The problem isn't a particular type of traffic in isolation, its usually the impact of one network user's traffic on all the other network user's traffic sharing the same network.
Network Quotas for Individuals - A better answer to the P2P bandwidth problem?
http://www.greatplains.net/research/workshops/2004%20Annual%20Meeting/Network.Quotas2.ppt Can ISPs and P2P users co-operate for improved performance: http://www.net.t-labs.tu-berlin.de/papers/AFS-CISPP2PSCIP-07.pdf P4P: Proactive Provider Assistance for P2P http://cs-www.cs.yale.edu/homes/yong/publications/P4PVision_P4PWG.ppt
