隨著近幾年行動通訊技術逐漸成熟，行動科技不只是電話通訊，他是一項結合語音、視訊與資料傳輸的技術。而為了將這些技術服務進行標準化，國際合作組織3GPP設計了IP多媒體子系統(IP Multimedia Subsystem，簡稱IMS)架構。IMS是由3GPP所設計，為了提供行動通訊用戶多媒體服務；近幾年IMS已經成為一種行動通訊、無線網路與寬頻多媒體服務之整合架構，在不久的將來，IMS將是3G服務、有線電視、下一代通訊網路之核心。隨著第三代行動通訊用戶(3G Users)的數量提升，IMS服務與客戶端軟體將是未來一項重要的需求，使用者需要一套符合標準之軟體來存取各種IMS服務，例如語音通話、視訊通話、傳送即時訊息、傳送簡訊與多媒體訊息以及透過IMS管理與交換使用者個人資料。 本篇論文中描述以使用開放原始碼之程式庫OPAL與PTLib，建立IMS系統之客戶端軟體經驗，該函式庫具備跨平台之能力，能應用於Win32與Linux系統。其中功能項目著重於使用者資訊與即時訊息功能。本篇論文將以Win32系統為例，建立一符合標準之客戶端程式。 As the mobile communication become mature in recent years, mobile technology is not only using in make phone call. It is a technology for Voice, Data and Video. In order to standardize different service and provide more multimedia services, 3rd Generation Partnership Project (3GPP) cite{ref:3gpp} design the IMS architecture. It is a framework to deliver Internet Protocol multimedia to mobile users. In recent years, IMS becomes an integration framework for mobile communication, wireless network and broadband multimedia service. In the nearly future, it will be the core component within 3G, cable TV and next generation fixed telecoms networks. As 3rd Generation mobile users grow up, IMS service and client software requirement become important in future. Users need a client software to access the IMS services. Such as voice call, video call, sending instant messages, access SMS and MMS and using presence function to exchange person profile. This paper explains experiences in using open source library to build IMS client software. Client function focuses on library using, Presence function and Instant Message design.
