Technical Summary
Seamless MPLS design enables a single IP/MPLS network to scale over
core, metro and access parts of a large packet network infrastructure
using standardized IP/MPLS protocols. One of the key goals of
Seamless MPLS is to meet requirements specific to access, including
high number of devices, their position in network topology and their
compute and memory constraints that limit the amount of state access
devices can hold.This can be achieved with LDP Downstream-on-Demand
(LDP DoD) label advertisement. This document describes LDP DoD use
cases and lists required LDP DoD procedures in the context of
Seamless MPLS design.
In addition, a new optional TLV type in the LDP Label Request message
is defined for fast-up convergence.
Working Group Summary
There is a strong support for this document in the working group
and it has been has been well reviewed.
Draft has been mainly driven and architected by an operator that
have specifed the Seamless MPLS, based on opreational experiences.
Document Quality
There are both existing and intended implementations of this
specification.
The document has been reviewed as needed, the working
group last call was brought to the attention of SG15 in
ITU-T.
Personnel
Loa Andersson is the document shepherd.
Adrian Farrel is the responsible AD.
RFC Editor Note
Please replace "ISIS" with "IS-IS" throughout.
On first use, please expand RIB and FIB as
Routing Information Base
Forwarding Information base
Please expand ECMP as Equal-Cost Multipath
Please expand LAG as Link Aggregation Group
Please expand FEC as Forwarding Equivalence Class
Please expand IPFRR as IP Fast-reroute
Please expand LFA as Loop-Free Alternate
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Abstract s/specific to access/specific to access networks/
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Section 1 s/(access ABRs)/ABRs/
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Section 3.1.1...
In order to facilitate ECMP and IPFRR LFA local-repair, the upstream
AN/AGN1x also sends LDP DoD label requests to alternate next-hops per
its RIB, and install received labels as alternate entries in its LIB
and LFIB.
As well as expanding the acronyms as requested above, please...
s/local-repair/ local-repair [RFC5714]/
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Section 4.3.2 s/algoritm/algorithm/
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Section 4.6
To support local-repair with ECMP and IPFRR LFA, access LSR/ABR
requests labels on both the best next-hop and the alternate next-hop
LDP DoD sessions, as specified in the Label Request procedures in
Section 4.3. If remote LFA is enabled, access LSR/ABR needs a label
from its alternate next-hop toward the PQ node and needs a label from
the remote PQ node toward its FEC/destination. If access LSR/ABR
doesn't already know those labels, it requests them.
Note that "PQ" has no expansion!
s/destination./destination [I-D.ietf-rtgwg-remote-lfa]./
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Section 9.2 please add
[I-D.ietf-rtgwg-remote-lfa]
Bryant, S., Filsfils, C., Previdi, S., Shand, M. and N.
So, "Remote LFA FRR", draft-ietf-rtgwg-remote-lfa, (work
in progress.
[RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework", RFC
5714, January 2010.