現今的MIP與HMIP在Handoff完成後才重新送出連線的請求，會花費不少時間，對於Time sensitive的訊務來說是一個相當不利的因素。在深入研究過SIP這一個新興的通訊協定之後，對於進行中的session，SIP提供了同一個session的封包送達至新的位址，以達成在應用層上的無縫接取服務。利用SIP可以將session重導的能力，將之導入無線網路的通訊裡，讓重新連線在handoff的過程裡同時發生，進而大幅縮短session因handoff的程序而中斷的時間。
本論文將在使用SIP信令系統於異質性無線網路架構中，分析不同的伺服器配置方式對SIP信令的傳遞會造成何種影響。進而找出能夠使信令傳遞延遲時間最小的架構，應用在異質性無線網路中，達成快速建立連線並減少衝擊以維持會談服務品質的目的。

In current application, the request of MIP (Mobile IP) and HMIP (Hierarchical Mobile IP) only be sent after handoff will take lots of time, and it is a quite unfavorable factor to time sensitive frame. Investigating this new communication protocol for SIP proves that while a session sending and SIP will offer a package of the same session to the new address to seamless serve in time in the application layer. Applying the ability of SIP (resending the session) to wireless communication network will lessen the connecting time which causes re-connecting when handoff happened.
In this research, we will estimate the performance of SIP in different server and the influence on session passing while setting changed. Our efforts are to find the best solution of minimun delay time and reduce the impact on establishing multimedia session to achieve the required QoS (Quality of Service).

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