Switching vs Routing within Multidimensional Torus Interconnect

Torus topology is widespread recently in supercomputer domain as well as in the domain of networks on chip. It represents an ideal communication structure with shortest distance and multitude of alternative shortest paths between a pair of nodes. An overview of routing algorithms within multidimensional torus interconnect is presented including processing of global information and adaptation for load balancing to avoid congestions. The paper concentrates on simple and powerful local packet forwarding (switching) rules which does not require tables of addresses (routes) and can be implemented as microprogram code of switching nodes that increases considerably the network performance, security, and QoS providing also quasi-optimal load balancing. To study and compare the packet forwarding rules, an ad-hoc simulator of torus interconnect ts is implemented in C language to provide high performance and possibility of simulation on prolonged intervals of time. The simulation results acknowledge the mentioned advantages of using local packet forwarding rules.