Hyper-butterfly network: a scalable optimally fault tolerant architecture

Bounded degree networks like deBruijn graphs or wrapped butterfly networks are very important from the VLSI implementation point of view as well as for applications where the computing nodes in the interconnection networks can have only a fixed number of I/O ports. One basic drawback of these networks is that they cannot provide a desired level of fault tolerance because of the bounded degree of the nodes. On the other hand, networks like hypercubes (where the degree of a node grows with the size of a network) can provide the desired fault tolerance but the design of a node becomes problematic for large networks. In their attempt to combine the best of both worlds, authors previously proposed hyper-deBruijn networks that have many additional features of logarithmic diameter, partitionability, embedding, etc. (Ganesan and Pradhan, 1993). However, hyper-deBruijn networks are not regular, are not optimally fault tolerant and the optimal routing is relatively complex. Our aim is to extend these concepts to propose a new family of scalable network graphs that retain all the good features of hyper-deBruijn networks and are regular and maximally fault tolerant. The optimal point to point routing algorithm is very simple