W-CSCF之一段式認證機制設計

Abstract

全球行動電信系統(Universal Mobile Telecommunication System，UMTS) 透過網際網路通訊協定多媒體子系統(IP Multimedia Subsystem，IMS) 來達成支援多媒體服務。而在網際網路通訊協定多媒體子系統中，是由呼叫通話控制功能(Call Session Control Function，CSCF) 來提供多媒體服務。WGSN整合了SGSN和GGSN的功能，並且在分封數據網路和無線網路結點之間扮演閘道的角色。除此之外，WGSN提供了連接到GPRS網路的存取機制。 於本論文中，我們提出無線區域網路之呼叫通話控制功能(WLAN-based CSCF，W-CSCF)這個元件，使得在WGSN網路上的無線用戶端可以取得IMS的服務。W-CSCF整合了Interrogating CSCF (I-CSCF) 和 Serving CSCF (S-CSCF)的功能，並且負責提供服務控制和通話控制的功能。當使用者欲取得IMS服務之前，必需在GPRS和IMS兩個網路上通過認證機制。針對無線用戶端透過WGSN存取IMS服務，我們提出了一段式認證機制 (One-Pass Authentication mechanism)。一段式認證機制也是需要執行GPRS的認證機制，但是簡化了IMS的認證機制。

Universal Mobile Telecommunications System (UMTS) supports multimedia services through IP Multimedia Subsystem (IMS). In IMS, multimedia services are setup and controlled by the Call Session Control Function (CSCF). The WLAN-based GPRS Support Node (WGSN) integrates both Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN) functionalities and acts as a gateway between the Packet Data Network (PDN) and the WLAN node. Besides, the WGSN node provides an access mechanism to a GRPS network. In this thesis, we propose a component, WLAN-based Call Session Control Function (W-CSCF), to provide WLAN users in a WGSN network to access the IMS services. The W-CSCF node integrates both the I-CSCF and S-CSCF functionalities and is responsible for the service control and call control. Authentication procedure is performed at both the GPRS and the IMS networks before an MS can access the IMS services. We present a One-Pass Authentication mechanism for WLAN users to access the IMS services through a WGSN. One-Pass Authentication performs the GPRS authentication but simplifies the IMS authentication.