Fault-tolerant reconfiguration of trees and rings in networks

We design two protocols that maintain the nodes of any computer network in a rooted spanning tree and in a unidirectional ring, respectively, in the presence of any finite number of fail-stop failures and repairs of network nodes and communication channels. Our protocols are fully distributed, have optimal time and space complexity, and illustrate two different methods for the design of nonmasking fault-tolerant protocols.<<ETX>>