Fuzzy Congestion Control In Packet Networks

Abstract

In this paper an adaptive fuzzy congestion control solution for active queue management in packet switched networks which use TCP to solve end-to-end flow control is described. It supports end-to-end control for packet data traffic between intermediate nodes, such as routers, in the network. In the presented solution, a fuzzy controller with an adaptive fuzzy membership function generation and tuning procedure and a multilevel hierarcical decision making method regulates the rejection probability of received packets on intermediate nodes to prevent buffer overflow and the rejection of all transmitted packets during congestion. In the simulations we compared a fuzzy controller with a fixed shape of membership functions with the fuzzy controller with adaptive membership functions. Membership functions were updated according to the incoming traffic in order to keep the equation form rule base as simple as possible. The simulation results showed that the developed adaptive control algorithm decreased the packet loss rate with a lower occupation of the buffer and increased the link utilisation via decreasing the retransmission rate more effectively.