Blocking Probability Simulations for FDL Feedback Optical Buffers
Issue:
Volume 5, Issue 1, February 2016
Pages:
1-10
Received:
7 February 2016
Accepted:
17 February 2016
Published:
1 March 2016
Abstract: Asynchronous optical packet switching seems to a suitable transport technology for the next-generation Internet due to the variable lengths of IP packets. Optical buffers in the output port are an integral part of solving contention by exploiting the time domain. Fiber delay lines (FDLs) are a well-known technique for achieving optical buffers, and various optical buffer architectures using FDLs have been proposed. These are generally classified into two types of structure: feed-forward (FF) or feedback (FB). In the FF buffers, optical packets are delayed at the output ports by passing through step-increasing-length multiple FDLs to avoid contentions, and in the FB buffers, optical packets are delayed by being fed back in re-circulating loop FDLs to avoid contentions. We report the detailed characteristics of optical FB buffers with the Post-Reservation (PostRes) policy and clarify the superiority of the FB buffers through simulations. For comparison, we also show the characteristics of FBSI (FB with step-increasing-length FDLs) and FF buffers. We found that 1) the blocking probabilities in the FB buffer were about 10-2 lower than those in the FF buffer and 2) the blocking probabilities for the deterministic case in the FB buffer sharply dropped at D=1.0, where the packet length was equal to the FDL loop length. We carried out 108 packet simulations. The results can be applied to the design of WDM optical packet switches and networks with the maximum throughput.
Abstract: Asynchronous optical packet switching seems to a suitable transport technology for the next-generation Internet due to the variable lengths of IP packets. Optical buffers in the output port are an integral part of solving contention by exploiting the time domain. Fiber delay lines (FDLs) are a well-known technique for achieving optical buffers, and...
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