XCP-i: "eXplicit Control Protocol" for the Interconnection of Heterogeneous High-Speed Networks
Abstract
eXplicit Control Protocol (XCP) is a transport protocol that efficiently controls the sender's congestion window size thus avoiding the slow-start and congestion avoidance phase. XCP requires the collaboration of all the routers on the data path which is almost impossible to achieve in an incremental deployment scenario of XCP. If not, XCP's performances are worse than those of TCP thus limiting dramatically the benefit of having XCP running in some parts of the network. In this paper, we address this problem and propose XCP-i which is operable on an internetwork consisting of XCP routers and traditional IP routers without loosing the benefit of the XCP control laws which allow the congestion window to jump directly to the optimal size. The simulation results on a number of topologies that reflect the various scenario of incremental deployment on the Internet show that XCP-i outperforms TCP on high-speed links.