Spare capacity allocation design schemes in self-healing ATM networks

In an ATM mesh network, the failure of a network element (e.g. fiber links or cross-connects) may lead to large data losses. Determining where to place spare capacity in the network and how much spare capacity must be allocated to guarantee seamless communications services survivable to network element failure is therefore a key concern. This problem, referred to as the spare capacity allocation (SCA) problem in mesh-type networks, has been extensively studied and the focus in almost all solution approaches has been to determine the optimal SCA assignment and backup virtual paths allocation for all traffic flows. However, there has been almost no study on the effect the choice of backup virtual paths (which determines our so called SCA design schemes) might have on the optimized SCA. This paper compares four SCA design schemes quantitatively in terms of the spare capacity requirements. The comparison is based on spare optimization, single link failure or single node failure scenarios, and 100% restoration. As expected, it is found that the "joint selection of the working virtual paths and backup virtual paths among all possible paths" can significantly reduce the spare capacity cost compared to other studied options.