In this paper we present the design of a global RWA protocol (GRP) consisting of ‘N’ sector networks, each with a centralized management system (CMS) and sectors acts as a node of a distributed system. As per the connection request it uses centralized or hybrid method (centralized and distributed) to identify the primary and backup lightpaths. In addition an extra backup CMS is maintained to takeover if any of the sector CMS fails. It also involves in the data transmission between two sector CMS when the optimal primary lightpath fails. In this protocol lightpaths with least blocking robabilities are used for primary and backup lightpaths. Data is transmitted through the primary lightpath and if primary lightpath fails, the data will be routed through the backup lightpath and the lightpath with next least blocking probability is used as new backup lightpath. Global network overcomes the performance bottleneck of a large network with single CMS. In addition, grooming is also used to improve the blocking probability of connection request
Dr. T. K. Ramesh, Konda, S. Kumar, and R, V. P., “A Global RWA Protocol for WDM networks”, International Journal of Engineering Research and Applications (IJERA), , vol. 1, no. 4, pp. 1685-1689, 2011.