Performance Analysis of Selective Minimum Delay Value (SMDV) Algorithm for Packet Contention Resolution of Optical Packet Switch

Abstract

Packet contention is a major issue in optical packet switching network and it is not a trivial task to resolve contention due to lack of optical RAM technology. In order to resolve contention optical buffering approach is used which is usually implemented using fiber delay line (FDL). Most of the existing optical buffering schemes are output-based which require huge number of FDLs as well as larger switch size that incur extra implementation cost. In this paper, shared FDL buffering approach is considered to reduce implementation cost. However, shared buffering scheme requires an effective scheduling algorithm to utilize the buffers efficiently. This paper proposes a new algorithm called selective minimum delay value (SMDV) to resolve contention of an optical packet switch. In SMDV, contended packets are assigned to fiber delay line (FDL) in such a way that no two contended packets release from FDLs destined for same output port at the same time. The performance of the proposed scheme is analyzed based on normalized throughput and delay under different traffic load. Simulation result shows that proposed scheme can achieve a normalized throughput of ~93.7% even at heavy traffic load of 0.9 for a 32×32 switch using 32 FDLs of different length.