library.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. SGSN-to-GGSN (Gn) and GGSN-to-PDN (Gi) Interface Chapter 10 Figure 10-19 Virtual dial-up. Internet Intranet/ Tunnel NetID GTP Tunnel (PDP Context) DNS/DHCP Server L2TP over IPSec tunnel RADIUS A permanent IPSec SA is used. A one-to-one GTP tunnel to L2TP session mapping is used. GGSN is linked to Circuit Emulating Switch (CES) via PPP/L2TP. GGSN is LAC. CES is LNS. LNS provides user configuration. Authentication (RADIUS, LDAP, proprietary). Private IP address (remote DHCP RADIUS). The PPP connection performs user authentication. IPSec SA performs IP data frame encryption. As seen in this chapter, the application is what really makes GPRS work. Although some of the scenarios played out in this chapter are not yet ready to roll out, the concept is exactly what corporate users and providers will negotiate in the future. It is through the converged application and tech- nology that will make or break the acceptance of GPRS in the beginning stages of implementation. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. CHAPTER Future Enhancements and Services Future Enhancements and Services Chapter 11 Objectives Upon completion of this chapter, you should be able to Describe the concept of the HSCSD network. Discuss the evolution of EGPRS and EDGE. Understand what UMTS is all about. Describe the various other enhancements of 3G. Understand how ETSI and ANSI are collaborating with the developments. Mobile Evolution Get ready! As the convergence of wireless technology and the Internet continue at an escalating pace, the new possibilities created by third- generation (3G) and fourth-generation (4G) technologies appear endless. Preparing for the revolution, existing Time Division Multiple Access (TDMA) operators mus