Current IP mobile backbone networks exhibit poor power efficiency, running network devices at full capacity all the time regardless of the traffic demand and distribution over the network. Network operators usually build networks with redundant and overprovisioned links resulting in low link utilization during most of the time. While these redundant links and bandwidth greatly increase the network reliability, they also greatly reduce the network’s energy efficiency as all the network devices are powered ON at full capacity but highly under-utilized most of the time. Most research on router power management treat routers as isolated devices. An alternate approach is to facilitate power management at network level by routing traffic through different paths to adjust the workload on individual routers or links. In this thesis work focuses on intra-domain traffic engineering mechanism, EE-TE formulated based on MCF model and it is solved using the powerful optimization engine CPLEX. The EE-TE model maximizes the total power saving of routers in a network by finding energy efficient routing paths for each OD pair and also shows how to split the traffic on a chosen path depending on the actual traffic demand measured in the network. EE-TE maximizes the number of links that can be put into sleep under given performance constraints such as link utilization and traffic split ratio. Using random network topologies and traffic demand profiles, the evaluation shows that EE-TE can reduce line-cards’ power consumption by 20% to 40% under constraints that the maximum link utilization is below 50% for IP-based mobile backbone networks.