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Vinay,
See
also my draft, draft-hummel-mpls-hierarchical-lsp-00.txt:
An
hierarchical LSP (H-LSP) shall concatenate normal LSPs (and/or hierarchical LSPs
of lower hierarchical level) just like an normal LSP
concatenates
physical links. However, it takes some changes in CR-LDP signalling as to establish
hierarchical LSPs:
Explicit Routing: the ingress of the H-LSP provides the
complete sequence of sub H-LSPs to be concatenated (= change in
ER-TLV).
Implicit Routing: the ingress (the transit)
node of the H-LSP needs to send the LSP-ID of the first (the
next) sub H-LSP to be concatenated (=new TLV).
The messages (LABEL-REQUEST, LABEL-MAPPING,...) have to
be sent THRU "Control-Plane" sub H-LSPs (like thru tunnels) whose endpoints
comply with the
endpoints of the to be concatenated "User Plane" sub
H-LSPs.
The LSP-IDs of the
involved "Control-Plane" sub H-LSPs should be derivable from the LSP-IDs of the
involved "User-Plane" sub H-LSPs.
I stressed that, based
on a small but contiguous partial mesh of LSPs an effective full mesh can be
accomplished by building H-LSPs.
The N-square problem
would completely disappear. Costs, i.e. work for the H-LSPs would only happen at
the rim of the network. Indeed the network would
not
even know that the
H-LSPs exist, as all messages are tunnelled thru the "Control Plane" sub
H-LSPs.
I would appreciate if
more people supported this work on
H-LSPs.
Heinrich
Hummel
Siemens
-----Ursprüngliche
Nachricht-----
Von: Vinay Vernekar [mailto:vinay.vernekar@wipro.com] Gesendet: Dienstag, 16. April 2002 15:18 An: ccamp@ops.ietf.org; gmpls-ops@mplsrc.com Betreff: Need for hierarchical SONET/SDH LSPs.
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