Energy Efficient and Bandwidth Guaranteed Design for Optical Network With Mixed Sleep-Enabled and Non-Sleep-Enabled Router Cards

Abstract

With rapidly growing Internet traffic, energy efficient operation of IP over WDM networks with sleep enabled routers is of increasing interest. However, for network security and to provide guaranteed communications, it would still be desirable to ensure that a certain fraction of the bandwidth is assured through routers which cannot be put to sleep using software control. This paper presents an energy-minimized IP over WDM network using a mixture of sleep-enabled and non-sleep-enabled router cards where a certain percentage of the network bandwidth is guaranteed to the offered traffic. Such a mixed configuration is also motivated by the fact that there will always be some traffic demand between each node pair at any time even though the traffic between node pairs may fluctuate to very low levels. This implies a need for some non-sleeping router cards at any time. Another motivation for this mixed configuration is because in the course of migration from today's networks with non-sleep-enabled cards to future networks with sleep-enabled cards, the non-sleep-enabled network devices will not be quickly abandoned but will be gradually replaced. This also causes a network situation with the mixed router card types. To design an IP over WDM network where both sleep-enabled and non-sleep-enabled router cards are used, we propose a mixed integer linear programming (MILP) model which jointly minimizes the energy consumption of all the router cards while guaranteeing a secured fractional bandwidth for all the node pairs. Modified MILPs with subsequent port-channel association are also proposed along with efficient heuristic algorithms which perform almost as well as the joint MILP approaches. The performance of these approaches is studied through simulations on a wide variety of networks.