A New Architecture Of Buffers Based On FDL And TWC

Due to the influence of electronic bottleneck, the capacity and bandwidth of switch network is constrained, thus the optical packet switch, in which the speed and the capacity can be suitable to the explosive growth of Internet traffic, becomes the main branch of the switch fabrics. In packet switching networks, packet contention occurs when two or more packets contend for the same output at the same time, with an unsuitable implementation, the packets will be lost and the packet loss probability increases. Thus it is important to bring buffers into consideration to avoid contention. The buffers, unlike the random-access-memory (RAM) in electronic domain, are not available yet in optical domain, thus three other ways are brought into research which are fiber delay line, tunable wavelength convertor and deflection routing.This paper focuses on the buffers in key nods, firstly the technology of buffers are analyzed and compared to get its own relative merits.Secondly, it can be divided into two categories:output buffering and feedback buffering, depending on the place of the buffers in the switch fabric. The two kinds of buffers have been evaluated by packet loss probability and mean packet delay through simulations.In the summary, a structure, including output buffering and feedback buffering, based on the KEOPS switch with a broadcast-select fabric, is formed. The performances (mean packet delay and packet loss probability) are investigated by a suitable queue model with different kinds of buffers.It is concluded by simulations as following:It is concluded by simulations as following:1. Output buffering can improve the situation of packet contention, and the packet loss probability decreases as the scale of fiber delay lines increase;2. Feedback buffering can utilize fewer mount of FDLs than output buffering to achieve the same packet loss probability;3. The mean packet delay increases as the FDLs are involved in the switch fabric, but when the load is steady, the mean packet delay is to a fixed value;4. The packet loss probability is brought down when the wavelength convention is added into the switch fabric without any influence on mean packet delay;5. It can be realized that the performance satisfy the requirement of the common communications, with a suitable scale of buffers in this paper.