A Resource Efficient Fast Recovery Strategy for Survivable WDM Networks

Abstract

ABSTRACT

In WDM networks when failure occurs, huge amount of data is lost in a fraction of second. Therefore, the failed connection request must be re-routed through backup route as soon as possible. For achieving fast connection recovery, the primary lightpath is either link or segmented protected. However, the strategies result in inefficient utilization of resources. In this paper, we present a resource efficient parallel signaling-shared path protection (PS-SPP) based strategy for fast connection recovery. In the first step of the strategy, we assign one path disjoint backup lightpath for each primary connection like the traditional shared path protection (SPP) strategy. In the second step, after the detection of failure, both the end nodes of the connection request generate the connection setup messages simultaneously. These connection setup messages exchange the information at the pre-decided intermediate node in the backup route and generate the acknowledgements to the respective end nodes of the connection request. We formulate a model for protection switching time for the proposed strategy and compare it with respect to other strategies such as shared path protection (SPP), shared link protection (SLP), and shared segment protection (SSP). Numerical results obtained by simulating the signaling protocol indicate that for the network topologies of NATIONAL and USNATIONAL, the PS-SPP provides shorter recovery time and uses lesser number of resources than the strategies of SLP and SSP.

Keywords: Wavelength division Multiplexing, Wavelength assignment, Restoration/protection, Survivability