Hi Mankamana,

I am going to skip the broadcast domain terminology part and focus on the rest 
of the questions.

Please see zzh> below.


https://datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-vpws-fxc-08<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/html/draft-ietf-bess-evpn-vpws-fxc-08__;!!NEt6yMaO-gk!FFtUshclX4bBjBBkKoSyZzp3SP7trOYtPbvL98kBiCuq9fBdYc8AwHCRqqZBX9PB0dStV9mJtg07Vr6e$>
 says:

   [RFC8214] describes a solution to deliver P2P services using BGP
   constructs defined in [RFC7432].  It delivers this P2P service
   between a pair of Attachment Circuits (ACs), where an AC can
   designate on a PE, a port, a VLAN on a port, or a group of VLANs on a
   port.

It seems that:

- Each pair of AC in vpws-fxc is given a normalized VID as the AC ID.
- In this draft, each VLAN across the MHES is given an ACID and signaled in the 
attachment circuit ID Extended Community (ACID EC)
I do not think this draft is associated directly with
draft-ietf-bess-evpn-vpws-fxc

zzh> I referred to the vpws-fxc draft because this draft has the following text:

   The attachment circuit ID plays the role of normalized VID.  It is
   defined as per [I-D.ietf-bess-evpn-vpws-fxc].

Zzh> I'll put that behind as well. I probably included that to help myself 
understand the AC ID.


I am confused as to why this draft applies only to MHES. Let's say there is no 
MH and the CE is only homed to PE1, but both PE1 and PE2 host subnet S1. When 
PE2 gets a packet destined to H1 and it is to be routed down PE2's IRB (and 
then switched to PE1 - asymmetric mode), what VLAN ID should PE2 use? I suppose 
what is needed is a mapping between vlan and subnet - something to be 
configured locally. But once that is done, the MHES problem is also solved, 
right? And the vlan/subnet mapping is comparable to the ACID configuration.
Because remote side does not need to know about which access interface MAC was 
learnt. Only MH peer needs to know about which port it has to send out on.
Zzh> The problem is with the L3 traffic that is routed down the remote PE2's 
IRB interface in the asymmetric mode. It does not have an incoming VID since it 
is not L2 traffic, and PE2 needs that in the encapsulated Ether header. That is 
the same problem as originated stated in the draft - when a multihoming PE 
needs to route L3 traffic down the IRB interface.
Zzh> Jeffrey

In the case of syncing IGMP/MLD state across MHES PEs, we just need to attach 
the VLAN info to the routes.


Finally, even if we want to go with the solution in the draft, I don't think we 
should call this the 4th service interface. It is just about how to do single 
IRB on the vlan bundle service interface. Adding the 4th service interface just 
adds confusion.
Naming we can discuss and conclude.


Thanks.

Jeffrey

Juniper Business Use Only




Juniper Business Use Only
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