Research On Transfer Policy With Partial Path For SCTP-CMT Using Path Weight

With the development of the Internet, For example, a large number of online cinema sites and video telephony are gradual applied in the Internet, better service of quality and a higher performance requirements are provided by Internet users. TCP, which is mainly relied on by web services at present, is difficult to meet the requirements of large-scale real-time media. SCTP, which is multihoming and multistreaming, is a new Transfer Protocol, and has be applied gradually in the Internet. Although it is not used widely now, the IETF has considered it as the mainly Transfer Protocol in the future to study. CMT based on SCTP is a hot field.As a new Transfer Protocol, there is some shortcomings in some fields, and now SCTP-CMTs mainly shortcoming reflect in the following ways:1)when the data is translated in the associate using SCTP-CMT, the performance, such as throughput, couldn’t reach optimization for some bad paths in the associate;2)the existing retransmission policies are depend on one parameter(lossrate, cwnd, ssthresh) to select path for data, it is limitations.To solve these two problems this paper introduces the concept of weight of path(Path Weight),and it refers to the impact throughput of path by delay and lossrate, and is Calculated by a function which has two parameter (delay and lossrate).Based on this, this paper proposes two solutions for these two issues:1) propose the solution, CMT-PW(CMT-Path Weigh) which is based on Path Weight, to select paths in the CMT associate, and it proved that the CMT-PW is better than Original SCTP-CMT In the respect of throughput by experiment;2)propose a Retransmission policy, RTX_PW(Path Weight) which select path for retranslate data basing on the Path Weight. It is best among RTX_CWND, RTX_SSTHRESH, RTX_PW in the respect throughput and times of retranslate, and reduce the times of receive buffer block. It is proved by simulation that this policy is Reasonable and advanced.Finally, the summary of this subject was given in this paper and a suggestion to the research work of future was outlooked in this paper too.