Next-generation wireless networks (NGN) and internet of Thing (IoT) become two leaders of designing mobile multimedia services. The deployment of these services using heterogeneous wireless networks will be the important factor that leads to profound change in the way that these services are delivered. Also, how these services will be managed is a real challenge. Consequently, Seamless mobility management should be provided to support various services in heterogeneous networks. A SIP-based network appears as a very attractive alternative to mobile multimedia applications. In this paper, we introduce a novel mobility management strategy for mobile SIP networks, in which we develop a seamless handover used mobile SIP scheme called SM-SIP (Seamless Mobility Management for Heterogeneous Wireless Networks for Mobile SIP environment). SM-SIP can significantly reduce the system signaling cost and handover delay, by proactively processing the address allocation and session updates using link layer information of wireless networks. Also, our performance study shows that SM-SIP reduces efficiently packets loss using an anticipated buffering scheme.