Understanding The Service Operation - Cisco ASR 5000 Series Administration Manual

Chapter 2

Understanding the Service Operation

The system provides wireless carriers with a flexible solution for providing Gateway GPRS Support Node (GGSN)
functionality for GPRS or UMTS networks.
The system functioning as a GGSN is capable of supporting the following types of subscriber data sessions:
Transparent IP: The subscriber is provided basic access to a packet data network (PDN) without the GGSN
authenticating the subscriber. Either a static or dynamic IP address can be assigned to the MS in this scenario.
Non-transparent IP: The GGSN provides subscriber authentication services for the data session. Either a static
or dynamic IP address can be assigned to the MS in this scenario.
Network-initiated: An IP Packet Data Unit (PDP) is received by the GGSN from the PDN for a specific
subscriber. If configured to support network-initiated sessions, the GGSN, will initiate the process of paging
the MS and establishing a PDP context.
PPP Direct Access: The GGSN terminates the subscribers PPP session and provides subscriber authentication
services for the data session. Either a static or dynamic IP address can be assigned to the MS in this scenario.
Virtual Dialup Access: The GGSN functions as an LAC, encapsulates subscriber packets using L2TP, and
tunnels them directly to an LNS for processing.
Corporate IP VPN Connectivity: Similar to the Virtual Dialup Access model, however, the GGSN is
configured to tunnel subscriber packets to a corporate server using a protocol such as IP-in-IP.
Prior to connecting to the command line interface (CLI) and beginning the system's configuration, there are important
things to understand about how the system supports these applications. This chapter provides terminology and
background information that must be considered before attempting to configure the system.
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Cisco ASR 5000 Series Gateway GPRS Support Node Administration Guide ▄