A congestion avoidance mechanism in multimedia transmission over MANET using SCTP multi-streaming

Abstract

Congestion is a challenging problem in Mobile Ad hoc Networks (MANETs) because of resource constraints, and dynamic routing. Congestion control is a big concern in achieving fairness between optimal network resource utilization and end-to-end flow control. In MANETs, with shared resources, when multiple senders contend for the same link bandwidth, data rate by each sender must be adjusted to avoid network overload which causes Quality of Service compromises. Strict ordering of data transmission in Transmission Control Protocol (TCP) causes poorer performance during data transmission in MANETs. Unlike TCP, Stream Control Transmission Protocol (SCTP) has a built-in multi-streaming feature to alleviate this issue caused by strict data ordering when using a single data stream within a transport connection. In this paper, we propose a Congestion Avoidance Mechanism over MANET routing based on Data Priority and Streaming Delay Weights (SDWs) which also utilizes SCTP multi-streaming (namely CAM-SCTP). Our proposal implements a Priority Manager (PM) to effectively select a stream to transmit data based on the data priority and by dynamically computing an SDW value per node. Experimental evaluation of the CAM-SCTP is performed for three different data types. The results show improvement in throughput for all data types while maintaining lower jitter, loss, and overhead.