On Finding maximally redundant trees in strictly linear time

Redundant trees are commonly used for protection and restoration in communications networks. Zhang et al. presented a linear time algorithm to compute node-redundant trees in 2-node-connected networks, which has become widely cited in the literature. In this paper, we show that it is difficult to implement this algorithm providing both correctness and linear complexity at the same time. Therefore, we present a revised algorithm with strict linear time complexity. Moreover, we generalize the concept of node-redundant trees from 2-node-connected networks to arbitrary topologies, a crucial development since real networks can not always satisfy 2-connectedness, especially after a failure.