A novel adaptive operation of multi-line rate transponder for dedicated protection in WDM network

As the increasingly large amount of traffic are carried out by WDM networks and the era of information society has been clearly shaped, any network failure would cause massive impact. Operators have been therefore paying growing attention to resilience issues and indeed, guaranteeing survivability has become integral part of network design process. Among protection schemes, dedicated one stands out in terms of efficient recovery speed, ease of operation and thus, being widely deployed in practice. The significant progress in flexible optics are inspiring new opportunities in dimensioning optical network with dedicated protection. In this context, the paper investigates the use of multi-line rate (MLR) transponder having two bit-rate options by switching the modulation format for dedicated protection purpose. A novel adaptive operation of MLR is proposed based on the protection-aware configuration. The protection-aware scheme exploits MLR transponders at lower bit-rate for working mode and adaptively tunes them to higher rate to handle temporary protection traffic in case of failure. We formulate the routing and flow allocation in opaque WDM network design with dedicated protection as mixed integer linear programming and propose two transponder allocation algorithms based on protection-aware operation. The benefits of our new protection proposals compared to traditional approach are quantified over extensive simulations on diverse network topologies and random traffic matrices. Encouraging results are observed with a saving of more than 30% number of transponder and promising cost and power consumption gain could be achieved in a wide range of MLR cost and power consumption assumption.