Integrated multi-class routing

In this paper we describe a class of routing algorithms called multi-class algorithms. Multi-class algorithms support multiple classes of routing simultaneously, thereby allowing different applications, and even different messages, to select the most advantageous kind of routing. For example some applications prefer the smaller latency variance of oblivious routing, while others prefer the higher throughputs achieved by adaptive routing. Typical systems provide a single class routing algorithm, but applications benefit from the flexibility of multiple classes. Integrated multi-class routers have two characteristics. First, they provide an integrated algorithm where routing classes share resources such as buffers. Each class is not an independent routing algorithm on an independent network, but rather to reduce costs, each class is implemented by a single algorithm on a shared network. Second, multi-class routers help increase performance by providing routing flexibility and network services which help simplify the network interface or system software. The idea of multi-class routing is perhaps obvious and it has appeared before. Our contribution, however, lies in defining multi-class routers, describing their advantages, providing an appropriate method for evaluating such routers, and by demonstrating their usefulness though examples.