Subject: Re: [Diffserv] a question on edge-to-edge DiffServ flows

From: Jaeyoung Kim <[email-masked]>
Date: Tue, 7 Aug 2001 10:52:43 +0900

On Mon, Aug 06, 2001 at 12:38:31PM -0400, Keith Kim wrote:
> It sounds you are talking about something similar to 'maximum flow' 
> problem with multiple sources and sinks in a flow network, which
> is often a popular topic in an algorithm textbook.

Something different. The 'maximum flow' problem wants to solve the maximum
possible end-to-end throughput with a given set of link capacity by using all
possible paths from one source to one sink (multiple souce/sink can
be converted to single source/sink case). However, my problem is to
try to use only one path (routing path) of an e-to-e traffic flow.

> IMHO, you cannot narrow down the min-max throughput of each ingress/
> egress pair, enough to be able to use those bounds as a diffserv traffic
> engineering guideline.  If I were an ISP, I would measure the traffic
> amount for each ingress-egress pair at each ingress point, since I 
> would already know the egress point for each packet from its association
> with a particular VPN attached to the egress.

Yes, I think you're correct. The problem of my idea is that the min/max
bound often too wide to be a useful indicator for e-to-e traffic status.
However, I feel there's a certain area where the proposed idea is applicable.
That's why I'm searching for similar research and related papers.

About measuring traffic for each ingress-egress pair, sometimes it is
impossible to know a priori the egress point of incoming traffic at ingress
edge router. If a DiffServ class is mapped to a VPN service, the destination
can be easily obtained at ingress router. However, if a DiffServ class
is mapped to a certain service with many destinations, the situation is
different.

In this situation, I'm thinking that we need to mark the ID of ingress
router at the header of each packet when incoming a DiffServ domain so
that every egress router can distinguish and count the traffic for each
ingress-egress pair. Is there anyone to know similar research with
the source-marking/destination-counting edge-to-edge throughput monitoring
method?

Anyway, thank you for your valuable comments and ideas.

Sincerely,
Jay Kim

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---

From: Brian E Carpenter <[email-masked]>
Date: Wed, 08 Aug 2001 11:08:51 -0500

Please take this discussion to the diffserv-interest list...
http://www.ietf.org/mailman/listinfo/diffserv-interest

Thanks
   Brian