Hi,
IMHO the two drafts are not so closely related.
Hierarchy bis describes how, when an LSP is set up, the ingress may
indicate to the egress that the LSP is to be advertised or used as a
link in some specific network layer.
LSPs set up for VCAT are not used in that way. They are grouped
together and the whole group is used as a link in another network layer.
So, for VCAT, one might use the call as the mechanism to exchange
information about how to use the entire VCG as a link in the client
layer. Alternatively (if one is implementing strictly according to the
architecture) one might have three layers to consider...
- The server layer where a call coordinates multiple TDM LSPs
- The VCAT layer where a single hop LSP is requested between
VCG end points resulting in the server layer call. The VCAT
layer LSP would use hierarchy bis to determine that it should
be advertised as a TE link in the client layer.
- The client layer where a magic TE link appears as the result of
the VCAT layer LSP.
Depending on the deployment, the use of a VCAT layer LSP might be
considered to be over-engineering. Just because an architecture
defines multiple layers, it does not mean you have to implement them
explicitly. It might be enough for the server layer call to provide
the coordination with the client layer direct.
Cheers,
Adrian
----- Original Message ----- From: "Bardalai, Snigdho"
<Snigdho.Bardalai@us.fujitsu.com>
To: "Kohei Shiomoto (E-mail)" <shiomoto.kohei@lab.ntt.co.jp>; "Greg
Bernstein (E-mail)" <gregb@grotto-networking.com>
Cc: "Ccamp (E-mail)" <ccamp@ops.ietf.org>; "Adrian Farrel (E-mail)"
<adrian@olddog.co.uk>
Sent: Saturday, March 15, 2008 7:25 PM
Subject: Signaling client layer LSP over VCAT server layer LSP
Hello Kohei and Greg,
I have a question about client layer LSP signaling (e.g. ethernet)
over VCAT server layer resources.
From reading 'draft-ietf-ccamp-lsp-hierarchy-bis-03.txt' it is not
clear how
will this exactly work.
For example, we set up a VCAT group (i.e. by signaling multiple STS1
LSPs) as allowed by the VCAT ID. I believe each of these LSPs would
appear as LSP_TUNNEL_INTERFACEs in the client layer with bandwidth
capacity equivalent to STS1 (i.e. 52mbps). My question is which
LSP_TUNNEL_INTERFACE will be used for signaling the ethernet LSP, I
think an additional component link with bandwidth capacity equivalent
to the aggregate bandwidth will have to be created.
Is there a defined way of handling this situation?
Thanks,
Snigdho