The paper studies the protection design with link shared for the double-link failures in WDM mesh networks

and proposes a novel heuristic algorithm called TBP (Two Backup Paths) and an improved heuristic algorithm called OBP (One Back Path).The two algorithms both can dynamically adjust the link-cost according to the current state of the network

so that the paths are all the least-cost routes.The paper also investigates the protection switching procedure and calculates the formula of the protection switching time.The simulation results show that

1) the two algorithms both can effectively protect the double-link failures; 2) TBP performs better than OBP; 3) with respect to other algorithms

TBP has the fastest protection switching time.