ration requires advanced inter-node signalling communication. To get an adequate connection one may have to define aspects such as addressing, routing, QoS, security and billing. The choice of parameters is related to what particular service is chosen. In mobile networks, such as GPRS, this FP type information is conveyed in messages called PDP context. Similar information for the IP connectivity core is carried BICC IP Bearer Control Protocol (IPBCP) (See also sections 14.3, 14.5 and 15.8.). Other (CPN, The control layer network if any) Content content Terminal Service network Appl. protocol, such Appl. Applications as HTTP Service enablers Service enablers Access dependent SIP, H.323, BICC, ISUP IW sign singalling, or SIP, Gateway control protocol H.323 UNI(ATM) PNNI(ATM), OSPF, RIP Access Core connectivity Media gateway Might be one network element, only Figure 14.1 Position of the control network in the reference model Understanding Changing Telecommunications - Building a Successful Telecom Business. Edited by A. Olsson © 2004 John Wiley & Sons, Ltd ISBN: 0-470-86851-1 Understanding Changing Telecommunications - Building a Successful Telecom Business Regarding intelligence, the traditional IN SCP nodes are part of the control layer, assisting the control servers. In addition, IN based control functions are- or will- be implemented in the service layer, See for example Figure 8.7 in Chapter 8. Much traffic can manage without the control layer. Connectionless best effort IP traffic is a good example, leased lines is another. As indicated in Chapter 12, there is an internal control function in the connectivity layer as well, serving data oriented traffic in IP, ATM and other networks. Both ordinary voice and data communication have managed without a service layer, but this will change with an increasing number of service offerings beyond voice. The development will increase the business role of the service layer. The control layer and the connectivity layer will serve the service layer more and more by means of