Spare channel assignment for restoration in fault-tolerant loop network

The authors consider a computer network, which provides working channels and spare channels for each link, and restores working channels on a faulty link by spare channels on other links. For such a fault-tolerant network, spare channels must be carefully assigned on each link beforehand. However, it is said that finding an efficient assignment for a general network is time consuming, since it is closely related to a linear programming problem including a large number of inequalities. The authors discuss spare channel assignment for a doubly-looped network. At first, by utilizing the characteristics of such a network, they transform a set of 2n(n-1) inequalities to be solved into n groups of rather simple inequalities, where n is the number of nodes in the network. Then they present an algorithm which finds a spare channel assignment efficiently for a doubly-looped network