Theoretical Analysis of an Ideal Startup Scheme in Multihomed SCTP

SCTP congestion control includes the slow start mechanism to probe the network for available bandwidth. In case of path swap in a multihomed association, this mechanism may cause a sudden drop in throughput and increased message delays. By estimating the available bandwidth on the alternate path it is possible to utilize a more efficient startup scheme. In this paper, we analytically compare and quantify the degrading impact of slow start in relation to an ideal startup scenario. We identify three different scenarios, where a path swap could occur. Further, we identify relevant traffic for these scenarios. Our results point out that the most prominent performance gain is seen for applications generating high traffic loads, like video-conferencing. Moreover, the results show an increasing impact of an improved startup mechanism with increasing RTTs.