Hypercube connected rings: a scalable and fault-tolerant logical topology for optical networks

Abstract

A new, fault-tolerant, scalable, and modular virtual topology for lightwave networks employing wavelength division multiplexing is proposed. The proposed architecture is based on a hypercube connected ring structure that enjoys the rich topological properties of a hypercube, but it also overcomes one of its drawbacks. In a hypercube, the nodal degree increases with the number of nodes. Hence, the per-node cost of the network increases as the network size grows. However, in a hypercube connected ring network (HCRNet) the nodal degree is small and it remains constant, independent of the network population. A HCRNet, like a hypercube, is perfectly symmetric in the sense that the average internodal distance in an N-node HCRNet is the same from any source node. Its average internodal distance is in the order of logN and it is comparable to other regular structures such as the Trous and ShuffleNet. The HCRNet is based on the Cube Connected Cycle (CCC) interconnection pattern proposed for multiprocessor architectures. However, the HCRNet improves on CCC by rearranging its hypercube links, which results in a significantly lower average internodal distance. In this paper we present the structural properties of HCRNet, and address the issues of scalability, and fast routing in complete as well as incomplete HCRNet.