 in another switch site, thereby, generating inter-MSC and UMTS inter-MGW traffic. We assume that the remaining traffic terminates locally to PSTN, PLMN or stays within the UMTS network. 7.9.2 Reference Outputs in CN Dimensioning The final number of elements will depend very much on the type of configuration and capacities a supplier will offer for each CN node. Hence, in the following we provide simple reference results for completeness. [8] Deploying 3G Networks 7.9.2.1 RNC Configuration Tables 7.23 and 7.24 contain reference values for the UTRAN RNC design in terms of total number of RNCs and total traffic volumes per area. The reference traffic flows reside on values provided in Table 7.5. Table 7.23 RNC Configurations and Locations for 2002 and 2005 (750K and 1000K Subscribers) Location Capacity configuration Node Bs supporting Year 2002 Year 2005 City A 2 x L 3 X L City B L, 1 M. 2x] L City C X L, 1 X L,1x M Total (accum.) 4 x L, 1 x M, 1 S S. 6xL,1xM Large (L) = 375K subscribers, medium (M) = 240K subscribers, small (S) = 66K subscribers. The reference values will vary based on the type and configuration of the RNC pro- posed. Here we provide generic numbers in order to allow a starting point to illustrate a RNC and CN dimensioning process. The configuration includes grow surge margins and takes into account the overheads described in the preceding sections. Table 7.24 Total Traffic Volumes Through RNC for 2002 and 2005 (750K and 1000K Subscribers) Location User data (Mbps) Iu-traffic (Mbps) lub-traffic (Mbps) Year 2002 Year 2005 City A City B City C Total 7.9.2.2 Core Network Elements As illustrated in Figure 7.12, our reference CN architecture has a layered structure with total separation of the pay load transport and traffic control into the user plane and con- trol plane, respectively. The user plane builds on the MGWs to the CN through the transmission backbone. The control plane contains the common data bases (e.g. HLR/ AuC) besides the different servers (e.g. MSC, SGSN, GGSN; GMSC server) which hand