Cisco ASR 5000 Series Administration Manual page 66

▀ How GGSN Works
Figure 13. PPP Direct Access Call Flow
1. The Mobile Station (MS) goes through the process of attaching itself to the GPRS/UMTS network.
2. The MS sends an Activate PDP Context Request message that is received by an SGSN. The message contains
information about the subscriber such as the Network layer Service Access Point Identifier (NSAPI), PDP
Type, PDP Address, Access Point Name (APN), Quality of Service (QoS) requested, and PDP configuration
options.
▄ Cisco ASR 5000 Series Gateway GPRS Support Node Administration Guide
GGSN Support in GPRS/UMTS Wireless Data Services
OL-22944-02