Green optical backbone networks: virtual topology adaptation using a page rank‐based rating system

Abstract

An energy-aware virtual topology rating system is proposed in this work, which can be utilized as a tool during the virtual topology reconfiguration procedure in an optical backbone network in order to reduce its energy consumption. It is well known that maintaining a static virtual topology in Internet Protocol (IP)-over-Wavelength Division Multiplexing (WDM) networks is not energy-efficient. To that end, virtual topology adaptation algorithms have been developed to adjust the virtual topology to the constantly fluctuating traffic load. While these algorithms achieve significant energy savings, further reduction on the total network energy consumption can be achieved through the proposed rating system. The proposed rating system is a modified version of the page rank algorithm, which ranks websites in the Internet based on their importance. The proposed rating system attributes ratings to lightpaths, which indicate the relative significance of a lightpath in the virtual topology in terms of energy consumption. The rating can be used during the routing procedure as an energy efficiency indicator, in order to increase the number of lightpaths that are deactivated from the reconfiguration mechanism and increase the utilization per lightpath. The proposed reconfiguration scheme (page rank-based virtual topology reconfiguration) achieves up to 12% additional energy savings in comparison to an existing virtual topology reconfiguration algorithm at the cost of slightly increased average hop distance.

Operation algorithms for energy-efficient backbone networks

“…As a result, PR-VTR achieves up to 12% energy savings in comparison to Simple VTR for a standard set of thresholds {70, 20}, while it manages 5% energy savings in the other cases. PR-VTR has been published in [203].…”

“…In [203], a novel energy-aware routing algorithm was proposed that aims to reduce the network power consumption without deteriorating the network performance.…”

“…The lightpath evaluation is based on the principle that lightpaths which already serve more traffic flows are more valuable, while low loaded lightpaths do not justify the maintenance energy cost and should be deactivated. The work featured in this chapter has been published in [203].…”

Energy efficient optical backbone networks

“…By deactivating underutilized lightpaths and carrying their load through alternative lightpaths, the reconfiguration algorithm manages to save significant amounts of energy. The algorithm proposed in [41] also employs a threshold mechanism to monitor the state of the virtual topology. Based on this monitoring mechanism the virtual topology reacts and adjusts to dynamic traffic demands in order to reduce the operational energy cost of the network.…”