输入排队交换中的变长调度算法分析

Analysis of Variable-length Packet Scheduling in Input-queued Switches

目前在高速路由器和交换机等网络互联的核心设备中广泛采用了交叉开关(Crossbar)的交换结构和输入排队(input queued)的机制。现今对变长数据包的交换方法多数是将数据包切割成定长数据包来交换,效率仍然是比较低的。直接在交叉开关中对变长数据包进行交换,能提高效率,因此研究如何解决数据包乱序问题和分配交叉开关资源的问题就显得非常的迫切了。文中分析了交叉开关机制中多种变长调度算法,介绍了它们各自的优缺点和不同之处,并提出了进一步研究的思路。

Nowadays Crossbar and input queue are widely used as switching fabric of high-performance network switches. For variable-length scheduling, the method of cutting the variable-length packets and encapsulating them into cells is inefficient. Now many variable-length packet scheduling algorithms are based on packet, without cutting packets into cells. And the algorithms about how to handle the packets taking over an input-output resource without interruption and further research on how to make use of the switching sources are urgent. The authors review the research of the variable-length scheduling algorithms for crossbar switch, and analyze these algorithms in detail. Finally research directions and open problems in this area are also discussed.