Research On The Key Technologies Of Concurrent Multipath Transfer Based On SCTP

With the rapid development of communication technology, customers’demand for bandwidth is increasingly high. Concurrent multipath transfer (CMT) uses multiple paths to transfer data concurrently, which can effectively expand bandwidth. SCTP is one of the best ways to realize CMT because of it’s multihoming feature.Concurrent multipath transfer based on SCTP (CMT-SCTP), currently, is still on the stage of theory research. It is not mature enough because of the following two problems. One is the TCP-friendly problem caused by congestion control of standard SCTP, the other is the buffer blocking problem caused by quality difference of each path.This thesis aims to make profound analysis on the above two problems. Regarding the TCP-friendly problem, a congestion control method based on resource pooling (CMT/RP-SCTP) is proposed. The method makes the set of all paths behave as one large virtual path, taking the interaction between different paths into account. Considering the buffer blocking problem, a buffer processing method based on buffer splitting is proposed. The method distributes the buffer space of sender and reciever for each path evenly and maintains a balance of data tranmission among multiple available paths. Furthermore, a packet scheduling algorithm based on path quality is proposed which considers the available parameters of each path such as bandwidth, packet lose rate and round trip time. Based on these parameters, it can efficiently allocate the number of packets transmitted by each path.NS-2is applied in this thesis to simulate the above methods. Simulation results show that, streams of CMT/RP-SCTP can fairly share bandwidth with other streams. Furthermore, improved CMT-SCTP can effectively avoid the throughput degradation caused by buffer blocking.