Energy-minimization in IP over WDM optical network for Green Communications
IP over WDM network is a popular network layered architecture for today’s transport network. Using WDM layer’s capacity and IP layer’s intelligence, the combination of the two layers are considered as a cost-effective scheme from the aspects of both network efficiency and operational simplicity. For IP over WDM networks, their power consumption has started to become an interesting research topic.
Recently, a paper “Energy-Minimized Design for IP over WDM Networks” was published in an IEEE/OSA new journal “IEEE/OSA Journal of Optical Communications and Networking, vol. 1, no. 1, June 2009, pp. 176-186.” Viewing the major power consumption by IP routers, the paper targets to minimize the required number IP router ports subject to all the IP traffic is fully supported. The research results indicate that in an IP over WDM network more than 90% power is essentially consumed by the IP routers, and the components in the WDM layer such as transponders and EDFAs actually consume very little energy. Interestingly, the paper also finds that a power-efficient IP over WDM network is likely to be a cost-effective design viewing that the IP router ports are also the most expensive among all the network components.
Due to the major power consumption from IP router, following the above work recently there are also some studies considering sleeping of IP router ports or tuning down the power consumption of IP router port when the data traffic on the port is low. Theoretically these technologies are possible. They are however highly dependent on the standardization of IP routing protocols. Currently, no mature IP technologies can support router port sleeping (though recently Cisco proposed to shut down a router when the internet traffic is low) and different power consumption at different data rates.
