Anna V. Manolova

Green-aware routing in GMPLS networks

The increasing amount of traffic in the Internet has been accommodated by the exponential growth of bandwidth provided by the optical networks technologies. However, such a growth has been also accompanied by an increase in the energy consumption and the concomitant green house gases (GHG) emissions. Despite the efforts for improving energy efficiency in silicon technologies and network designs, the large energy consumption still poses challenges for the future development of Internet. In this paper, we propose an extension of the Open Shortest Path First - Traffic Engineering (OSPF-TE) protocol and a green-aware routing and wavelength assignment (RWA) algorithm for minimizing the GHG emissions by routing connection requests through green network elements (NE). The network behavior and the performance of the algorithm are analyzed through simulations under different scenarios, and results show that it is possible to reduce GHGs emissions at the expense of an increase in the path length, and, in some cases, in the blocking probability. The trade-off between emissions and performance is studied. To the authors knowledge, this is the first work that provides a detailed study of a green-aware OSPF protocol.

OSPF-TE extensions for green routing in optical networks

This paper proposes extensions to the OSPF-TE protocol to enable green routing in GMPLS-controlled optical networks. Simulation results show a remarkable reduction in CO2 emissions by preferring network elements powered by green energy sources in the connection routing.

Eco-sustainable routing in optical networks

It is quite easy to foresee that in the next years, the future generation ultra-high speed network infrastructures and equipments will be no longer constrained only by their pure transport capacity, but also by their energy consumption costs and environmental effects. In particular, large network infrastructures are now widely recognized to play a fundamental role in the emission of greenhouse gases in the atmosphere, significantly affecting the environmental sustainability of new evolutions in network architectures as well as technological developments in communication devices. In this paper, a novel eco-sustainable routing and wavelength assignment algorithm, based on shortest path routing with an adaptive link weighting function relying on an extension of the OSPF-TE protocol to convey carbon footprint information, has been proposed to decrease the network ecological impact while balancing the traffic load and maintaining acceptable connection-blocking rate. The trade-off between load balancing and carbon footprint is also analyzed to evaluate the effectiveness of the proposed strategy within the context of a real world network.

Shared Path Protection in GMPLS networks with limited wavelength conversion capability

Sharing of protection resources is a cost-effective solution to guarantee survivability against failures. In wavelength-switched optical networks (WSON), in addition to sharing the wavelengths resources, wavelength converters (WCs) can also be shared by different optical connections, or lightpaths. This paper considers the problem of ensuring 100% survivability against single-link failures in a GMPLS-enabled optical network. RSVP-TE signalling protocol extensions for wavelength sharing under Shared Path Protection have been recently proposed for networks with wavelength continuity constraint. In this work, the performance of the proposed extensions is evaluated in a network with limited wavelength conversion. Furthermore, new extensions are proposed for an efficient WC sharing and their impact on the resource sharing is evaluated by simulations. Results indicate a trade-off between providing high wavelength sharing (i.e., low wavelength overbuild) and good WC sharing.

Wavelengths and Regenerators Sharing in GMPLS-Controlled WSONs

In Wavelength Switched Optical Networks (WSONs), sharing of protection wavelengths is an attractive strategy to increase survivability against failures. However, to guarantee an acceptable quality of transmission (QoT), both working and protection paths may need to undergo optical-electrical-optical (OEO) regeneration. With this aim, the placement of a limited number of regenerators is a cost-effective solution to guarantee QoT. In this paper, the concept of sharing the protection resources is extended to regenerators. Moreover, shared regenerators can be exploited for ensuring QoT as well as for providing wavelength conversion. The main objective of this paper is the study of different strategies for the selection of regenerators and wavelengths in WSON with a GMPLS-based distributed control plane. Simulation results show a trade-off between the strategies achieving a high wavelength sharing and those achieving a high regenerator sharing.

Signaling-Based Joint Selection of Wavelengths and Regenerator Points in GMPLS-Controlled WSONs

In wavelength switched optical networks (WSON), quality of transmission (QoT) can be guaranteed by regenerating the optical signal in intermediate nodes. Regeneration can also offer wavelength conversion. When only few regenerators are placed in the WSON, the main issue is to optimally select the nodes where regeneration and wavelength conversion should take place. This paper proposes a distributed strategy for joint selection of wavelengths and regeneration locations (points) in a dynamic WSON with GMPLS control plane. To support the strategy, extensions to the RSVP-TE protocol are proposed. Simulation results show a significant improvement of the connection blocking and fairness, as well as a reduced amount of used regenerators in the network compared with existing strategies, which are based on disjoint and non- distributed resource selection.

Restoration in multi-domain GMPLS-based networks

In this paper, we evaluate the efficiency of using restoration mechanisms in a dynamic multi-domain GMPLS network. Major challenges and solutions are introduced and two well-known restoration schemes (End-to-End and Local-to-End) are evaluated. Additionally, new restoration mechanisms are introduced: one based on the position of a failed link, called Location-Based, and another based on minimizing the additional resources consumed during restoration, called Shortest-New. A complete set of simulations in different network scenarios show where each mechanism is more efficient in terms, such as, resource overbuild or recovery delay.

Performance comparison of multi-domain routing schemes in GMPLS networks with BGP

We compare an enhancement of the BGP protocol for TE support in GMPLS networks with a simple TE extension of BGP in terms of signaling overhead and connection blocking ratio. Our results show increased performance of the enhanced BGP.

Restoration in GMPLS-based wavelength switched optical networks with limited wavelength converters

This paper exploits wavelength converters in GMPLS-based wavelength switched optical networks to reduce resource contentions during lightpath restoration. Reduction of the restoration blocking is achieved thanks to wavelength conversion and an intelligent wavelength selection strategy.

Wavelength converter placement in optical networks with dynamic traffic

We evaluate the connection provisioning performance of GMPLS-controlled wavelength routed networks under dynamic traffic load and using three different wavelength converter placement heuristics. Results show that a simple uniform placement heuristic matches the performance of complex heuristics under dynamic traffic assumptions.