Hi,

I think you should check out 
https://tools.ietf.org/html/draft-ietf-bess-evpn-df-election-framework-09

This draft updates RFC7432 in certain aspects of the DF Election, and it is 
already at the RFC editor.

Check out the use of Ethernet Tag in the document.

   o Ethernet Tag - used to represent a Broadcast Domain that is
     configured on a given ES for the purpose of DF election. Note that
     any of the following may be used to represent a Broadcast Domain:
     VIDs (including Q-in-Q tags), configured IDs, VNI (VXLAN Network
     Identifiers), normalized VID, I-SIDs (Service Instance
     Identifiers), etc., as long as the representation of the broadcast
     domains is configured consistently across the multi-homed PEs
     attached to that ES. The Ethernet Tag value MUST be different from
     zero.

Thanks.
Jorge

From: BESS <bess-boun...@ietf.org> on behalf of Jaikumar Somasundaram 
<jaikumar.somasunda...@ericsson.com>
Date: Friday, April 5, 2019 at 6:15 AM
To: "bess@ietf.org" <bess@ietf.org>
Cc: P Muthu Arul Mozhi <p.muthu.arul.mo...@ericsson.com>
Subject: [bess] DF election rule in EVPN MH, for untagged interface - reg

Hi All,

RFC7432, section 8.5, talks about DF election algorithm (service carving 
algorithm)

only for <ES, VLAN> for VLAN-based service or <ES, VLAN bundle> for VLAN-(aware)
bundle service.

But there wont be any vlan id for untagged interface and so I wonder
how the service carving algorithm can be applied to elect the DF.
Also, should I use the lower VLAN ID even in the case of VLAN-bundle
service, for electing the DF?

Could some one help me to understand this please?

==========<snip from RFC 7432, section 8.5>===============
8.5<https://tools.ietf.org/html/rfc7432#section-8.5>.  Designated Forwarder 
Election

…

   The default procedure for DF election at the granularity of <ES,

   VLAN> for VLAN-based service or <ES, VLAN bundle> for VLAN-(aware)

   bundle service is referred to as "service carving".
…

      Assuming a redundancy group of N PE nodes, for VLAN-based service,

      the PE with ordinal i is the DF for an <ES, VLAN V> when (V mod N)

      = i.  In the case of VLAN-(aware) bundle service, then the

      numerically lowest VLAN value in that bundle on that ES MUST be

      used in the modulo function.
…
=========<snip end>======================================

Thanks & Regards
Jaikumar S

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