Provided is a method and system for providing a packet-based multimedia service to a mobile device in a network. The service is defined by a telecommunications standard, such as the 3GPP IP multimedia subsystem (IMS) standard, and the network does not support packet quality of service (QoS) functionality as required by the standard. A communications session embodying the method may be initiated by the mobile device or by the network. The method begins by establishing simultaneous packet signaling and circuit bearer connections with the mobile device. Signaling information for the multimedia service may then be transferred via the packet signaling connection using a session initiation protocol (SIP) or similar protocol. Data for the multimedia service may be transferred via the circuit bearer connection. This enables a feature rich signaling protocol to be used to provide the multimedia service via the network in alignment with the standard, even though the network does not support the required QoS functionality.