Performance comparisons of restoration techniques in optical burst switching networks

This paper describes restoration techniques for OBS networks. First, we introduce the design issues to be essentially considered, when restoration techniques will be built into OBS networks. Second, considering the design issues, we propose a novel restoration model named “Recover-Then-Reserve,” which can enhance the restoration performance. Third, we develop a simulator using the NS-2 platform to verify the performance of the restoration techniques (path, link, and sub-path) designed by each restoration model (GMPLS-based OBS restoration and our proposal). Performance is evaluated on the following metrics: restoration success rate, restoration time, connection availability, and burst loss probability. The effects of the failure frequency and the number of the restoration attempts on the restoration performance are also investigated. Our experiments show that the proposal can reduce the restoration time by about 25 ms compared to the GMPLS-based OBS restoration model. Also, path restoration technique has better performance than link and sub-path restoration techniques because it has the highest restoration success rate, allowing similar restoration time. Our experiments also show that the more the restoration attempts made and the less the failure frequency becomes, the better the restoration performance obtained.