Performance study of various packet scheduling algorithms for variable-packet-length feedback type WDM optical packet switches

In this paper, we investigate the switching performance of feedback (FB) type wavelength division multiplexing (WDM) optical packet switches (OPSes) with various packet scheduling algorithms that determine the buffer entrance sequence of packets arriving at the input end of the switches. Five different packet scheduling algorithms have been applied to the FB type WDM OPSes. It is observed that OPSes incorporated with shortest packets first (SF) and oldest packets first (OF) algorithms will yield better switching performance. Next, we observe that packet scheduling algorithms have stronger influence on switching performance when they are applied to the primary output buffers than to the re-circulated buffers. Moreover, we demonstrate that by appropriately employing the suitable packet scheduling algorithms in the primary output buffers and re-circulated buffers, the benefits of packet scheduling algorithms could be significant. Hence, the switching performance of FB type WDM OPSes could be greatly improved simply by employing the appropriate packet scheduling algorithms