A method and system for providing Quality of Service (QoS) for Session Initiation Protocol (SIP)-based signaling and traffic are disclosed. The method can facilitate the management of Quality of Service in a Session Initiation Protocol-based communication on a cable network by using a built-in Dynamic Service feature to set up, enforce, modify, and tear down Quality of Service enabled service flows for SIP-based signaling and multimedia traffic over the cable system. The system can include a cable modem that is configured to recognize SIP-based signaling and traffic on a CM/Multimedia Terminal Adapter interface. The disclosed method and system can facilitate the provision of SIP-based services utilizing the inherent features of a cable network.