Multi-domain grooming in power source aware networks

Traffic grooming is necessary for the efficient use of optical networks. It generally requires a signal-conversion from the optical to the electrical domain and back. Planners have some freedom in selecting the location where this energy-intensive process takes place. A subset of nodes in a network may be powered by renewable energy sources. Those green nodes cause lower green house gas (GHG) emissions than others. We suggest to choose these sites for grooming. We propose a model for GHG emissions caused by network operations. Depending on the level of penetration of renewable sources in the power supplies across the network, emissions can be reduced significantly. Potentially spanning different network domains, we introduce a hierarchical grooming approach to collect and multiplex traffic at those green nodes, groom it there and therefore save emissions. We evaluate the emission model and the hierarchical approaches´ performance. Further, we apply them to various network/demand scenarios in an effort to identify favorable conditions for this scheme. We find that by relaxing energy-efficiency requirements in green nodes, and being more stringent in black nodes, we can reduce overall network emissions. The hierarchical approach is scalable and efficiently applicable to operating and future networks.