TCPeer: Rate Control in P2P over IP Networks

The prevalent mechanism to avoid congestion in IP networks is the control of the sending rate with TCP. Dynamic routing strategies at the IP layer are not deployed because of problems like route oscillations and out-of-order packet deliveries. With the adoption of P2P technology, routing is done also in these overlay networks. With multi-source download protocols peers upload and download to/from other peers in parallel. Based on congestion pricing for IP networks this paper proposes a rate control algorithm for P2P over IP networks. A peer adopts the functionality of TCP and extends the congestion window mechanism with information from the overlay network. Thus, a sending peer is able to shift traffic from a congested route to an uncongested one. This change in the rate allocation will be balanced by other peers in the overlay. Hence, the receiving peers experience no degradation of their total download rate.