Re: [e2e] opening multiple TCP connections getting popular

From: Bob Briscoe <rbriscoe(at)jungle.bt.co.uk>
Date: Thu Aug 30 2007 - 19:05:16 EDT

Detlef,

At 19:20 30/08/2007, Detlef Bosau wrote:
>Bob Briscoe wrote:
>>
>>This possibly sounds like a misinterpretation of the example I gave in my
>>(very belated) reply (8 Aug) to your tsvwg email on a similar subject.
>>
>>I explained that the solution I propose doesn't rely on identifiers at
>>all. It reveals info about congestion being caused downstream in the
>>headers passing between any two economic entities (whether user and
>>provider or network to neighbouring network). That matches the pairwise
>>bilateral contracts people have.
>
>Do they?
>
>Always?

Give an example where they don't?

Trilateral (or worse) contracts are rarely if ever entered into by any party with any desire to apportion blame for failings. Note that multiple bilateral contracts with different parties for components of the same service are still all bilateral.

>And if so, why don´t you use the Congestion Manager (IIRC Seshan et al.?)
>or similar techniques in those situations?

I assume by "those situations" you mean where an end-user has mulitple connections being policed in bulk by her provider.

Indeed, a superficially CM-like object would become v relevant to manage the tradeoffs between different connections. But it wouldn't actually be doing the same thing as the CM.

The CM was only across connections to the same remote endpoint (I believe), to ensure one connection benefited from knowledge other connections had gleaned about the same path (although endpoints are never sure two connections share the same path because of the prevalence of equal cost multipath routing).

The thing that would be needed across all a user's connections in my case would be best described as a policy mediator. It would have to track the remaining allowance the policer contained and ensure that each connection was weighted to get the most out of this policed access over time (taking into account how each app might have weighted its own connections). It wouldn't need to be monitoring paths like the CM does.

Bob

>--
>Detlef Bosau Mail: detlef.bosau@web.de
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>

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Bob Briscoe, <bob.briscoe@bt.com> Networks Research Centre, BT Research B54/77 Adastral Park,Martlesham Heath,Ipswich,IP5 3RE,UK. +44 1473 645196 Received on Thu Aug 30 19:52:32 2007