SCTP Congestion Window Overgrowth During Changeover

Unlike TCP, the Stream Control Transmission Pro- tocol (SCTP) supports IP multihoming at the trans- port layer. SCTP allows an association to span multi- ple local and peer IP addresses, and allows the ap- plication to dynamically change the primary desti- nation during an active association. We present a problem in the current SCTP (RFC2960) specifica- tion that results in unnecessary retransmissions and "TCP-unfriendly" growth of the sender's congestion window during certain changeover conditions. The problem is presented in a specific case, and an algo- rithm we name the Rhein algorithm is proposed and analyzed as a possible solution.