An Efficient Technique for Dynamic Lightpath Establishment in Survivable Local/Metro WDM Optical Networks

摘要

Providing a reliable and fast connection to a user is one of the challenging issues in a survivable IPover WDM optical network. A dynamic lightpath establishment (DLE) strategy along with a path protection technique may be used to address the issue. In this strategy, a primary lightpath is established when a request for communication from a node comes, and it is released when the communication is over. To protect the primary lightpath, there will also be a backup lightpath. Thus, DLE with path protection is the problem of establishing a pair of primary and backup lightpaths on a call request within a reasonable amount of time. This problem is a variant of the classical Routing and Wavelength Assignment (RWA) problem in the WDM optical network literature. It can be formulated as a combinatorial optimization problem and, in this paper, we have proposed a heuristic search technique, developed based on Best-First Search. We have tested the performance of our technique with respect to the lightpath establishment time (LET) and call blocking probability (CBP) and compared it with the performance of another well-known technique namely Mixed Integer Linear Programming (MILP). We have also studied the performance of our technique with respect to CBP and LET when there are multiple calls to admit. A significant performance gain is noticed in all the above cases.