Reliable Loop Topologies for Large Local Computer Networks

Single-loop networks tend to become unreliable when the number of nodes in the network becomes large. Reliability can be improved using double loops. In this paper a highly reliable and efficient double-loop network architecture is proposed and analyzed. This network is based on forward loop backward hop topology, with a loop in the forward direction connecting all the neighboring nodes, and a backward loop connecting nodes that are separated by a distance ⌊√N⌋where N is the number of nodes in the network. It is shown that this topology is optimal, among this class of double-loop networks, in terms of diameter, average hop distance, processing overhead, delay, throughput, and reliability. The paper includes derivation of closed form expressions for diameter and average hop distance, throughput, and number of distinct routes between two farthest nodes. For fault-tolerance study, the effect of node and link failures on the performance of the network is analyzed. A simple distributed routing algorithm for reliable loop network operation is also presented.