The Fork-Join Terabit per Second Router

互联网同时面临着两个问题：我们需要更快的交换/路由基础设施，我们需要引入有保证的服务质量（QoS）。作为一个社区，我们对每个人都有建议：我们可以通过使用输入排队的交叉开关来提高路由器的速度，而不是使用共享内存系统；我们可以使用基于加权公平队列的分组调度来引入QoS。但我们不知道如何同时做到这两点。到目前为止，这两种解决方案一直是相互排斥的——基于wfq的调度算法的所有工作都要求交换机/路由器使用输出队列或集中式共享内存。Fork-Join路由器旨在解决这两个问题。该路由器是一种高性能、可扩展、容错系统，设计为每秒运行数太比特，同时提供精确的服务质量支持。路由器是高度并行的，由多个相同的独立操作平面组成。当它们到达时，属于同一流的所有数据包都被定向（分叉）到路由器的同一平面进行处理。在离开之前，流被重新合并（加入），以维持系统中每个流的QoS。在构建fork-join路由器之前（作为原型，或者在工业中作为商业产品）必须回答一些重要的问题：如何实现fork、join和switch调度功能？我们的工作重点是回答这些问题。

The Internet is facing two problems simultaneously: we need a fasterswitching/routing infrastructure, and we need to introduce guaranteedqualities of service (QoS). As a community, we have proposals for each: wecan make the routers faster by using input-queued crossbar switches,instead of shared memory systems; and we can introduce QoS using WFQ-based(weighted fair queueing) packet scheduling. But we don't know how to doboth at the same time. Until now, the two solutions have been mutuallyexclusive - all of the work on WFQ-based scheduling algorithms has requiredthat switches/routers use output-queueing, or centralized shared memory.The Fork-Join Router is designed to address both problems. The router is avery high performance, scalable, fault-tolerant system designed to operateat multi-terabits per second, yet provide exact support for qualities ofservice. The router is highly parallel, and is composed of multiple,identical, independently operating planes. When they arrive, all of thepackets belonging to the same flow are directed (forked) to the same planeof the router for processing. Prior to departure, the flows are remerged(joined) soas to maintain the QoS of each flow through the system.Before a fork-join router can be built (as a prototype, or in industry as acommercial product) some significant questions must be answered: How canthe fork, join and switch scheduling functions be implemented? Our workfocusses on answering these problems.