Subject: constraint distribution protocol

From: Jon Crowcroft <[email-masked]>
Date: Wed, 21 Oct 1998 07:31:16 +0200

thinking about higher level call admission and qos routing scalablity
- it seems to me that several of the neat algorithms around might
scale adequeately for qos routing provided the scope of the links and
metrics they considered for alternate paths were constrained. but then
they sould be in any case for lots of reasons (policy, higher level
call admission, fault tolerance etc)....

the problem is that  a lot of these reasons traverse inter-domain
boundariies so we cannot just split the problem in the "usual" way
between intra-domain qos routing an inter-domain - we need a seperate
scheme for distributing constraints for qos routin that is independant
of routing protocols - i am making the same argument elsewhere for a
protocol for distributing current traffic conditions to areas of the
network that don't currently share flows with the reporting region, 
and in fact the properties of these two protocols might be quite
similar - basically, they are like link state in advertisement, but
must summarise based on region, and have source, sink and transit
filtering like BGP.....

a suitable case for nimrod....

j.

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From: Masataka Ohta <[email-masked]>
Date: Sun, 25 Oct 98 11:21:04 JST

Jon;

> call admission, fault tolerance etc)....

I'm afraid that you miss an important point.

Cost may be advertised. End users may have policy. But...

What you call policy on qos routing is bundled sales and, in most
contries, against anti trust laws.

> must summarise based on region,

We do need link state advertisement or its equivalent for QoS routing.

But, then, there is no point to have multiple link state protocols
with syntactical differences only.

> and have source, sink and transit
> filtering like BGP.....

Do you think BGP-style policy management scales?

							Masataka Ohta