Flow Control and Routing in an Integrated Voice and Data Communication Network

Book excerpt: This paper considers a model of an integrated voice and data network. The model, which lends itself to analytic and algorithmic solution, is formulated as a convex optimization problem. The objective function comprises two types of functions: the congestion cost functions and the rate limitation functions. The congestion cost functions act to limit the average traffic entering into the network to values that would not cause network congestion. The rate limitation functions ensure that all conversations are fairly treated. The model can be generalized to solve problems of networks which handle n types of traffic that have different levels of delay sensitivity, where n> or = 2. A joint flow control and routing algorithm is constructed which uses short term average information on the network utilization to set the voice packet lengths and data input rates, and to determine the routes for each conversation. The voice packet lengths and data input rates are set in such a way as to achieve an optimal tradeoff between each user's satisfaction and the cost of network congestion. Additional protocols are specified for dealing with such issues as congestion avoidance and control, and for implementing flow control on a more dynamic basis than the quasi-static joint flow control and routing algorithm can handle.