Performance of Network Redundancy Mechanisms in SCTP

One of the ambitions when designing the Stream Control Transmission Protocol was to o er a robust transfer of tra c between hosts. For this reason SCTP was designed to support multihoming, which presumes the possibility to set up several paths between the same hosts in the same session. If the primary path between a source machine and a destination machine breaks down, the tra c may still be sent to the destination, by utilizing one of the alternate paths. The failover that occurs when changing path is to be transparent to the application. This paper describes the results from an experiment concerning SCTP failover performance, which means the time between occurrence of a break on the primary path until the tra c is run smoothly on the alternate path. The experiment is performed mainly to verify the Linux Kernel implementation of SCTP (LK-SCTP) and is run on the Emulab platform. The results will serve as a basis for further experiments. The experiment is performed in a network without concurrent trafc and in conclusion the results from the experiment correspond well to the values found in other studies and they are close to the theoretical best values. As expected the parameter Path.Max.Retrans has a great impact on the failover time. One observation is that the failover time and the max transfer time for a message are dependent upon the status in the network when the break of the primary path occurs.