Photonic Buffer Architecture to Support Prioritized Buffermanagement for Asynchronously Arriving Variable Length Packets

We study photonic packet switching architecture that enables high node throughput and provides priority services. While an ultra-high-speed address-lookup capability can be realized in the optical domain for a photonic packet switch, the optical buffer must be managed in the electrical domain. In this paper, we propose a photonic buffer architecture that can support prioritized buffer management schemes with less complexity, so that the capability for ultra-high-speed packet forwarding can be sustained in the photonic packet switch. We propose the vPBSO (Variable-length-packet-capable Partial Buffer Sharing with Overwriting) method, which is a prioritized buffer management scheme for providing DiffServ (Differentiated Services) Assured Forwarding. It can handle asynchronously arriving variable-length packets. vPBSO is based on a single queue, and its complexity is O p , where p is the number of levels of drop precedence (i.e., the number of priority classes). We show that at lower arrival rates, vPBSO provides better performance than vPBS (our extension to the existing method, called PBS, which is a prioritized buffer management method for synchronously arriving fixed-length packets) for high-priority packets, and the performance for low-priority packets is also better or at least almost the same. It is also shown that once the appropriate control parameter values for vPBSO and vPBS are determined and appropriate buffer management scheme is selected depending on the arrival rate of packets, we can achieve high-performance prioritized buffer management, which can be realized by some traffic load estimation method. vPBSO is especially effective when the arrival rate of higher priority packets is lower Hiroaki Harai and Masayuki Murata than that of lower priority packets, which is a likely situation in the prioritized system.