Network selection for public WLANs

Abstract

Wireless LAN (WLAN) Access Networks are being deployed in a variety of public places. With an ever-increasing number of WLAN users, public area hotspot locations, such as airports, are becoming prime real estate for operators competing to provide this service. Since operators cannot install their own WLAN infrastructure at all locations where subscribers may want to use the service, roaming agreements that allow customers to access WLAN service offered by roaming partner operators are ess ential. The presence of several operators that can provide WLAN services, directly or indirectly, via roaming in a hotspot poses a problem for the user I WLAN tenninal to discover and select the right network for AAA purposes. For the user, the desired experience is similar to cellular networks, where they are able to use the service without any knowledge of how the process of network discovery and selection is done. This paper defines the scope of this problem and provides real world use-case scenarios where WLAN network discovery and selection is needed. It discusses possible access network dependent and access network-independent solutions to the problem. It then analyses these solutions in light of the use-case scenarios and suggests preferred solutions. TERMINOLOGY AAA -Authentication, Authorization and Accounting. Roaming Relationship -A business relationship between network operators that allows subscribers of one network operator to have access to mutually agreed services over the other operator's network. WIAN Access Network (AN) -The WLAN network that provides wireless connectivity for WLAN clients present in the hotspot. Home Service Network (HSN) -The Network Operator that has a direct business relationship to the user. All AAA functions are ultimately performed by the Home Service Network (HSN). Mediating Network (MN) -A Network Operator that has a Roaming Relationship with both an AN Operator and an HSN Operator. The MN Operator is needed for scenarios where the AN Operator and HSN Operator do not have a direct business relationship. WIAN Client -An 802.II-based device that enables an authorized user to connect to a WLAN Access Network.Service Set Identifier (SSID) -The ssm is a 32-character identifier that is broadcast by the 802.11 Access Points and included in the packet headers. It is used to differentiate one WLAN from another. Operators can potentially use it to identify their networks. There is no global authority at this point that can assign and guarantee a globally unique SSID to operators. Therefore, SSlDs can only be taken as a hint by the WLAN Client to associate to a WLAN before the user and the network can do mutual authentication.