Cut-through switching promises low latency delivery and has been used in new generation switches, especially in high speed networks demanding low communication latency. The interconnection of cut-through switches provides an excellent network platform for high speed local area networks (LANs). For cost and performance reasons. Irregular topologies should be supported in such a switch-based network. Switched irregular networks are truly incrementally scalable and have potential to be reconfigured to adapt to the dynamics of network traffic conditions. Due to the arbitrary topologies of networks, it is critical to develop an efficient deadlock-free routing algorithm. A novel deadlock-free adaptive routing algorithm called adaptive-trail routing is proposed to allow irregular interconnection of cut-through switches. The adaptive routing algorithm is based on two unidirectional adaptive trails constructed from two opposite unidirectional Eulerian trails. Some heuristics are suggested in terms of the selection of Eulerian trails, the avoidance of long routing paths, and the degree of adaptivity. Extensive simulation experiments are conducted to evaluate the performance of the proposed and two other routing algorithms under different topologies and traffic workloads.

Switch-based networks have received much attention in local area networks (LANs) due to their higher network bandwidth and greater interconnect scalability than shared-medium networks. While arbitrary topologies are allowed to provide the needed flexibility and scalability, the design of an appropriate network topology is a challenging issue. In this paper, we discuss design considerations and propose efficient methods for network planning and tuning in switch-based LANs. The idea of block design is applied to initial topology design. For network tuning, a systematic method is proposed to reduce message latency and increase network throughput. Simulations are conducted to demonstrate the performance improvement by applying our method.