4Core Network Planning and Optimisation
4.1 Basics of Core Network Planning
4.1.1 Scope of Core Network Planning
The core network in GSM is basically the circuit core. In GPRS, EDGE and UMTS, it has two components, the circuit core and the packet core, which are responsible for voice and data, respectively. In GSM, core or circuit core network planning is also known as switch planning, because this planning is mainly related to the mobile switching centre or MSC, also called ‘switch’ (Figure 4.1).
Figure 4.1 Scope of core network planning.
Core network planning in GSM consists of network elements such as MSC, VLR, HLR, AC, and EIR.
4.1.2 Elements of the Core Network
4.1.2.1 MSC/VLR
The MSC is the core elements of the network sub‐system. It is responsible for the switching of subscriber calls and thus is also known as a ‘switch’. It is also responsible for functions such as traffic management, paging, and collection of charging related information. Apart from this, the MSC also acts as an interface between the network and the networks of other operators and PSTN networks. Another important element that is hosted in an MSC is the VLR or visitor location register. The VLR contains the information on the subscribers that is handled by the MSC at a given moment. Owing to the nature of its functionality, the VLR participates in call processing and mobility management functions ...