Can Elastic Regenerators Reduce Survivability Cost in WDM Optical Networks?

Elastic regenerators can operate at various data-rates according to user demand requirements. This paper studies the impact of these systems on survivability in WDM optical networks and shows how we can benefit from their elasticity characteristics to reduce overall protection cost. Introduction Operators are continually striving to maximize the efficiency of their network infrastructures in order to meet the varying bandwidth demands of their customers. To better fulfill this need, elastic optical networks have recently been proposed [1] using variable rate transceiver/receiver devices, termed as elastic transponders. These devices can be configured dynamically by the control plane to operate at various data-rates according to client's demand requirements [2]. Namely, demands requiring relatively low capacity and long reach can now be transmitted on low bitrate wavelengths, e.g., 10 Gbps (and vice versa). However, long distance lightpath connections typically require regenerators to maintain signal quality. Now since network failures are also a key concern, operators have to develop appropriate recovery mechanisms to maintain service continuity. Here, pre-provisioned protection strategies provide a well-established means for failure recovery, particularly with more efficient shared path protection (SPP) schemes [3]. Along these lines, we propose a novel shared elastic regenerator protection (SERP) strategy to leverage transponder elasticity. Namely, this scheme replaces some fixed regenerators with elastic ones to reduce protection costs and also maintain, as much as possible, existing network infrastructures.