We address the problem of routing and wavelength assignment (RWA) considering differentiated reliability (DiR) in WDM mesh networks. The backup resource can be shared by the primary lightpaths. However, both the primary-backup sharing and the different levels of fault tolerance requirement have never been considered together in the literature. In the paper, we consider the dynamic character of the link availability, which is caused by primary-backup sharing. Moreover, the priority of traffic is considered in the paper. The paper focuses on routing under dynamic availability of wavelength resource while the requested reliability of traffic has to be met, using the modified shortest path algorithm. A layered availability model is established based on wavelength layered graph model. Using this model, we propose a new algorithm called dynamic layered availability (DLA) algorithm. We evaluate the performance of the proposed algorithm on the NSFNET.

It is an almost classical problem to develop an efficient broadcast mechanism in multi-hop networks. However, the problem is far from solved though a lot of research till recently has been focused on it. In this letter, we analyze the optimal distribution of forwarding nodes that can doubly cover the network with the minimum transmission overlapped area in a multi-hop wireless network where nodes are ideally distributed. On this basis we propose a simple and effective broadcast method to significantly increase the transmission efficiency and deliverability. In this method, the total number of retransmissions is quite low since each node only needs to select three forwarding nodes, and high deliverability can be achieved for the set of forwarding nodes provide nearly double coverage to the whole network. In addition, the method has excellent scalability in large scale networks and highly dynamic environment.