ections can be made using LANs, IP trunks, etc. depending on the type of connection switches (or facility) the core network element has. Aspects such as planning of IP addressing schemes usually accompany this. The naming and numbering conventions remain similar to those in GSM core network planning, with destinations, sub-destinations and circuit groups clearly defined. Signalling points, signalling links, signalling link sets, etc., are defined also in the detailed plan. Signalling plans are based on the concepts discussed in Chapter 4. Differentiation between the subscribers of different networks can be done by IMSI analysis. Figure 9.6 Simplified example of CS voice network plan DETAILED NETWORK PLANNING Example 1: Naming of the circuit groups Assume that a network shown in example is coming up for an operator Cite-Telecom. Circuit groups can be named as: CTTMSC2 Where CT is the name of the operator (CT); MSC gives the destination code, while 2 stands for the exchange terminal. Based on the scheme decided by the core network engineers and network operator taking into consideration equipment specifications. Transit Layer Planning of the transit layer (a concept similar to that of transit layer planning in Chapter 4) is another concept to be taken care of during the detailed planning process. We have seen earlier the necessity for a transit layer; however, in a third-generation CS core network the transit layer is planned for MGWs and MSCs instead of just MSCs in GSM core networks. The planning fundamentals remain the same, but note that the need for a transit layer applies only in the ATM-backbone network, not in an IP-backbone network. One such example, with the traffic, is shown in Figure 9.7. EXT 1 MSC 1 MSC 3 MSC 2 EXT 3 EXT 2 Figure 9.7 Traffic routing Parameter Planning The final aspect of detailed planning is parameter planning. Parameters are defined for configuration of the exchange terminals, traffic routing, signalling, circuit groups, destina- tion and sub-destinations, etc. Although the number of 