Re: [RRG] Are we solving the wrong problem?

["Mark Handley" <M.Handley@cs.ucl.ac.uk>]

On Feb 19, 2008 10:08 AM, Geoff Huston <gih@apnic.net> wrote:

> I can't see that Eliot - it seems close to Shim6 in some ways, although
> here Mark is advocating a "shim' at the session / transport level of the
> protocol stack rather than at the IP level. I have my concerns at the
> robustness and effeciency of a session level approach and see more merit
> at the IP level, but thats a personal perspective. But thats orthogonal
> to the properties of a routing system.

Well, it's not really orthogonal, because they have very different
emergent behaviour, so leave different amounts of work for the routing
system to do.

The specific reason for layer 4 is that you need to stripe data across
multiple *congestion controlled* paths for the traffic to
self-traffic-engineer. Only then do the bytes to be transfered
actually move away from the congested paths to the uncongested paths
in a stable manner.  I don't believe you can get this unless the
congestion control part of the stack is aware of the different
paths/addresses and load-balancing across them.

Cheers,
Mark

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