Subject: Regarding draft-ash-multi-area-te-reqmts-01.txt

From: "Manral, Vishwas" <[email-masked]>
Date: Wed, 5 Dec 2001 02:47:47 -0500

Jerry/others,

1. I guess you have not taken into consideration the draft 
http://www.ietf.org/internet-drafts/draft-srisuresh-ospf-te-01.txt

This draft does figure on the TE page too, and there has been discussion on
the draft especially on the OSPF list. This uses an approach of summary LSA
for TE, infact it has defined new TE LSA's corresponding to an LSA in OSPF.

2. The requirements for multi-area TE talk about 
a) maximize network utilization and minimize cost, considering QoS
objectives
b) minimize routing overhead (includes LSAs, crankbacks, queries, etc.),
i.e., maximize scalability
 The requirements are related. The requirements should be to maximize
network utilization even while sending minimum routing overhead. (Try and
convey as much even without sending too much information)

3. Here are some general requirements like point a) and b) could be:-

  a) Promptness could be another requirement. To adapt to multi-area
topological changes quickly i mean.
  b) It should be extensible.(for example the new TE method as in point 1.
is not extensible as are methods that use specific formats(particular LSA's)
while TLV methods are extensible)
  c) Also minimum routing overhead in case of change(for instance the TLV's
as defined in OSPF, force the entire contents of the LSA to be resent if
only a part of the LSA is modified.)
  d) Also compatibility with intra area TE mechanisms.

4. Section 3 talks about LSA's/ABR's. Also else where there are talks of
LSA's. It should be specified that most of the text relates to OSPF, as in
ISIS we do not have LSA's, but LSPDU's.

Thanks,
Vishwas

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From: "Ash, Gerald R (Jerry), ALCTA" <[email-masked]>
Date: Sun, 9 Dec 2001 10:31:07 -0500

Vishwas,

Thanks for your email, see responses below.

Thanks,
Jerry

>for TE, infact it has defined new TE LSA's corresponding to an LSA in OSPF.

Yes, it should be mentioned.  There are other summary LSA mechanisms mentioned, e.g., http://search.ietf.org/internet-drafts/draft-venkatachalam-ospf-traffic-02.txt, however the I-D is intended to be inclusive.

>convey as much even without sending too much information)

Agreed.

>  a) Promptness could be another requirement. To adapt to topological
>changes quickly i mean.

All sensible requirements.  The task if this work moves forward is to include the minimal set of essential, agreed-to requirements.

>LSA's. It should be specified that most of the text relates to OSPF, as ISIS
>we do not have LSA's, but LSPDU's.

Yes, we are using OSPF terminology and this should be clarified.