Wireless Broadband Technologies: Ip Based Wimax Architecture/Network Model
iv. Connectivity service network (CSN): The CSN provides connectivity to the Internet, ASP, other public networks, and corporate networks. The CSN is owned by the NSP (Network Service Provider) and includes AAA servers that support authentication for the devices, users, and specific services. Additional functions od CSN are:
CSN provides per user policy management of QoS and security
CSN is also responsible for IP address management
Support for roaming between different NSPs
Location management between ASNs
Mobility and roaming between ASNs.
v. Home Agent (HA): The Home Agent within the WiMAX network is located within the CSN. With Mobile-IP forming a key element within WiMAX technology, the Home Agent works in conjunction with a
"Foreign Agent", such as the ASN Gateway, to provide an efficient end-to-end Mobile IP solution. The Home Agent serves as an anchor point for subscribers, providing secure roaming with QOS capabilities.
vi. Authentication, Authorization and Accounting Server (AAA): As with any communications or wireless system requiring subscription services, an Authentication, Authorization and Accounting server is used. This is included within the CSN.
The WiMAX architecture framework allows for the flexible decomposition/combination of functional entities when building the physical entites.
For example, the ASN may be decomposed into base station transceivers (BST), base station controllers (BSC), and an ASNGW analogous to the GSM model of BTS, BSC, and Serving GPRS Support Node (SGSN).