Congestion controlling schemes for high-speed data networks: A survey

The data networks are basically designed with the aim of maximum throughput and fair resource allocation by managing available resources. A transport layer plays an important role in throughput and fairness with the help of congestion control algorithms (variants). This survey targets mainly congestion issues in high-speed data networks to improve efficiency at connection or flow level. Transmission Control Protocol (TCP) is a dominating transport layer protocol in the existing network because of its reliable service and deployment in most of the routers. A cause of congestion may be different in wired and wireless network and needs to be handled separately. Packet delay, packet loss and time out (RTO) are not caused by congestion in case of wireless network. This has been taken into account in our consideration. To overcome the dominance of TCP, Google proposed UDP based solution to handle congestion control and reliable service with minimum latency and control overhead. In the literature several methods are proposed to classify transport layer Protocols. In this survey congestion control proposals are classified based on situation handled by the algorithm such as pure congestion, link loss, packet reordering, path optimization etc. and at the end congestion control at flow level has been addressed.