An efficient spare capacity allocation strategy for ATM survivable networks

A variety of restoration algorithms for ATM networks have been investigated previously. This paper proposes an efficient spare capacity allocation strategy for ATM survivable networks, to obtain a better cost-performance feature. Spare capacity on every link of the ATM virtual path (VP) based network is taken as the object of manipulation. Three restraint condition formulas are derived for the establishment of a new working VP (W-VP) or a new backup VP (B-VP), with respect to two parameters: the spare capacity ratio and the spare capacity shared ratio of each link. A hybrid self-healing mechanism with priority restoration is deployed to cooperate with the allocation strategy. Through computer simulation, the impact of these two parameters is studied, and the value of them can be adjusted according to the dynamic load of an ATM network. As a result, the optimum amount and location of spare capacity can be achieved in the ATM network, under the required survivability performance (e.g., restoration ratio, restoration time). Thus the total survivability cost of an ATM network can be minimized