Minimum number of links needed for fault-tolerance in cluster-based network

One of the most difficult problems in network management for large computer networks is to manage a huge amount of network information. The way to overcome the difficulty is to introduce hierarchical control for network management. Additionally, it is said that a locality has a very important role for the design of hierarchical computer networks. The paper proposes a new fault-tolerant topology in a cluster-based network with respect to the locality. The following results are obtained: (1) At least 2n-2 links are needed in the cluster with the fault-tolerant topology, where n is the number of border nodes in the cluster. (2) As far as network connectivity is not losing, updating of routing information at each node can be localized within only the cluster containing failed links