Re: Progressing the three inter-domain I-Ds

[Dimitri.Papadimitriou@alcatel-lucent.be]

hi adrian

o) a couple of generic comments on the third doc

- the doc. states applicability to GMPLS but sometimes only ref. MPLS-TE
signaling further on e.g. section 3.1

" - The inter-domain TE LSPs are signaled using RSVP-TE ([RFC3209])."

and many others in section 4.

- the are many comparison with PCE technique along the doc. - well that's 
fine but outside the scope of the document except if the purpose is to 
indicate how different techniques can be combined together and which 
interop issues may result from it

o) a couple of specific comments 

end of section 2: 

section 3.1: "* The complete list of boundary LSRs along the path"
-> list of domain identifier e.g. AS numbers also applies here ?

last § of section 3.1 is the most important one, signaling protocol are
independent of the routing topology itself, i.e. not because a node is
an ABR or an ASBR that comp. occurs but simply because he has no path 
to reach the next (loose) hop - an intermediate node should still maintain
capacity to perform such operation

section 3.3 "The path computation
   technique described in this document applies to the case of a single
   AS made of multiple IGP areas, multiples ASs made of a single IGP
   areas or any combination of the above.  For the sake of simplicity,
   each routing domain will be considered as single area in this
   document. "

-> not sure to understand the reasoning, at the end these examples must
remain illustrative and not restrict applicability - all these tutorial
like material should better go in an appendix -

section 3.1 "In any case,
   no topology or resource information needs to be distributed between
   domains (as mandated per [RFC4105] and [RFC4216]), which is critical
   to preserve IGP/BGP scalability and confidentiality in the case of TE
   LSPs spanning multiple routing domains."

then Section 4
"In terms of computation of an inter-AS TE LSP path, an interesting
   optimization technique consists of allowing the ASBRs to flood the TE
   information related to the inter-ASBR link(s) although no IGP TE is
   enabled over those links (and so there is no IGP adjacency over the
   inter-ASBR links).  ...
"Thanks to such an optimization, the inter-ASBRs TE link information
   corresponding to the links originated by the ASBR is made available
   in the TED of other LSRs in the same domain that the ASBR belongs to."

but after
"Note that no topology
   information is flooded and these links are not used in IGP SPF
   computations.  Only the TE information for the outgoing links
   directly connected to the ASBR is advertised."

-> can one of the author clarify 1) is flooding involved or not ?
2) what get's flooded and under which conditions 3) what is the 
scope of the flooding 4) how this mechanism positions against the
requirements of 4105 and 4216


o) a couple of edits
 
section 1:

ABR Router, ASBR Router - redundant R

the most important def. is the "domain" def. which can be found in the
frm doc but not recorded here this would clarify sentence like

"The mechanisms proposed in this document are also applicable to MPLS
 TE domains other than IGP areas and ASs."

ref. H-LSP and S-LSP with the appropriate docs

state that inter-domain recovery is going to be addressed in a set of
specific docs

hope this will help,
- d.




"Adrian Farrel" <adrian@olddog.co.uk>
Sent by: owner-ccamp@ops.ietf.org
09/01/2007 23:13
Please respond to "Adrian Farrel"
 
        To:     <ccamp@ops.ietf.org>
        cc: 
        Subject:        Progressing the three inter-domain I-Ds


Hi,

We now have updated versions of the three inter-domain signaling I-Ds:

- draft-ietf-ccamp-inter-domain-rsvp-te-04.txt
- draft-ietf-ccamp-lsp-stitching-04.txt
- draft-ietf-ccamp-inter-domain-pd-path-comp-03.txt

Our plan is:
1. WG chairs do detailed review over the next couple of weeks
2. Editors apply necessary updates
3. We hold a WG last call for the three I-Ds together

If you are interested in this work, I suggest that now might be a good 
time 
to remind yourself about the I-Ds, have a good read, and see if you can 
get 
any substantial comments in to coincide with the WG chairs' review.

Thanks,
Adrian