RE: New I-D on inter-area (and inter-as) MPLS TE requirements

[Jean Philippe Vasseur <jvasseur@cisco.com>]

Hi Jerry,

At 06:28 PM 6/27/2003 -0500, Ash, Gerald R (Jerry), ALABS wrote:
> Jim,
>
> > This was written in about an hour, late the night before the
> > deadline (so show some mercy :)
> > draft-boyle-tewg-interarea-reqts-00.txt
>
> It's pretty good for an hour's worth :-)
>
> > The goal was to make sure that we cover requirements for
> > inter-area TE.  To show that it's not that hard to couple in
> > the requirements for inter-as TE, I extended it to cover that
> > as well.
>
> General comments:
> I'm glad you're providing inter-area TE requirements.  I agree that both 
> inter-area TE and inter-AS TE should be progressed together, and would not 
> favor progressing inter-AS TE without also progressing inter-area TE.  It 
> would seem if a SP needed inter-AS TE, they would usually also need 
> inter-area TE.
Well no. I'm of course not against the idea of working on inter-area TE 
reqs but stating that the SPs that need Inter-AS TE also need inter-area is 
not correct. Several SPs have multiple ASes and single IGP area/level in 
each AS.

As I said during the last CCAMP meeting, although some mechanisms might 
work for both (see draft-ieft-mpls-nodeid-subobject-01.txt, 
draft-vasseur-mpls-loose-pah-reopt-02.txt, 
draft-ayyangar-inter-region-te-00.txt,...), the requirements are quite 
different. For instance, if you take a look at the TE WG Inter-AS TE 
requirement draft (draft-ietf-tewg-mpls-te-req.00.txt), you'll see that 
quite a few requirements are specific to inter-AS TE:
        - Policy control,
        - Confidentiality,
        - Some management functions,
        - ....

Moreover, the question on whether to combine the requirements of inter-area 
and inter-AS in the same document has been raised on the TW WG list and I 
think that there was a majority stating that there should be separate 
documents (NTT-C, EQUANT, FRANCE TELECOM, INFONET, SBC, ...).

> A while back vendors claimed that many SPs were requesting inter-area 
> TE.  I assume that's still the case, else can someone explain why SPs 
> would want inter-AS TE and not inter-area TE?
As stated before, many SPs have multiple ASes but single IGP area/level.

Of course your comments on draft-ietf-tewg-mpls-te-req.00.txt are very welcome.

JP.

> Specific comments:
> 1. Some of the functionality's in Section 1.1 should be more specific, e.g.,
> - what bandwidth specification: Tspec parameters? overbooking 
> considerations?  'reserved bandwidth' as per DSTE?
> - what priorities: setup priority? holding priority? preemption priority 
> as per DSTE?
> 2. Section 3.1:
> "when the source is more than one area away from the destination, the 
> destination's border router may send back a Path Error.  Ideally, the 
> source's border router would try another border router into the 
> destination's area, however with current protocol, the Path Error will 
> propagate to the source."
> sounds like a requirement for [crankback] functionality 
> http://www.ietf.org/internet-drafts/draft-iwata-mpls-crankback-06.txt
> 3. Section 3.4:
> " Diffserv TE should be directly translatable at border-routers, as the 
> class-type of an LSP is explicit for class-types greater than 0 and 
> not-existent in the path message for class-type 0."
> Are you proposing to standardize class-type 0 to mean best 
> effort?  Section 1.4 also refers to 'conventions' for class-types 0, 1, and 2.
>
> Regards,
> Jerry
>
> ~ an hour's worth of commenting :-)