ned as appropriate. SCS hide network-specific protocols and offer connectivity to circuit-switched net- works, packet-switched networks and multimedia network resources. Typically TCP/IP connectivity is offered. SCS are initially gateways to mobile bearers, only. An example of a service capability feature is 'user location'. 'User location' provides an end-user service with information concerning the location, e.g. in terms of universal latitude and longitude coordinates. 9.6.4 APPLICATION SUPPORT FUNCTIONS - FRAMEWORK FUNCTIONS - SECURITY Application Support Services (ASuS) Application support services are similar to SCS with the exception that they interface with service network resources or with external resources/systems other than core networks, e.g. a billing system or billing gateway. Service Network Application support servers provide support services for applications (end-user services) in the service network. They provide functionality that ensures the service capability features offered by the service capability servers are for example accessible, secure and manageable. Application support services consist of (but are not limited to) the following function- ality: Charging support (= OMA) Security: authentication, authorization (= OMA) Notification Directory access support (= OMA) Registration Discovery Charging support services receive charging information from applications and create standard charging streams that could be forwarded to billing systems. The overall security is reduced when opening up between applications and core net- works. Therefore some kind of firewall is necessary to protect the core networks from attacks from unauthorized users of the service network. All applications must therefore first become authenticated. Only authorized applications are permitted at the border. Before an application can use the network functionality made available through the service capability servers, authentication between the application and the framework is needed. After authentication, the discovery 