Cisco ASR 5000 Series, Обзор продукта

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GGSN Support in GPRS/UMTS Wireless Data Services
▀ Features and Functionality - Base Software
▄ Cisco ASR 5000 Series Product Overview
OL-22938-02
3GPP TS 32.015 v3.12.0 (2003-12) : 3rd Generation Partnership project; Technical Specification Group Services
and System Aspects; Telecommunication Management; Charging and billing; GSM call and event data for the
Packet Switched (PS) domain (Release 1999) for support of Charging on GGSN
3GPP TS 32.215 v5.9.0 (2005-06) : 3rd Generation Partnership Project; Technical Specification Group Services
and System Aspects; Telecommunication management; Charging management; Charging data description for
the Packet Switched (PS) domain (Release 4)
3GPP TS 29.060 v7.9.0 (2008-09) : Technical Specification; 3rd Generation Partnership Project; Technical
Specification Group Core Network; General Packet Radio Service (GPRS); GPRS Tunnelling Protocol (GTP)
across the Gn and Gp interface (Release 6)
The system supports the use of GTPP for PDP context accounting. When the GTPP protocol is used, accounting
messages are sent to the Charging Gateways (CGs) over the Ga interface. The Ga interface and GTPP functionality are
typically configured within the system's source context. As specified by the standards, a CDR is not generated when a
session starts. CDRs are generated according to the interim triggers configured using the charging characteristics
configured for the GGSN, and a CDR is generated when the session ends. For interim accounting, STOP/START pairs
are sent based on configured triggers.
GTPP version 2 is always used. However, if version 2 is not supported by the CGF, the system reverts to using GTPP
version 1. All subsequent CDRs are always fully-qualified partial CDRs. All CDR fields are R4.
Whether or not the GGSN accepts charging characteristics from the SGSN can be configured on a per-APN basis based
on whether the subscriber is visiting, roaming or, home.
By default, the GGSN always accepts the charging characteristics from the SGSN. They must always be provided by the
SGSN for GTPv1 requests for primary PDP contexts. If they are not provided for secondary PDP contexts, the GGSN
re-uses those from the primary.
If the system is configured to reject the charging characteristics from the SGSN, the GGSN can be configured with its
own that can be applied based on the subscriber type (visiting, roaming, or home) at the APN level. GGSN charging
characteristics consist of a profile index and behavior settings. The profile indexes specify the criteria for closing
accounting records based specific criteria.
Important:
For more information on GTPP group configuration, refer GTPP Accounting Configuration in GGSN
Service Configuration chapter.
Host Route Advertisement
When subscribers are assigned IP addresses from RADIUS or HLR, yet are allowed to connect to multiple GGSNs
through the use of DNS round robin or failover, the IP addresses of the subscribers can be advertised on a per user (host)
basis to the Gi network using dynamic routing, thereby providing IP reachability to these users.
IP address pools are configured on the GGSN for many reasons, although one of them is so that the pool subnets can be
automatically advertised to the network. These are connected routes and are advertised for all non-tunneling pools.
A configuration is provided to the IP pool configuration and when this option is
enabled, the subnet(s) of the pool are not added to routing table and routing protocols like OSPF and BGP do not know
of these addresses and hence do not advertise the subnet(s).
As calls come up, and addresses from this pool (with the ―explicit-route-advertise‖ flag) are used, the assigned addresses
are added to the routing table and these addresses can be advertised by OSPF or BGP through the network or the
―redistribute connected‖ command.