Subject: A question regarding section 5.1.1.2 of draft-ietf-l2vpn-signalin g-00.txt

From: Sasha Vainshtein <[email-masked]>
Date: Wed, 10 Sep 2003 10:42:32 +0200

Eric and all,
I have some doubt wrt section 5.1.1.2 "Single Sided Provisioning with
Discovery"
of draft-ietf-l2vpn-signaling-00.txt. The text says that each PE distributes
its list of <vpn-id, local-AII>, while each attachment circuit is
providioned with
the <vpn-id, remote-AII> value.

The case that worries me is like following:
- we have 3 PEs  (PE-1, PE-2 and PE-3)
- PE-1 has a single attachment circuit locally identified as <V, john> and 
  configured to expect <V, fred> as its remote peer
  as the remote side)
- both PE-2 and PE-3 have attachment circuits locally identified as <V,
fred>
  (looks perfectly legal since "fred" is a LOCAL identification) and 
   configured to expect <V, john> as their remote peers.

The draft seems to ignore such a case. In particular, it is not clear to
me what prevents a situation when two unidirectional LSPs -
<PE1, <V, john>, PE2, <V, fred>> and <PE3, <V, fred>, PE1, <V, john>> -
are created.

With best regards,
                                   Sasha Vainshtein
email:     [email-masked]
tel:       +972-3-7659993 (office)
           +972-8-9254948 (res.)
           +972-58-674833 (cell.)

---

From: Eric Rosen <[email-masked]>
Date: Wed, 10 Sep 2003 09:09:30 -0400

Sasha> - both  PE-2 and PE-3 have attachment  circuits locally identified as
Sasha>   <V,  fred>   (looks  perfectly  legal  since  "fred"   is  a  LOCAL
Sasha>   identification) and configured to  expect <V, john> as their remote
Sasha>   peers. 

From the first paragraph of section 5.1.1.2: 

   The  local  name consists  of  a  VPN-id (signaled  as  the  AGI) and  an
   Attachment Individual Identifier which is unique relative to the AGI. 

So the situation in which you have two <V, fred>'s is not allowed.