Congestion control train-wreck workshop at Stanford: Call for Demos

> [...]

If there is no congestion, then this conversation serves no purpose.
I'd like one infinite improbability drive too.

Sure. When mine arrives, I'll drop it into my matter replicator so you
can have one. :slight_smile:

> Let's say our example student is capable of generating 95% of flows by
> virtue of having access to 95% of the IP endpoints in the example
> network. How do you envision the OS notion of "user" helping you
> implement a per-user notion of fairness on the backbone?

That's why I don't think operators care about "users" or "endpoints" but
they do care about who is paying the bills. Operators care about the
relative "fairness" between bill payers, not flows, sessions or users.

Suppose MIT has a /8, Harvard as a /16; if MIT figured out they could get
more backbone bandwidth than Harvard by multiplexing its "flows" across
more addresses, and starving Havard students of backbone capacity.
Suppose Harvard was paying for 50% of the backbone cost, while poor
MIT could only afford to pay for 10% of the backbone cost.

If the congestion point was always at the backbone edge, you might be
able to accomplish this by making Harvard's connection bigger than MIT's
connection. But lets imagine instead, during periods of little congestion
you want both Harvard and MIT to use as much of the backbone as they can,
and only when there is congestion do you want to "share" the backbone
congestion "fairly" between them.

Yes, that's the notion that I was trying to convey.

I agree that operators don't care about users, my reason for steering
the conversation back toward them is that what kicked this sub-thread
off was the assertion that knowledge of user by the OS at a TCP
endpoint could somehow provide relevant information for resource
allocation in a network such that congestion is divided among
users. Techniques for trying to impose how congestion is "fairly"
shared among flows exist and aren't what we're talking about. Could a
technique be developed that used a notion of "user" in a network?
(From Fred's reply, I think that's what we're talking about.) I'd
argue that if it could it would be complex and therefore unsuitably
fragile in a service provider environment, and would lose all
relevance the moment a congestion point at an administrative boundary
was crossed.