nd MGW1. A signalling link set is also created between the RNC and MGW, but this link set is based on the SAAL (signalling ATM adaptation layer), used as transport for MTP3b messages. For RANAP, the MSS has a signalling route towards the RNC destination. Similarly, the RNC needs a signalling route towards the MSS. In these route sets, the MGW1 is defined as an STP and also plays the role of a signalling gateway between broadband SS7 signalling on the Iu-CS interface and SIGTRAN on the Mc interface. Once the MTP layer components have been created and the SCCP has been created as the MTP level service in the MSS, then SCCP level configuration data can be created. CS Core Detailed Network Planning SPC=358h MSC Server RANAP entity RANAP over SCCP/M3UA RANAP entity MTP level lu_cs(RANAP over SCCP/SAAL) MGW 1 SPC=400h GT address=3584098989 Figure 4.27 SCCP configuration BICC and SIP Signalling The UPDR parameter is used as a link between the control plane and the user plane. For incoming calls, the operator configures the UPDR parameter to the circuit group data, while for outgoing calls, the operator configures the UPDR parameter to the route data (Figure 4.28). On a per call basis, the value of the UPDR is delivered to a user plane control application to be used as an input attribute in several phases of the user plane analysis along with many other input attributes. Both BICC and SIP signalling have a similar behaviour in this respect. Control Plane ROUTE data UPDR=5 MSC Server many other attributes User Plane user plane analysis UPD-2 Figure 4.28 UPDR parameter on the outgoing side Core Network Planning and Optimisation Control Plane analysis Plane analysis Figure 4.29 Logical hierarchy of routing levels in the MSS In Figure 4.28 the UPDR value 5 is read from the outgoing ROUTE data. It is used as an input attribute for the user plane analysis with many other attributes as defined in the user plane analysis attributes. Analysis results for UPD = 2 means that two MGWs belonging to the UPD2 are allowed to be used for