Photon Netw Commun (2014) 28:276–286 DOI 10.1007/s11107-014-0450-6 Power consumption reduction through elastic data rate adaptation in survivable multi-layer optical networks Jordi Perelló · Annalisa Morea · Salvatore Spadaro · Albert Pagès · Sergio Ricciardi · Matthias Gunkel · Gabriel Junyent Received: 20 September 2013 / Accepted: 23 May 2014 / Published online: 10 June 2014 © Springer Science+Business Media New York 2014 Abstract Network survivability requires the provisioning of backup resources in order to protect active traffic against any failure scenario. Backup resources, however, can remain unused most of the time while the network is not in fail- ure condition, inducing high power consumption wastage, if fully powered on. In this paper, we highlight the power consumption wastage of the additional resources for sur- vivability in IP/multi-protocol label switching (MPLS) over dense wavelength division multiplexing multi-layer optical networks. We assume MPLS protection switching as the fail- ure recovery mechanism in the network, a solution interest- ing for current network operators to ensure fast recovery as well as fine-grained recovery treatment per label switched path. Next, we quantitatively show how elastic optical tech- nologies can effectively reduce such a power consumption by dynamically adjusting the data rate of the transponders to the carried amount of traffic. Keywords Multi-layer · DWDM · Survivability · Elastic · Energy efficiency J. Perelló (B ) · S. Spadaro · A. Pagès · S. Ricciardi · G. Junyent Universitat Politècnica de Catalunya (UPC), UPC Campus Nord, Jordi Girona 1-3, 08034 Barcelona, Spain e-mail: perello@ac.upc.edu A. Morea Alcatel-Lucent Bell Labs, Centre de Villarceaux, Nozay, France e-mail: annalisa.morea@alcatel-lucent.com M. Gunkel Deutsche Telekom Fixed-Mobile Engineering Deutschland, Darmstadt, Germany e-mail: GunkelM@telekom.de 1 Introduction IP/multi-protocol label switching (MPLS) over dense wave- length division multiplexing (DWDM) multi-layer optical network architectures are promising solutions to bridge the bandwidth gap between client packet data flows and the ultra- high-capacity lightpaths enabled by recent developments of optical transmission systems and advanced modulation for- mats. That is, transmission equipment at 100 Gb/s is com- mercially available to date, and research efforts are already targeting 400 Gb/s and 1 Tb/s [1]. To efficiently exploit such capacities, multi-layer optical networks allow the grooming of lower speed client flows onto available lightpaths. In this way, intermediate IP/MPLS routers between lightpaths elec- trical termination points can be offloaded compared to pure opaque networks, reducing router capacity requirements, and thus network capital expenditures (CAPEX). With these high capacities, any failure (e.g., fiber cut, transponder or node failure) can lead to catastrophic data losses. These data losses also have associated big economic losses for operators due to the high downtime costs when serving certain kinds of clients. Hence, survivability becomes of paramount importance in the design and operation of multi-layer optical networks. Specifically, network operators seek to equip the minimum additional capacity in nodes and links to make the network survivable against any possible failure scenario, in view of the recovery mechanism that will be employed during network operation. In this work, we focus on IP/MPLS over DWDM multi- layer optical networks, survivable against any single link fail- ure scenario using IP/MPLS protection switching. This solu- tion is interesting for current network operators because: (1) fast label switched path (LSP) recovery below 100 ms can be achieved [2]; (2) recovery is entirely performed at the MPLS layer and there is no need for still immature optical 123