This network element is common to both GPRS and UMTS systems. The GGSN sits between the wireless network and the wireline data networks that interface with it. Let's begin this section by focusing on the GGSN. When a particular VPN service only applies to some release of the system, we will make that explicit. For these reasons, this chapter refers to GPRS and UMTS PS domain VPNs interchangeably. However, it is also expected that after Release 99 packet data services, networks will not be centered around the GSM/GPRS system, and consequently these capabilities are expected to be more widespread in UMTS networks (the exception being EDGE and GERAN deployments, which are unlikely to be a very common in Europe and Asia anyway, and might be limited to other regions, such as North America). These features significantly extend the range of services operators can offer, and they will be common to both GPRS and UMTS systems from Release 99 onward. New features introduced in 3GPP Release 99 standards and not present in pre-Release 99 GPRS systems, such as multiple levels of QoS per single data sessions.ĭHCP Relay at the GGSN and Mobile IP FA support at the GGSN. The differences in VPN service between the GPRS and UMTS systems are for the most part negligible. This section focuses on packet-data-based Mobile VPN services that can be provided by both the GPRS and UMTS packet data systems. Chapter 4 provides an in-depth description of both the UMTS PS domain and GPRS packet data services capabilities. Conversely, UMTS has been designed from the outset to support packet data services through its PS domain, so its performance is expected to be much more efficient and at a higher data rate than GPRS. Therefore, the GPRS system does not always deliver optimal data transmission or offer high performance and throughput data services. The GSM system, which was designed and optimized for the support of speech and circuit data services, has been augmented with packet data capabilities via the General Packet Radio Service (GPRS) overlay. Both the GSM and the UMTS systems offer packet data capabilities.
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