Augment SCTP multi-streaming with pluggable scheduling

Stream Control Transmission Protocol (SCTP) introduces the multi-streaming feature to avoid the head-of-line (HOL) blocking problem of TCP and facilitate the transport of signaling messages over the Internet. However, the current protocol specification does not define how multiple streams should be scheduled and implementations are different across platforms. They typically choose either round-robin or first-come-first-served. Such fixed choices may not satisfy the demands of different applications and limit the flexibility of the protocol. In this paper, we propose to augment the multi-streaming feature of SCTP with pluggable scheduling so that users can customize the multi-stream scheduling algorithm of SCTP to satisfy their application-specific demands. We implement our proposal in the Linux kernel and show that this extension greatly increases the flexibility of SCTP and brings visible performance enhancements. This is the first work that demonstrates the effectiveness of pluggable SCTP multi-stream scheduling through real implementations and testbed experiments. Our proposal requires modifications only on the sender side and incurs no interoperability or fairness problems. Hence, it is safe and convenient to be deployed in the current Internet.