Two-stage shared fiber delay line optical packet switch for contention resolution in optical packet-switching network

Abstract

Packet contention is a major issue in an optical packet-switching network. We focus on contention resolution using fiber delay lines (FDLs), which are used to buffer contended packets in order to forward these packets to the desired output port to some future time slots. Most of the existing optical buffering schemes are output based, which require a huge number of FDLs as well as a larger switch size and incur extra implementation cost. A shared FDL buffering approach is considered to reduce implementation cost. This paper proposes a two-stage shared FDL optical packet switch to resolve contention, where FDLs are implemented in two stages using extremely simple auxiliary switch. The performance of the proposed switch architecture is evaluated through simulation under trivial and bursty traffic condition, in terms of packet loss rate and average delay. Other performance parameters, such as cross-talk, insertion loss, switch time, etc., are also discussed. Simulation result shows that, the packet loss rate of the proposed architecture under heavy traffic load ( = 0.9) is between ~10−3 and ~10−4 for a 32×32 switch using 64 FDLs, and zero packet loss rate achievable with < 0.8.