Improved Selective ACK Scheduling Optimization over Asymmetric Paths for CMT-SCTP

With the deployment of more and more resilience critical Internet applications, there is a rising demand for multi-homed network sites. SCTP is a general-purpose Transport Layer protocol that provides multi-homing feature. Concurrent Multipath Transfer with SCTP’s multi-homing support (CMT-SCTP), which is the extension of SCTP protocol, simultaneously transmits new data from a source host to a destination host via two or more end-to-end paths. This paper proposes an improved Selective Acknowledgement (SACK) scheduling optimization scheme for improving the transmission throughput in the concurrent multipath transfer (CMT) environment consisting of asymmetric paths. In the proposed scheme, the main contribution is that a multi-homed receiver senses bandwidth values of all available reverse paths and then distributes SACK packets to each path proportionally. From the simulation test, we can see that when the end-to-end propagation delays of paths varied, the application throughput of the proposed scheme could improve the application throughput under bit error rate and delay varied.