All-optical switching has been considered as a natural choice to keep pace with growing fiber link capacity. One key research issue of all-optical switching is the design of optical buffers for packet contention resolution. One of the most general buffering schemes is optical priority queue, where every packet is associated with a unique priority upon its arrival and departs the queue in order of priority, and the packet with the lowest priority is always dropped when a new packet arrives but the buffer is full. In this paper, we focus on the feedback construction of an optical priority queue with a single $(M+2)\times (M+2)$ optical crossbar Switch and $M$ fiber Delay Lines (SDL) connecting $M$ inputs and $M$ outputs of the switch. We propose a novel construction of an optical priority queue with buffer $2^{\Theta (\sqrt {M})}$ , which improves substantially over all previous constructions that only have buffers of $O(M^{c})$ size for constant integer $c$ . The key ideas behind our construction include (i) the use of first in first out multiplexers, which admit efficient SDL constructions, for feeding back packets to the switch instead of fiber delay lines, and (ii) the use of a routing policy that is similar to self-routing, where each packet entering the switch is routed to some multiplexer mainly determined by the current ranking of its priority.

中文翻译：

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带有交换机和光纤延迟线的亚指数级光学优先级队列的构造

全光交换被认为是与不断增长的光纤链路容量保持同步的自然选择。全光交换的一个关键研究问题是用于分组争用解决的光缓冲器的设计。最普遍的缓冲方案之一是光优先级队列，其中每个数据包在到达时都与唯一的优先级相关联，并按优先级顺序离开队列，当新的数据包到达时，具有最低优先级的数据包总是会被丢弃，但是缓冲区已满。在本文中，我们专注于单个光优先级队列的反馈构造 $（M + 2）\次（M + 2）$ 光学纵横开关和 $ M $ 光纤延迟线（SDL）连接 $ M $ 输入和 $ M $ 开关的输出。我们提出了一种带有缓冲区的光优先级队列的新颖构造 $ 2 ^ {\ Theta（\ sqrt {M}）} $ ，与以前只有缓冲区缓冲的所有构造相比，它有了实质性的改进 $ O（M ^ {c}）$ 常量整数的大小 $ c $ 。我们的构造背后的关键思想包括：（i）使用先进的先进多路复用器，它允许高效的SDL结构，用于将数据包反馈到交换机而不是光纤延迟线；以及（ii）使用以下路由策略：与自路由类似，进入交换机的每个数据包都路由到某个多路复用器，主要由其优先级的当前等级决定。