Abstract-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.

No abstract

It is well-known that the BitTorrent file sharing protocol is responsible for a significant portion of the Internet traffic. A large amount of work has been devoted to reducing the footprint of the protocol in terms of the amount of traffic, however, its flow level footprint has not been studied in depth. We argue in this paper that the large amount of flows that a BitTorrent client maintains will not scale over a certain point. To solve this problem, we first examine the flow structure through realistic simulations. We find that only a few TCP connections are used frequently for data transfer, while most of the connections are used mostly for signaling. This makes it possible to separate the data and signaling paths. We propose that, as the signaling traffic provides little overhead, it should be transferred on a separate dedicated small degree overlay while the data traffic should utilize temporal TCP sockets active only during the data transfer. Through simulation we show that this separation has no significant effect on the performance of the BitTorrent protocol while we can drastically reduce the number of actual flows. Keywords component • BitTorrent • small degree overlay Acknowledgement M. Jelasity was supported by the Bolyai Scholarship of the Hungarian Academy of Sciences.