Voice Over IP technology (VoIP) allows people to communicate voice using the Internet as a mean of transmission. VoIP calls between clients using the same Codec consume communication and computational resources from VoIP server. Software-Defined Networking (SDN) has been disseminating the decoupling between control and data plane in network technologies. SDN can be used in order to optimize network traffic and consequently to reduce resources usage. Therefore, this paper aims to present a traffic management approach based on SDN to reduce the use of resources in VoIP services. Scenarios were emulated with and without the use of SDN to assess CPU utilization and bandwidth used in a VoIP server. Experimental results indicate considerable reduction on the consumption of the mentioned resources.