d area. Practically it makes sense to dimension RNSAP signalling according to user plane dimensioning and user plane dimensioning makes sense when granularity that is available for the physical layer is taken into account. As with transport signalling, if all this information is put together an allocation of 100 kbps for each 2 Mbps for RNSAP signalling should give a solid and reasonable base line. Finally, RANAP signalling is used to change the serving RNC and for a hard handover. Other uses of RANAP signalling are, for example, paging and location reporting. Following the earlier base line of 50 kbps for each 2 Mbps should be safe but reasonable. Signalling between the Radio Network Controller and the User Element This signalling consists of some or all of the logical control channels, i.e. the broadcast control channel (BCCH), paging control channel (PCCH), dedicated control channel (DCCH) and common control channel (CCCH). These channels are established within the transport network user plane and are therefore within the acceptance/rejection decision scope of the call admission control. It is possible to judge the needed bandwidth for these signalling channels simply by simulating the results of the call admission control with real-life channel characteristics. Conversely it is of no significance to guess the needed bandwidth without knowing the algorithm used for the call admission control and how the algorithm sees these channels. Interface Dimensioning Iub Interface This interface connects the BTS and RNC. It carries CS voice and data and PS data traffic. Interaction between various transmission/transport layers is shown in Figure 3.58. As seen in the previous chapter, Transmission Network Planning and Optimisation O & M connection lub using AAL2 & AAL5 Interfaces E1. STM-1, etc PDH/SDH PDH/SDH Microwave, fibre, Copper/Microwave Microwave, fibre, copper copper Figure 3.58 Lub transport and transmission layers various kinds of services used by the subscriber are categorised under four classes of conversatio