Buffer Management for Shared Feedback Buffer-Type Optical Packet Switches

We design a buffer management scheme for shared feedback buffer-type optical packet switches. The buffer is of the fiber-delay-line type and handles variable-length optical packets. The buffer limits the number of feedbacks of a packet to avoid degradation of the physical characteristic. We try to reduce packet loss probability in the packet switch by adopting new buffer management methods in which void spaces at output ports are reduced, packets are aligned in the buffer to avoid contention at output ports, and buffer utilization is increased. Through simulation, we find that the proposed methods provide better packet loss probability and delay performance than existing methods. We show that the improvement is obtained when we use buffer structures in which a variety of delay lengths are installed. The proposed methods are also better when wavelength conversions are allowed and when unbalanced traffic enters.