Congestion Control Algorithms in High Speed Telecommunication Networks

Modern telecommunication and computer networks, including the Internet, are being designed for fast transmission of large amounts of data, for which Congestion Control Algorithms (CCAs) are very important. Without proper CCAs, congestion collapse of such networks is a real possibility. Random tele-traffic is a heterogeneous mixture of streams of data packets that have different quality-of-service requirements. By buffering submitted packets at gateway nodes we can regulate the rates at which data packets enter the network, although this may increase the overall packet delays to an unacceptable level. Therefore it is increasingly important to develop gateway mechanisms that are able to keep throughput of a network high, while maintaining sufficiently small average queue lengths. Several algorithms proposed recently try to provide an efficient solution to the problem. In one of these, Active Queue Management (AQM) with Explicit Congestion Notification (ECN), packets generated by different data sources are marked at the network’s gateways. In other algorithms, packets are dropped to avoid and control congestion at gateways. Thus, different senders of data can be required to reduce their traffic volume if needed. Communication with original data senders is maintained by returning marked acknowledgement packets. This paper presents a brief and breadth wise survey of major CCAs designed to operate at the gateway routers of multimedia telecommunication networks.