A communications system is described for enforcing a service level agreement for a specified customer on a network. The communications system includes a router to receive at least one packet containing data. A management system is in communication with the router, where the management system provides access control commands to the router for the specified customer based upon an agreed upon codec and an agreed upon packet length. A detection system is in communication with the router. The detection system extracts a codec information and a packet length information from the packet. If the codec matches the agreed upon codec and the packet length matches the agreed upon packet length, then the packet is allowed to proceed. Otherwise the packet is dropped from the network.