net, one unit will act as a master and the other(s) as slave(s) for the duration of the piconet connection. Several piconets can be established and linked together ad hoc, where each piconet identified by a different frequency hopping sequence. All users participating on the same piconet are synchronized to this hopping sequence. The topology can best be described as a multiple piconet structure. Control Network 14.1 INTRODUCTION In Chapters 11, 12 and 13 we reviewed traffic resources. We now need to understand how to control and use them in order to create a successful business. The services develop towards multimedia handling. The control layer responds with the intelligence of an IP multimedia subsystem and deployment of more advanced control network signaling, mainly based on the SIP protocol. An introduction to the subject of control was included in Chapter 3 (See section 3.2.1). The control network cooperates with the service layer, subscriber equipment and with other networks, in order to create adequate end-to-end connections in the connectivity layer. The cooperation 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 Te