Subject: changes in draft-ietf-l2vpn-signaling-07.txt

From: Yakov Rekhter <[email-masked]>
Date: Wed, 08 Mar 2006 07:10:07 -0800

Folks,

>From 3.2.2.1:

   It is RECOMMENDED that a single VPN-ID be assigned to a VPLS
   instance.  That VPN-ID MAY be a VPN-ID as defined in [RFC2685], in
   which case it SHOULD be encoded as an RD by placing the value 0x80 in
   the first byte of the RD (to indicate the RD type) and the 7-byte
   VPN-ID in the remaining bytes of the RD.

The above is clearly well beyond an editorial change. It was added
after the document passed the WG Last Call. It was added with no
discussion on the l2vpn mailing list, and no consensus of the WG.

With this in mind before progressing this document any further
I'd like the authors of draft-ietf-l2vpn-signaling-07.txt to document 
the rationale for this change, and for the WG chairs to ask for the 
WG consensus on this change.

Yakov.

---

From: Bruce Davie <[email-masked]>
Date: Wed, 8 Mar 2006 12:29:16 -0500

Yakov,
  Fair comment. As you know we did discuss this privately but reached  
no consensus. So I have no problem discussing it on the list.

Let me explain the change. First,  there is an editorial change to  
remove a dependency of draft-ietf-l3vpn-bgpvpn-auto-06.txt. That is  
why I said:

> That VPN-ID MAY be a VPN-ID as defined in [RFC2685], in

where as previously there was text that said

If the globally unique identifier for a VPLS is
    an RFC2685 VPN-id, it can be encoded as an RD as specified in [BGP-
    AUTO].

The non-editorial change is the first sentence:

>    instance.

whereas previously the draft said:

    In order to use BGP-based auto-discovery as specified in [BGP-AUTO],
    there must be at least one globally unique identifier associated  
with
    a VPLS, and each such identifier must be encodable as an 8-byte  
Route
    Distinguisher (RD).

That is, in addition to requiring that there MUST be *at least one*  
globally unique ID for a VPLS, it now says, in effect, that there  
SHOULD be exactly one.

The rationale for the change was that, on close reading of the PWE  
control protocol draft, I realised that some implementations of that  
draft might attempt to build 2 PWs between a pair of VSIs if the two  
VSIs had different RDs. Rather than try to change the PWE draft  
(which was already in the RFC editor queue) I elected to add this  
guidance - but not a MUST - to the l2vpn signaling draft.

Since the draft still allows the use of multiple RDs per VPLS  
instance, I leave it to the WG to decide if the change is acceptable  
or not.

Bruce

---

From: Bruce Davie <[email-masked]>
Date: Wed, 8 Mar 2006 11:48:04 -0500

Yakov,

Bruce