Multi-period logical topology design for IP-over-WDM network with mixed line rates

Improving network energy efficiency has been a challenging issue for the development of networks. Considering the pattern and variation of network traffic, some network components can be turned off during the periods with light load to save energy. However, turning off/on network devices adapting to traffic load may result in the reconfiguration of logical topology in optical wavelength routed networks. On the other hand, the traffic in future network is expected to show high heterogeneity on bandwidth requirement. With flexibility on network provisioning, Mixed Line Rate (MLR) scheme is proposed as a promising candidate to support heterogeneous traffic demand. In this paper, we study the logical topology design of IP-over-WDM network with mixed line rates. We formulate the multi-period logical topology design problem as a mixed integer linear programming (MILP) model with the objective to minimize the overall network power consumption and the reconfiguration overhead between consecutive time periods. Then the proposed model is evaluated and compared with conventional schemes.