This paper proposes a service-oriented network architecture for next-generation power grids, i.e., smart grids. The proposed architecture includes Ethernet passive optical network (EPON)-based optical access systems and service-oriented routers (SoRs). The SoR function is embedded into any communication nodes for capturing, filtering, storing, selecting, calculating, and redirecting requests in network traffic. The maximum throughput of the developed SoR is 1.12 Gbps, and the size of its packet buffer is approximately 100 MB. To confirm the feasibility of the proposed service-oriented architecture for smart grid communications, the performance of a power grid model is evaluated using MATLAB/Simulink and SimPowerSystems Toolbox.