Subject: unnumbered links/control channel separation in GMPLS signaling

From: Hang Liu <[email-masked]>
Date: Mon, 6 Aug 2001 11:00:43 -0400

Hi. Bala and Kireeti,

By going over the new gmpls drafts and other two related drafts about
unnumbered links and link bundles, draft-kompella-mpls-bundle-05.txt and
draft-ietf-mpls-rsvp-unnum-01.txt, I have several questions and hope you can
help me to clarify them.

(1)	In draft-ietf-mpls-generalized-rsvp-te-04.txt, section 8.1 defines
IF_ID RSVP_HOP object that includes IF_ID TLV. It does not mention how to
include IF_ID TLV in the ERO. Can I assume that IF_ID TLV can be put into
ERO to replace normal explicit node/interface ID by the ingress node? The
receiving node checks the initial subobject in the ERO to determine the
outgoing link. If the receiving node is an intermediate node, it should copy
the IF_ID TLV from the initial ERO subobject to the new IF_ID RSVP_HOP. This
new IF_ID RSVP_HOP will be contained in the outgoing Path message to the
next hop. Note that the initial subobject is removed from the ERO before the
Path message is sent to next hop. 
(2)	For unnumbered bundled links, the IF_ID in the ERO should be the
IF_ID of this bundled link. If the bi-directional LSP is requested, both
upstream IF_ID and downstream IF_ID will be included in ERO. Upstream IF_ID
and downstream IF_ID may not be one-to-one mapping. However only one IF_ID
TLV (IF_INDEX) is defined in section 9.1.1,
draft-ietf-mpls-generalized-signaling-05.txt. Do we need to define a
separate downstream IF_ID TLV and an upstream IF_ID TLV? This applies to the
case of any unnumbered links/link bundles without upstream and downstream
one-to-one mapping.

Thank you very much.

Hang Liu
Tellium, Inc