Re: Poll to adopt draft-rosen-l3vpn-mvpn-bidir-03 as a L3VPN WG document

[Yakov Rekhter <[e-mail]>]

Ben,

> Colleagues,
>  
> This e-mail is to start a poll on whether the L3VPN WG should adopt 
> draft-rosen-l3vpn-mvpn-bidir-03.txt as a L3VPN WG document.
>  
> Please indicate your support or otherwise by responding to this message (with
> yes/support or no/do not support) or e-mailing the WG chairs privately.
> 
> If you do not support the adoption of the document it would be useful if you 
> could also state the reason for your objection.
>  
> Please send your responses by midnight August 15th May PDT.
> 
> FYI Eric has outlined his view on the need for this document on the 
> mailing list previously which you can read here:
> http://www.ietf.org/mail-archive/web/l3vpn/current/msg02901.html

It is premature to discuss adoption of draft-rosen-l3vpn-mvpn-bidir-03.txt 
as a L3VPN WG document, and here is why.

There was already a discussion in L3VPN WG about adopting
draft-rosen-l3vpn-mvpn-bidir as an L3VPN WG document. From your
e-mail on 10/29/2010:

   To follow-up on this, from comments on the mailing list and private
   conversations between the chairs and some participants it would
   appear that for BiDir P-tunnels at least:
   
   - There is interest in the work and some loose agreement among the
   people that we spoke with that the existing specifications only
   minimally specify solutions using BiDir P-tunnels
   
   - But that there are some quite different views on what the scope
   of any work on BiDir P-tunnels should be.
   
   We already have draft-rosen-l3vpn-mvpn-bidir on the table which has
   received some debate. It would be useful if one or more of the
   people that are not happy with the scope of draft-rosen-l3vpn-mvpn-bidir
   were to make alternative proposal(s) for the scope of work required
   to address BiDir P-tunnels so we can see where the common ground
   may be as a start to see if we can progress a specification for
   BiDir P-tunnels.

In response to your request to put an alternative proposal for
the scope of the work required to address Bidir P-tunnels,
I proposed the following (in my e-mail on 11/22/2010):

   The scope of work in support of mp2mp P-tunnels should be guided by
   draft-ietf-l3vpn-mvpn-considerations.
   
   From draft-ietf-l3vpn-mvpn-considerations:
   
      The use of MP2MP P-tunnels may provide
      some scaling benefits to the service provider as only a single MP2MP
      P-tunnel need be deployed per VPN, thus reducing by an order of
      magnitude the amount of multicast state that needs to be maintained
      by P routers. 
   
   Therefore, the scope of work should be limited to the cases where
   mp2mp P-tunnels do provide scaling benefits in conjunction with
   the C-multicast routing schemes defined in [MVPN]. Specifically, the
   scope of work should be limited to (1) use of mp2mp P-tunnels for
   I-PMSI, and (2) support of C-bidir with the "Partitioned Sets of
   PEs" method using a partial mesh of mp2mp P-tunnels (as discussed in 
   section 11.2.3 of [MVPN]). 
   
   From draft-ietf-l3vpn-mvpn-considerations:
   
      5.  Avoiding duplicates
   
      It is recommended that implementations support the procedures
      described in section 9.1.1 of [I-D.ietf-l3vpn-2547bis-mcast]
      "Discarding Packets from Wrong PE", allowing fully avoiding
      duplicates.
   
   Therefore, use of mp2mp P-tunnels for I-PMSI must fully specify
   procedures to support 9.1.1 of [MVPN].
   
   New work must not change/modify the existing procedures specified
   in [MVPN] and [BGP-MVPN]. New work must not introduce new mechanisms
   and/or procedures unless it shows that the mechanisms/procedures
   specified in [MVPN] and [BGP-MVPN] are insufficient for the purpose
   of delivering what is within the scope (as described above).

There was some subsequent e-mails on the list, but the L3VPN WG
never reached a consensus on the scope of this work.

Therefore, before discussing adopting of draft-rosen-l3vpn-mvpn-bidir as 
an L3VPN WG document, the L3VPN WG must first reach a consensus
on the scope of the work related to the use of Bidir P-tunnels.

Yakov.