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Virtual output queueing (VOQ) is the technique used in input-queued switches where rather than keeping all traffic in a single queue, separate queues are maintained for each possible output location. It addresses a common problem known as head-of-line blocking. == Description == In VOQ each input port maintains a separate queue for each output port. It has been shown that VOQ can achieve 100% throughput performance with an effective scheduling algorithm. This scheduling algorithm should be able to provide a high speed mapping of packets from inputs to outputs on a cycle-to-cycle basis. The VOQ mechanism provides throughput at a much higher rate than the crossbar switches without it. There are many algorithms for design and implementation of fast VOQ. Nick McKeown and a group at Stanford University for example published a design in 1997. Quality of service and priority are extensions found in literature of the same time. VOQ scheduling is often referred to as "arbitration" (resolving the concurrent access wishes), whereas the ordering of packets ("packet scheduling") is an additional task following the VOQ arbitration. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Virtual output queueing」の詳細全文を読む スポンサード リンク
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