book. Among interworking FPs that will be briefly illustrated in this chapter are: Services, in the form of VHE. QoS, which is maybe the trickiest. Distribution of deteriorations. Security interworking examples. Indirectly security is concerned, when two networks utilize the same AAA in the HSS system. Routing. Gateways between networks, break out, routing via roaming operators, routing to own ISP. Charging. Charging when roaming. Mobility management (roaming). When describing success factors in the visions pub- lished by the Wireless World research forum, the forum stresses seamless service provisioning across a multitude of wireless systems. Signalling, in the form of PDP context between GPRS and a data network. Gateway protocols are mentioned. See Figure 15.6. Network management information in the actor interface is necessary for e2e supervision, handling of alarms etc. The connectivity oriented plans are more autonomous, particularly at the first layers of the OSI model, and therefore less critical. Understanding Changing Telecommunications - Building a Successful Telecom Business Telecom business Service Service management Service, security, QoS Service, security, QoS Dimensioning Numbering Numbering Charging Routing Charging Routing Signalling Signalling Dependability Mobility managem. Mobility managem. Switching Frequency Switching Frequency Organization Transmission Transmission Synchronization Synchronization Network 1 Network 2 Management system Management interworking Operator 1 Figure 15.6 The interconnect plan contains interworking between other plans, in particular in control and service layers E2e security is of particular interest to what are called e-workers, equipped with a laptop and a mobile. The e-worker workplace varies a lot: central office, local offices, the home, customer locations, airports and other hot spots. However, let us start with reference points and SLAs. 15.4 DEFINITION OF AN ACTOR INTERFACE REFERENCE POINT A reference point is a set of conformance specifications for end-to-en