Methods, Tools, and Observations on Flow Control in Packet-Switched Data Networks

Flow control covers several concepts. In an end-to-end connection, it intends to adapt sender´s output to receiver´s capabilities. In a shared resources communication network, it attempts to prevent congestion by restricting traffic flows. Flow control mechanisms are built with a small number of basic throttling tools. However, they are always tied into a resource management problem, which depends on a large variety of environmental parameters. Techniques used in end-to-end connections are summarized. Congestion control in store-and-forward packetswitching networks is covered extensively, and techniques used or proposed are discussed. Memoryless networks, such as broadcast local networks are shown to be simpler systems in the area of flow control. In conclusion, arguments are made for a service oriented approach, which would optimize resource usage through differentiated service characteristics.