Can P2P applications learn to play fair on networks?

Sun Oct 21 19:31:26 UTC 2007

Sean Donelan wrote:
> So what about the other 490 people on the node expecting it to work?  Do 
> you tell them sorry, but 10 of your neighbors are using badly behaved 
> applications so everything you are trying to use it for is having 
> problems.  

Maybe Comcast should fix their broken network architecture if 10 users 
sending their own data using TCP (or something else with TCP-like 
congestion control) can break the 490 other people on a node.

Or get on their vendor to fix it, if they can't.

If that means traffic shaping at the CPE or very near the customer, then 
perhaps that's what it means, but installing a 3rd-party box that sniffs 
away and then sends forged RSTs in order to live up to its advertised 
claims is clearly at the "wrong" end of the spectrum of possible solutions.

 > Maybe Comcast should just tell the other 490 neighbors the 10
 > names and addresses of poorly behaved P2P users and let the neighhood
 > solve the problem.

Maybe Comcast's behavior will cause all 500 neighbors to find an ISP 
that isn't broken. We can only hope.

> Is it reasonable for your filesharing of your family photos and video 
> clips to cause problems for all the other users of the network?  Is that 
> fair or just greedy?

It isn't fair or greedy, it is a bug that it does so. Greedy would be if 
you were using a non-congestion-controlled protocol like most naive 
RTP-based VoIP apps do.

Matthew Kaufman
matthew at eeph.com