Subject: Using RSVP-TE signaling with ERO for controlling LSP stacking and splicing from the ingress LER

From: "Osama Farrag" <[email-masked]>
Date: Mon, 29 Oct 2001 20:12:05 -0500

I have question/comment regarding the draft RSVP-TE: Extensions to RSVP for
LSP Tunnels "draft-ietf-mpls-rsvp-lsp-tunnel-09.txt"

My question/comment in regarding to sharing resources, splicing and
stacking.

"In CR-LDP, using Explicit route object, the LSPID can be used to identify
the tunnel ingress point as the next hop in the ER. This ER-Hop allows for
stacking new CR-LSPs within an already established CR-LSP. It also allows
for splicing the CR-LSP being established with an existing CR-LSP."

It seems that this capability is missing in RSVP-TE. To be more accurate,
Splicing and stacking may occur but it can't be explicitly controlled by the
ingress LSR using PATH message during establishment of an LSP. Explicit
route control from ingress LER is extermly desired to allow full control on
utilization of network capacity. There are cases where shortest path may not
be the best path.

Currently, In RSVP-TE the receiver determines the "reservation style" of an
LSP; I don't think there is a way for ingress LER to signal a desired
reservation style.

Further more; RSVP-TE does not seem to provide mechanism to allow ingress
LER to leverage A traffic engineered tunnel to steer traffic through it
using ERO.

Is there a means to achieve the same objective using RSVP-TE signaling? if
not, any reasons why the authors choose not to add "Tunnel ID+LSP ID" as a
valid ERO?

Kind Regards
O. Farrag