Optimum Transmission Window for EPONs With Limited Service

This paper studies the Ethernet passive optical network (EPON) with limited service. The transmission window (TW) is limited in this system to guarantee a bounded delay experienced by disciplined users and to constrain malicious users from monopolizing the transmission channel. Thus, selecting an appropriate TW size is critical to the performance of EPON with limited service discipline. In this paper, we develop an M/G/1 queuing model with vacation times and limited-service discipline to investigate the impact of TW size on packet delay. A distinguishing feature of this model is that there are two queues in the buffer of each optical network unit (ONU): one queue is inside the gate and the other one is outside the gate, from which we derive the generalized formula of mean waiting time. Furthermore, based on the service-level agreements of users and the Chernoff bound of queue length, we provide a simple rule to determine an optimum TW size for limited-service EPONs. The analytic results reported in this paper are all verified by simulations.