re often dependencies/relationships between the plans, which was illustrated by Figure 3.2. In a converging phase like the one that is prevailing right now, there is a technological war regarding optimal plans for the converged network. For example, a selection of numbering plans are in use, which is unfortunate. The numbering issue is discussed in Chapter 8, Section 8.8. Example of content of the plans is: Switching and routing plan: network hierarchy, routing rules etc. Numbering plan: trunk codes, subscriber numbers etc. Charging plan: principles for charging of traffic and services etc. Transmission plan: quality requirements and technique for transmission. Synchronization plan: rules for synchronization of nodes in the network. Signalling plan: signalling systems etc. Frequency plan: use of available frequency bands etc. Service plan: service range etc. Mobility management plan: anchoring ('call responsible MSC'), hand-over, roam- ing etc. Telecom business Service Dimensioning Fundamental technical plans Numbering Dependability Charging Routing Control Signalling Service Mobility management O & M production factory Switching Frequency Traffic Transmission resources Organization Synchronization M = Management system Traffic system = Network Figure 3.21 Fundamental technical plans in traffic and management systems Understanding Changing Telecommunications - Building a Successful Telecom Business In the new horizontal networks there are a lot of possible traffic cases to consider, with different transfer modes in/out at the media gateways and fairly complex layered radio interfaces. This makes these networks more complex to design than the 'monolithic' vertical networks of today. A smooth interconnection between a large and increasing number of operators can only be achieved if the operators agree on common rules at their common border, on signalling gateway protocols, routing, charging, security, management information transfer, transfer of transit calls between other operators etc. Historically, the area of F