Making inter-domain routing power-aware?

Current network infrastructures exhibit low power efficiency, running network devices at full capacity all the time regardless of traffic demand. Power-aware traffic engineering schemes such as GreenTE improve network energy efficiency by adapting routing paths to traffic demand: when the demand is low, traffic is merged onto fewer links so that idle links can go to sleep, and when the demand is high, more links are being used to satisfy the demand. The effectiveness of this approach, however, depends on path diversity in the network. Existing research work considers only intra-domain part of routing paths, where both ingress point and egress point are fixed. It is unclear whether considering inter-domain path diversity would bring any additional power saving and by how much. In this paper we extend GreenTE to consider inter-domain path and quantify gains in power saving. By making egress point a variable in GreenTE, we are able to utilize more path diversity and get more power saving. Using network topologies from several wide-area networks, our evaluation shows that power saving increases when inter-domain paths are considered, but the amount of additional saving is modest, and depends on various factors.