Performance Research On XCP For High Bandwidth Delay Network Model

The current trend shows that the future network presents a feather of high Bandwidth-Delay Product (BDP). When BDP increases, the performance of traditional TCP protocol will decline critically, and it not only be unable to use high bandwidth effiently, but also its transfer rate is unstable in high speed network, becoming the great barrier in implementation of new network applications. Based on the above problems, Dina Katabi provides a new eXplicit Control Protocol (XCP). XCP adopts an idea that the core routers can send the congestion level of bottleneck links to its terminals, achieving high bandwidth utilization, low queue delay, near zero drops and good extensibility. XCP has better performance than TCP in efficiency, fairness and stability, regardless of the traditional or BDP network.In this paper, we first analyse TCP's deficiencies, then introduce the details of XCP's framework and algorithm, and make some simulation experiments and performance analysis. XCP is a more comprehensive and practical protocol, and a strong competitor in future BDP network. So, we will study and enhance XCP intensively.There are two aspects of progressive work, as following:first, based on the researching for theαandβof XCP, we find thatαwill influence network utilization greatly, so we propose a enhanced algorithm that a should be adjusted according to current network; second, when XCP traffic and non-XCP traffic coexist in the same network, XCP routers can't calculate the occupied bandwidth of different flows, causing serious jitter with the bottleneck link utilization and the total throughput, then we propose an improved algorithm (NewXCP). Our simulations indicate that the enhanced algorithms can improve network utilization and maintain stability of the system.