Switching Techniques, Adaptive Routing And Deadlock Handling In Interconnection Networks

Abstract

This tutorial surveys three key issues in the design of interconnection networks: switching techniques, mechanisms for deadlock handling, and routing algorithms. These three issues are closely related to each other. Switching techniques have a major impact on performance. Several switching techniques will be described, including some recent hybrid techniques, and highlighting the relationship between switching technique and network technology. Routing algorithms determine the path followed by messages from source to destination. Adaptive routing algorithms have the potential to increase link utilization and throughput by avoiding congested regions in the network. However, adaptive routing algorithms are prone to deadlock. The tutorial will present several techniques for deadlock handling in interconnection networks, and their application to the design of adaptive routing algorithms. The talk will describe techniques for deadlock avoidance and recovery, mainly focusing on proposals that allow cyclic dependencies between network resources. Progressive deadlock recovery is emerging as an alternative to deadlock avoidance. In order to make it viable, it is necessary to reduce the frequency of deadlock and to implement an efficient deadlock detection mechanism. Deadlocks will be characterized, presenting mechanisms to reduce the frequency of deadlock, and describing efficient mechanisms for distributed deadlock detection. Several methodologies for the design of adaptive routing algorithms will be described, as well as their application to multicomputer networks and networks of workstations with irregular topologies. Networks of workstations may require long links to connect different nodes and switches. The effect of wire length on performance, and the relationship with flow control mechanisms will be analyzed. Finally, some evaluation results will show the impact of different design parameters on performance.