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

From: Jim Boyle <[email-masked]>
Date: Thu, 26 Jun 2003 11:10:51 -0400 (EDT)

This was written in about an hour, late the night before the deadline
(so show some mercy :)

draft-boyle-tewg-interarea-reqts-00.txt

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.

regards,

Jim

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From: "Ash, Gerald R (Jerry), ALABS" <[email-masked]>
Date: Fri, 27 Jun 2003 18:28:18 -0500

Jim,

> This was written in about an hour, late the night before the 
> deadline (so show some mercy :)

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.  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?

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 :-)

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From: Jean Philippe Vasseur <[email-masked]>
Date: Sat, 28 Jun 2003 02:48:04 -0400

Hi Jerry,

At 06:28 PM 6/27/2003 -0500, Ash, Gerald R (Jerry), ALABS wrote:
>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.

>- what bandwidth specification: Tspec parameters? overbooking 
>considerations?  'reserved bandwidth' as per DSTE?
>"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
>

---

From: "Ash, Gerald R (Jerry), ALABS" <[email-masked]>
Date: Sat, 28 Jun 2003 11:23:11 -0500

JP,

> not correct. Several SPs have multiple ASes and single IGP area/level in 

Certainly not *all* SPs who have multiple AS's also have a single area/level in each (e.g., AT&T).  Further, George Swallow stated in an MPLS WG meeting that many SPs were requesting inter-area TE.  I'm glad that you agree with the need for both inter-area TE and inter-AS TE to be progressed.  

> the question on whether to combine the requirements of inter-area 
> and inter-AS in the same document has been raised on the TEWG list and I 

I also stated on the TEWG list that inter-area and inter-AS TE should be progressed separately, but in parallel.  So if you're associating individuals with SPs, you could also deduce 'AT&T' in the above 'majority' list.  Others agreed that we should progress both in parallel.  

I'm glad that Jim restarted the inter-area TE requirements effort, which you and I and several others first initiated in TEWG a while back.

Jerry

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From: Jean Philippe Vasseur <[email-masked]>
Date: Sun, 29 Jun 2003 12:52:03 -0400

Hi Jerry,

At 11:23 AM 6/28/2003 -0500, Ash, Gerald R (Jerry), ALABS wrote:
>Certainly not *all* SPs who have multiple AS's also have a single 
>area/level in each (e.g., AT&T).

sure this is why I said, "several" ;-) By the way, even if an SP have both, 
this does not mean that they need both inter-area and inter-AS TE ?

>   Further, George Swallow stated in an MPLS WG meeting that many SPs were 
> requesting inter-area TE.  I'm glad that you agree with the need for both 
> inter-area TE and inter-AS TE to be progressed.
>
>I also stated on the TEWG list that inter-area and inter-AS TE should be 
>progressed separately, but in parallel.

So we're in sync !

Fee free to provide your comments on the ET WG req of inter-AS TE.

Thanks.

JP.

>So if you're associating individuals with SPs, you could also deduce 
>'AT&T' in the above 'majority' list.  Others agreed that we should 
>progress both in parallel.
>
>I'm glad that Jim restarted the inter-area TE requirements effort, which 
>you and I and several others first initiated in TEWG a while back.
>
>Jerry