Research And Implementation Of Stream-Path Binded CMT

The growing availability of multiple network interfaces on both mobile and fixed hosts makes concurrent multipath transfer (CMT) an appealing option to improve the performance of increasingly bandwidth-hungry multimedia applications. Concurrent multipath transfer (CMT) uses the Stream Control Transmission Protocol's (SCTP) multihoming feature to simultaneously transfer data across multiple end-to-end paths in a multihomed SCTP association. This dissertation proposes an enhanced CMT, which aims at binding one of the multiple data streams with one of the multiple paths. The certain data stream can only be transferred on the certain path.The dissertation is organized as follows, in chapter 2 we specify SCTP, which is a multihome-aware transport protocol used by CMT. We analyze SCTP with several aspects, including its architecture, basic function, packet format and the state diagram. Then in chapter 3, we first specify some achievements made with CMT. Researches on current CMT mainly focus on traffic distribution at the sender and packets disorder at the receiver, presented with several algorithms for load balancing and path independent congestion control, which greatly improved the performance. However, the current CMT uses a per-packet scheduling policy: the sender selects a path for each single packet independently. In high error environment, one path's failure will affect the deliver for all streams, which cannot fit into high error topology very well, and can easily induce receive buffer blocking. We demonstrate some deficiencies with the current CMT, and an enhanced protocol for concurrent multipath transfer is proposed. The enhancement uses a new per-stream scheduling policy: a CMT sender will select a path for each single stream, thus can avoid the receive buffer blocking. The enhanced CMT can be suitable for streams with different priorities. Together with a stream scheduler, it will provide better service. Chapter 4 and 5 give the enhancement's implementation in Linux, based on the Lksctp project, and testing with a multi-thread FTP application in a simple experimental setup. Finally, chapter 6 concludes the dissertation and outlines the future work.