RE: Differentiated Routing, not only plain rambo-SPF

From: Ayyasamy, Senthilkumar (UMKC-Student) (saq66@umkc.edu)
Date: Mon Aug 05 2002 - 20:36:15 EDT


> I am also talking about DiffServ-aware-MPLS-TE.
> In the draft-ietf-tewg-diff-te-reqts-05.txt authors
> clearly mentioned about problem statement and how we
> can benefit from DiffServ-aware-MPLS-TE (even if there
> are some scalability issues). Effectively, authors
> are trying to solve SOME problem - then how can
> you can say that DiffServ-aware-MPLS-TE (aka DiffRouting)
> is not going to solve ANY problem.
Diffserv aware MPLS TE draft doesn't call for bar on SPF. But
you people are keeping that as a subject and discussing.

Some of the definitions and road examples of diffrout doesn't fit
the bill of diffserv aware MPLS TE.

As of now, whatever techniques standardized by TE-WG, is applicable
only for intra-domain (including diffserv-aware TE.) But read some
of your mails, you talk about end to end issues.

Do you get your problem now? If you are not clear with your problem
statement, you will tent to make deviating observations.

If Diffserv-aware-MPLS-TE = diffrout, I am in full agreement with some
of your views. But remember again, you made some comments about end to end
delay issues which even Faucheur et all won't accept.

Hummel, was your original proposal same like Diffserv-aware-TE. I thought
it was different.

>
> Scalability issues in TOS Routing are different
> from scalability issues in DiffRouting (if you consider
> TOS routing is applicable in traditional hop-by-hop
> routing case and DiffRouting is applicable in todays
> source routing cases).

Yup ..its different. you have used some of the ToS routing
conclusions for claiming diffrout scheme and hence, i made that
comment regarding scalability.

> What I don't agree (my view):
> - Just because a solution has scalability issues doesn't
> mean that that solution is not going to solve ANY
> problem.

Sorry for making such a statement. But you should also agree
that, you did not still clearly state *why we need diffrout?*

> Finally, you didn't tell me in what other approaches
> we can solve the same issues that the DiffServ-TE is
> trying to solve (with out letting control plane know,
> with out CSPF, with out connection-oriented MPLS etc etc).
First of all control plane work in Diffserv is incomplete.
what you want to do with *diffrout*-QoS-Routing, sneak-around
the congestion-area routing, and traffic balanced routing.

Let me suggest you a simple technique: Use *explicit routing* of
MPLS which is the simplese one for doing sneaking around work.

Doing dynamic QoS routing is very difficult and operators
generally dont prefer. But this is surely not a good argument :-).
i will support diffrout if you just explain me *why we need
diffrout*. I am reading all the 14 mails regarding diffrout but
still couldn't get a correct problem statement.

In the corner, I am too advocating a new idea which is contradictory
to diffrout. By taking SPF into account, an effective load balancing
can be done in diffserv architecture. I will get back to you once i get
done with an analytical model.

  



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