An efficient fuzzy based traffic policer for ATM networks

In Asynchronous Transfer Mode (ATM) networks, congestion can be caused by u npredictable statistical fluctuations of traffic flows and fault conditions within the network. If congestion: happens, then the network performance f or the already established connection will decrease. ATM networks use the p reventive congestion control mechanisms such as Usage Parameter Control (UP C) and Connection Admission Control (CAC) to avoid congested conditions. Kn owing that many sources in ATM networks have variable traffic stream with d ifferent QoS characteristics, traffic management functions become necessary to control the traffic flows within the network. By using the signaling pr ocedures at the call setup phase, the network and source reach an agreement for some traffic characteristic parameters. If the source violates the tra ffic parameters, then the probability of congestion increases. So the netwo rk must control the source traffic streams and detect well the violating ce lls. Therefore, fast detection of airy violating: source is one of the most important characteristics of a good traffic policer. In this paper we prop ose a fuzzy traffic policer with high ability in detection of violating sou rces. Our proposed fuzzy controller has two inputs, estimated passed mean c ell rate and the current state of the counter. If the output of fuzzy contr oller is 1, then the input cell is detected as violating cell, otherwise it is a non-violating cell. Simulation results obtained from two traffic sour ces, show that the proposed traffic policer has better selectivity than the conventional leaky bucket. It is observed that our proposed traffic police r has better ability for mean cell rate control, peak cell rate control and burst duration control. Furthermore: it is observed that the proposed traf fic policer outperforms the conventional leaky bucket specially when the dy namic behavior is considered.