Variable length virtual output queue based fuzzy congestion control at routers

Internet routers play an important role during congestion. Most of the Internet routers have buffers at input and output ports, which hold the packets in the time of congestion. An active and efficient management of buffers is critical to minimize the congestion. However, queue management becomes very complex because of dynamics of input packets. We direct out attention to the variable length virtual queues as, to the best of our knowledge, all the queue management schemes available in the literature focus on fixed queue limit. Recognizing the fact that most of the Internet today runs drop-tail gateways we propose a modification to the drop-tail algorithm, based on Fuzzy logic control principles, which makes it a generic active queue management scheme in TCP/IP networks. The obtained simulation results are encouraging as they show low packet loss and high utilization of the buffers in comparison to drop-tail.