Modeling Network-Level Impacts of P2P Flows

It has been clear for a long time that P2P applications represent a large proportion of the load on the network infrastructure. This is why significant research efforts have been devoted to reducing this load, in the form of ISP friendly P2P solutions. These solutions focus on the volume of the traffic as opposed to the number of network flows. At the same time, we are witnessing a great demand for more and more intelligence in the network such as flow based monitoring and application recognition, which have an overhead that depends on the number of flows and not on the volume of the traffic. Besides, the implementation of this intelligence is moving from the access layer towards the distribution and core layers. We show through measurements that the typical devices serving in the different layers of the infrastructure are not sufficiently scalable in terms of the number of flows, and, most importantly, the combined effect of an increase in the access layer bandwidth together with an increase in the P2P (e.g., BitTorrent) population will practically disable the intelligent networking capabilities. Our conclusion is that a novel focus needs to be incorporated into P2P research that concentrates on reducing the number of network flows generated by P2P applications.