and cycles.

In our case, the solution we propose works very well.  We also showed this does no harm for the more typical EVPN-multihoming at the PE use case yesterday, which held up to technical scrutiny.

Sandy