Congestion Control and an Analysis of TCP - friendly Rate Control

This paper presents a history of congestion control research and an analysis of a specific rate-based congestion control protocol, TCP-friendly rate control (TFRC). Two taxonomies of congestion control mechanisms are presented, and later used to classify general end-to-end congestion control schemes including window-based and rate-based methods. The classic TCP congestion control mechanisms are introduced as an instance of window-based congestion control. To address the research in congestion control for UDP flows, we discuss datagram congestion control protocol (DCCP) and the congestion manager (CM). Implemented in DCCP, TFRC is examined in detail for its TCPfriendliness and ability to provide smooth transmission for the applications. The sender’s and receiver’s protocols are presented using AP notation, and the equations used in the protocols are analyzed for their conduciveness to TCP-friendliness and smooth transmission. Lastly, two empirical studies of TFRC performance are summarized to validate the effectiveness of this protocol.