Performance Analysis of Optical Packet Switches with Reconfiguration Overhead

Kuan-Hung CHOU  Woei LIN  

IEICE TRANSACTIONS on Communications   Vol.E94-B   No.6   pp.1640-1647
Publication Date: 2011/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.1640
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fundamental Theories for Communications
stochastic analysis,  optical communication,  discrete-time system,  stochastic decomposition,  batch arrival,  

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In optical packet switches, the overhead of reconfiguring a switch fabric is not negligible with respect to the packet transmission time and can adversely affect switch performance. The overhead increases the average waiting time of packets and worsens throughput performance. Therefore, scheduling packets requires additional considerations on the reconfiguration frequency. This work intends to analytically find the optimal reconfiguration frequency that minimizes the average waiting time of packets. It proposes an analytical model to facilitate our analysis on reconfiguration optimization for input-buffered optical packet switches with the reconfiguration overhead. The analytical model is based on a Markovian analysis and is used to study the effects of various network parameters on the average waiting time of packets. Of particular interest is the derivation of closed-form equations that quantify the effects of the reconfiguration frequency on the average waiting time of packets. Quantitative examples are given to show that properly balancing the reconfiguration frequency can significantly reduce the average waiting time of packets. In the case of heavy traffic, the basic round-robin scheduling scheme with the optimal reconfiguration frequency can achieve as much as 30% reduction in the average waiting time of packets, when compared with the basic round-robin scheduling scheme with a fixed reconfiguration frequency.