An Analysis of Resequencing Delay of Reliable Transmission Protocols over Multipath

Multipath transfer utilizes multiple independent end-to-end paths to improve the total transmission throughput. Reliable transmission protocols as TCP and SCTP suffer resequencing delay due to asynchronous packet arrivals at the receiver as a result of packet reordering. The resequencing delay deteriorates the performance of some delay-sensitive applications. In this paper, we make an analysis of the mean resequencing delay for an average packet in a typical multipath transfer scenario. In the scenario, the path delay is assumed to be constant while distinct to each other. In consideration of path selecting probability, path delay and bandwidth, a model of the mean resequencing delay for an average packet in a long-term session is derived. The model is evaluated with the aid of SCTP CMT, which is a technically mature multipath transfer instance. It is shown that the results computed from the analytical model agree well with the output of the simulations. We expect the model can be used as a reference of resequencing delay estimation, aiding multipath transfer algorithms to get a better performance.