Re: Comments on draft-rabadan-l2vpn-evpn-optimized-ir-00

["Rabadan, Jorge (Jorge)" <[e-mail]>]

Robin,

The scope of the current version of the optimized-ir draft is EVPN and ingress replication for layer-2 BUM traffic. So I won’t comment on the l3vpn draft for the moment.
As for draft-zhang-l2vpn-evpn-selective-mcast-01, I understand it tries to add selective multicast trees to EVPN, which I agree is something that was missing compared to RFC7117 for VPLS.

Selective multicast trees optimize the transport of specific IP multicast streams, setting up a different tree (type p2mp, IR, etc) to only those nodes interested in those IP multicast streams.
The optimized-ir draft addresses different issues. It actually modifies the IR tunnel type for inclusive multicast trees (BUM traffic). Because in reality we are just creating a different version of an IR tunnel:

  *   We still use the inclusive multicast route (because it will still tell the ingress PE where to send the BUM traffic)
  *   We add a new tunnel type (because it is no longer IR) and new flags in the reserved bits of the PMSI tunnel attribute.

This new tunnel type (AR) and the AR-type field can actually be used in draft-zhang-l2vpn-evpn-selective-mcast-01 for selective multicast trees if we needed to do the same optimization for selective multicast trees that use IR.

I hope that explains better why we are not using a separate route-type for this.
As for the compatibility, the solution is completely backwards compatible with the existing EVPN implementation, and it does not clash with MVPN or VPLS-MCAST as described in the draft:

  *   we are defining a new tunnel type, which should be discarded by PEs not supporting the draft
  *   we are defining some flags, which are not clashing with the “L” flag defined in RFC6514, that you also use in the selective mcast tree draft

I hope this helps clarifying the draft.
Thank you.
Jorge


From: Lizhenbin <[e-mail]<mailto:[e-mail]>>
Date: Wednesday, July 23, 2014 at 10:09 AM
To: "[e-mail]<mailto:[e-mail]>" <[e-mail]<mailto:[e-mail]>>
Subject: Comments on draft-rabadan-l2vpn-evpn-optimized-ir-00


Hi authors,

To follow up on my comments in the l2vpn meeting, following two drafts proposed in L2VPN WG and L3VPN WG are for your reference:

-- draft-li-l3vpn-mvpn-role-state-ad-02
-- draft-zhang-l2vpn-evpn-selective-mcast-01
The role information is truly a possible way to help optimize the BUM traffic in EVPN. Regarding the possible solutions, I have following more comments:

-- It is better to work out a generic role-info advertisement solutions based on all possible application scenarios.

-- Taking into account compatibility, it is better to define a new route type for NLRI or a new attribute to advertis the role information. The extension of PMSI Tunnel attribute may proposes compatibility issue for BGP-based MVPN defined in RFC 6514.





Regards,

Zhenbin(Robin)