connectivity layer (routers). 3. The GGSN server requests an IP address from the RADIUS server. 4. The GGSN server requests (internal communication) the GGSN MGW to create a GTP tunnel end point. 5. The GGSN server sends a Create PDP context response to the SGSN server. 6. The SGSN server requests WRAN to set-up a RAB. 7. Acknowledgement on RAB request from WRAN. Radius server server server 1,8,9 1,6,7,9 STM, ATM, IP TRANSPORT Internet Intranets User data Control Figure 8.41 Example of best-effort call set up in UMTS Service Implementation server server STM, ATM, IP TRANSPORT Internet Intranets User data Control Figure 8.42 Packet data transfer phase 8. The SGSN server requests the MGW to create a GTP tunnel transfer point. 9. Activate PDP context response is sent back to the UE from the SGSN. Packet Data Transfer, Uplink See Figure 8.42. 1. A packet data unit (PDU) is sent from the UE. 2. The PDU is sent over the GTP-U tunnel between the RNC and the MGW. 3. The PDU is sent over the GTP-U tunnel between the MGW and the GGSN MGW. The PDU is sent over to the Internet/Intranet. Service Network 'Overcoming the challenges of handling a multitude of services and business-related partners.' 9.1 OBJECTIVES The overall objective is to understand the increasing role, the architecture, way of working and the potential of the service network and all its 'domains'. Such techno-economical understanding is crucial for successful service development and business. The problem in real life is indeed to limit the area. What is described in this chapter is more a kind of ideal future situation than a descrip- tion of what has yet been implemented in real networks. 9.2 CONNECTION TO PRECEDING CHAPTERS An introduction to the service network area is found in Chapter 3, see for example Section 3.11. The area is also treated in Chapter 8, section 8.7. This chapter develops the subject further. Other network (CPN, Terminal if any) Content Content Service network Applications control applications Applications Service enablers Service enabl