| In recent years with the rapid development of Internet,mobile Internet and related technologies, the inherent defects of TCP’s is becoming more and more apparent, such as single path,whole data delay larger, vulnerable to the SYN flood attack, as well as the head of data stream block. Thus in the near future SCTP alternative to TCP become transport protocol in the next generation Internet has been paid highly attention and reached a consensus. To aggregate bandwidth, improve transmission throughput of end-to-end, Based on the SCTP some researchers had been proposed Concurrent Multipath Transfer (CMT) solution, namely SCTP-CMT.Reliability is one of the core issues of data transmission. Therefore, carrying out on reliable transmission researches in the Concurrent Multipath Transfer of the next generation Internet has important theoretical significance and application value.By now, there have been a lot of researchers for multistream and multihome of SCTP to achieve reliable transmission. These work were aimed at proposing a better solution on either routing or improving the receiving buffer block issue, but the existing solutions have disadvantages more or less, its main defects are:(1)most of the solutions was aimed at fast retransmission when path failure result in data loss, did not consider the time consumed by a fast retransmission occupy the total size of the data transmission time. (2) Most of solutions on congestion control of Concurrent Multipath Transfer assumes that receive buffer is infinite. But in fact there is impossible to have infinite receive buffer, and it has no practical significance and cannot be accurate reflection of the actual situation of the network environment under infinite receive buffer congestion control research, it is not rigorous.On the basis of existing research, this paper makes a further analysis, and introduces the "Redundant Transmission" conception; the concept of "Redundant Transmission" means choose a path from multipath as redundant path to assist the other path for transmission. Based on this, in view of the above two questions. (1) When a failure occurs, sender does not immediately enter the fast retransmission steps but receive the lost packets through the redundant path, since it reduces the time which is consumed from data loss to fast retransmission, and improve the throughput of the whole transmission process. (2) In congestion control, this solution makes further improvements when receive buffer is block, when packet loss occurs in a path; it does not affect the other path transmission window size and reduces the probability of receiving buffer congestion phenomenon. Simulation results show the accuracy and rationality of the model.Finally, the paper gives the summary of the subject and proposes the next research direction. |
