The recent trend is to realize such an integrated communication network that can meet demands of multiple services like voice, video, data transmission etc. Mobility management in such integrated networks has become an important area of research especially in this fast world. This paper introduces a mobility management scheme for an integrated network in context of 3rd generation mobile communication system. The scheme is built and extended from mobile IP, combined with the advantages of other networks in the aspect of mobility management. The proposed scheme reduces the amount of signaling traffic, allows increasing number of users without creating a bottleneck. It supports high scalability and improves network performance.