Improving the Acknowledgment Handling of SCTP

In general, the Stream Control Transmission Protocol (SCTP) delays the sending of acknowledgments. For specific cases, this results in non-optimal protocol behavior. Therefore, the protocol specification defines several exceptions that allow the receiver of an SCTP packet containing user data to send the corresponding acknowledgment without delaying it. However, all these exceptions only take the status at the user data receiver side into account and thus cannot cover all relevant situations. To overcome this limitation, the authors have proposed a generic mechanism allowing the sender of an SCTP packet containing user data to indicate, that the corresponding acknowledgment should not be delayed. This paper analyzes the benefits of using this sender side mechanism under several conditions.