SIP (Session Initiation Protocol, SIP) 為一種協助多媒體會議 (multimedia session) 召開之通訊協定信號標準，因其具有簡單、彈性、具擴充性等優點，今日已被多數國際通訊大廠採用作為建構下一代以 IP 為核心的網路電話以及新一代語音服務之基礎。但當我們想要建置以SIP為基礎的網路電話服務時會碰到一個問題，就是各種廠商的SIP service logic不能互通。換句話說，因為目前並沒有標準來定義及規範SIP伺服器和service logic的溝通方式，所以每家廠商都用自己的方法來溝通，導致各家產品不能互通。以VOCAL的service logic為例，網路管理者必需調整SIP代理伺服器(proxy server)的參數，才能使其service logic可以運作。而如果有一個SIP代理伺服器並沒有提供像VOCAL的參數調整界面，那麼該SIP代理伺服器勢必不能和VOCAL的service logic合作了。這樣一來，服務建置者勢必為每一個廠商的SIP系統量身訂做其service logic，這是一件非常沒有效率的事。所以，本研究將提出一個方法，可以讓service logic輕易的移殖到任何的SIP環境和任何的SIP產品合作。本研究實際實作了一個service logic伺服器，並且以此伺服器例舉出三個實際的運作例子來証明本研究的方法可行。並且，本研究還做了一系列的效能及其它因子的評估來顯示本研究的方法不僅可以使service logic有可移殖性，且可以在很多方面運作得跟其它方法一樣好。 Session Initiation Protocol (SIP) is a kind of signaling protocol in Internet. SIP is simpler than other signaling protocols, such as H.323. Creating some telephony services in SIP is easier than in PSTN. So, we pick up SIP to build the Internet telephone network. When we start to build the Internet telephone network environment, we meet a problem “the service logic is lack of portability” in respect of telephony services creation. Taking the VOCAL Feature Server mechanism as an example, we must configure the SIP server to tell it where the service logic is. If other SIP servers without the ability of configuration, they can not cooperate with the service logic of VOCAL. So, we propose an approach to solve this problem in this thesis. The core of this approach is that we make all SIP transactions (that is related with end users in service domain) pass through the service logic server automatically. It is unnecessary to configure the SIP servers in our approach. So, whether the SIP server with the ability to configure or not, our service logic can work with it. In short, our service logic has the portability. In this thesis, we also implement three real application examples using our approach to demonstrate our proposal. Finally, we make some comparisons and evaluations between our approach and others. This evaluation shows that our approach can run as good as others in many aspects, and our approach has the biggest advantage- portability.
