On cost-based routing in connection-oriented high-speed networks

Not only does cost-based routing achieve a higher throughput, it also removes the instability problem inherent in fixed-path routing networks with alternate paths. In the paper we evaluate the performance of two cost-based routing schemes: one centralized and one distributed. The latter has a much lower complexity than the former. Although the distributed version does not always use the least-cost path, our results indicate the performance of both schemes are about the same. We also compare them with least-loaded routing to demonstrate the ability of cost-based routing to stabilize the network performance even under an over-loaded condition. But to make cost-based routing a viable option for a high-speed network, vie must. find a way to compute the cost function. Recently a theory based on the concept of quantization was developed. It can significantly reduce the complexity of cost computation. With this problem solved, cost-based routing becomes a serious contending routing algorithm for a high-speed multirate network. The results in the paper demonstrate that the performance degradation caused by quantizing the cost function is insignificant.