Extending equation-based congestion control to multicast applications

Abstract

In this paper we introduce TFMCC, an equation-based multicast congestion control mechanism that extends the TCPfriendly TFRC protocol from the unicast to the multicast domain. The key challenges in the design of TFMCC lie in scalable round-trip time measurements, appropriate feedback suppression, and in ensuring that feedback delays in the control loop do not adversely affect fairness towards competing flows. A major contribution is the feedback mechanism, the key component of end-to-end multicast congestion control schemes. We improve upon the well-known approach of using exponentially weighted random timers by biasing feedback in favor of low-rate receivers while still preventing a response implosion. We evaluate the design using simulation, and demonstrate that TFMCC is both TCP-friendly and scales well to multicast groups with thousands of receivers. We also investigate TFMCC's weaknesses and scaling limits to provide guidance as to application domains for which it is well suited.

Equation-based end-to-end single-rate multicast congestion control

“…Our focus in this paper is on TFMCC, a recently proposed equation-based single-rate MCC protocol [2,[6][7][8][9]. The equation used is adopted from the unicast TCPfriendly rate control (TFRC) [14] protocol.…”

“…The CLR is usually the receiver with the highest loss rate. Several single-rate multicast protocols have been proposed such as MTCP [13], PGMCC (Pragmatic General Multicast Congestion Control) [3], TFMCC [2], and ORMCC [1]. All these protocols have been shown to be TCP-friendly.…”

“…Another significant problem is that a single CLR can drag down the whole TFMCC session. For more thorough description of TFMCC, the reader is referred to [2,8]. ORMCC [1] is a more recent multicast rate control scheme, using the policy of AIMD approach.…”

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Among the recently proposed single-rate multicast congestion control protocols is transmission control protocol-friendly multicast congestion control (TFMCC;Widmer and Handley 2001; Widmer et al IEEE Netw 15:28-37, 2001), which is an equation-based single-rate protocol that extends the mechanisms of the unicast TCP-friendly rate control (TFRC) protocol into the multicast domain. In TFMCC, each receiver estimates its throughput using an equation that estimates the steady-state throughput of a TCP source.

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A Context-Aware Network Equipment for Dynamic Adaptation of Multimedia Services in Wireless Networks

“…Having simple scalable coding solutions operated on end-users devices is another solution [34] (the more data decoded by the receiver, the better the quality) but this solution does not prevent the bandwidth overuse since the total packets are emitted over the transmission network. Furthermore, the connection is end-to-end from the server to the users, without intermediate network element.…”