Can P2P applications learn to play fair on networks?

Thu Oct 25 17:09:01 UTC 2007

On Thu, 25 Oct 2007, Marshall Eubanks wrote:
> I have raised this issue with P2P promoters, and they all feel that the
> limit will be about at the limit of what people can watch (i.e., full
> rate video for whatever duration they want to watch such, at somewhere 
> between 1
> and 10 Mbps). From that regard, it's not too different from the limit 
> _without_ P2P, which
> is, after all, a transport mechanism, not a promotional one.

Wrong direction.

In the downstream the limit is how much they watch.  The limit on how 
much they upload is how much everyone else in the world wants.

With today's bottlenecks, the upstream utilization can easily be 3-10 
times greater than the downstream.  And that's with massively asymetric 
upstreams capacity limits.

When you increase the upstream bandwith, it doesn't change the 
downstream demand.  But the upstream demand continues to increase to
consume the increased capacity. However big you make the upstream, the 
world-wide demand is always greater.  And that demand doesn't seem
to be constrained by anything a human might watch, read, listen, etc.

And despite the belief P2P is "local," very little of the traffic is 
local particularly in the upstream direction.

But again, its not an issue with any particular protocol.  Its how does
a network manage any and all unbehaved protocols so all the users of the
network, not just the few using one particular protocol, receive a fair 
share of the network resources?

If 5% of the P2P users only used 5% of the network resources, I doubt
any network engineer would care.