Fast Spanning Tree Reconnection (FSTR) is a newly proposed restoration method by us to handle single link failures in Metro Ethernet networks. Compared with other methods existing in the literature, FSTR has the advantages of lower signalling overhead, faster recovery and lesser rerouted traffic. In this work, we propose to use partial spatial protection (PSP) mechanism to provision differentiated reliability (DiR) and, as a result, to decrease the blocking probability of traffic requests in FSTR- based Metro Ethernet networks. In PSP, a traffic request is protected using backup bandwidth against the failure of only a subset of the links on its route. We develop a mixed integer linear programming (MILP) model for PSP to minimize the bandwidth reserved by an incoming traffic request while satisfying the protection grade required by the traffic request. The numerical results demonstrate that the proposed solution can reduce the blocking probability of traffic requests by up to 83% in a 4×4 grid network, compared to that in full protection.

Optical burst switching (OBS) is a promising technique for wavelength division multiplexing (WDM) networks. In practice, wavelength converters (WCs) are either absent or only sparsely deployed in WDM networks due to economic and technical limitations. Thus, wavelength assignment is expected to be an important component of OBS networks. In this paper, an offline wavelength assignment scheme in OBS networks without wavelength conversion capability is proposed. The key idea of the scheme is to decide the wavelength searching order of each traffic connection at edge nodes according to the wavelength priorities determined by the calculated burst loss probabilities on different wavelengths. Simulation results indicate that the proposed scheme can reduce the network-wide burst loss probability significantly compared with other schemes. It is also illustrated that the performance of the proposed scheme can be further enhanced by a larger number of wavelengths per link and a reasonable delay bound at edge nodes.