SF-SCTP: a new transport protocol to support QoS for FCS applications

Abstract

The communication of Future Combat Systems (FCS), with rigid timing and reliability requirements, has posed a great challenge for the existing popular transport layer protocols such as TCP and UDP. The Stream Control Transmission Protocol (SCTP), first designed to transmit telephony signaling messages over Internet, is a promising transport layer candidate for FCS networks. The new SCTP features such as multi-homing, multi-streaming, and enhanced security can significantly improve the performance of FCS applications. In this paper, we propose modifications to the congestion control and multi-streaming parts of current SCTP specifications to allow the support of QoS for FCS applications. Multiple streams in an SCTP association provide an aggregation mechanism to accommodate heterogeneous objects, which belong to the same application but may require different types of QoS from the network. However, the current SCTP specification lacks an internal mechanism to support the preferential treatment among its streams. Our work introduces the concept of grouping SCTP streams into subflows based on their required QoS. We propose to modify the current SCTP to implement subflows (named SF-SCTP), each with its own flow and congestion mechanism to prevent the so-called false sharing problem. To improve the fairness of SF-SCTP towards the original SCTP, we integrate Fractional Congestion Control into the design. The throughput performance evaluation of SF-SCTP is studied through ns-2 experiments in a simplified Diff-Serv network. The simulation results prove the SF-SCTP's capability to support QoS among its streams, confirm the accuracy of the analytic models, and justify our effects to integrate FCC into SF-SCTP since it improves the fairness between SF-SCTP and the original SCTP.