SIP-Based User-Oriented Handoff Control for Video Phone

The goal of the research is to reestablish the session quickly for moving users according to a suit of user-oriented seamless handoff control framework ( USHC ) the prior researches mentioned. Furthermore, the model about making use of SIP with offer/answer, which is rested on two methods consisting of the REFER with Quality Negotiation and RS-based 3PCC session mobility controls adopted for inter-domain handoff and intra-domain handoff respectively, is to provide the service of video transmitting and defines the detail SDP exchanged during handoff. Besides, we analyzed the situation that the underflow and overflow case in the procedure of RS-based 3PCC and REFER with Quality Negotiation respectively caused by network delay during the procedure of handoff and set up two kinds of thresholds to detect the problem about network delay. In the conclusion, we state the future work about audio/video synchronization to verify whether the theorem is correct or not.