provides information on GTPP interface between Charging Gateway Function (CGF)
and Cisco Systems' licensed products running on the ASR 5x00 core platforms,
including the GGSN, P-GW, S-GW, and SGSN in General Packet Radio Service
(GPRS), Universal Mobile Telecommunications System (UMTS) data networks, 3GPP2
evolved High Rate Packet Data (eHRPD) and Long Term Evolution-System
Architecture Evolution (LTE-SAE) wireless data networks.
The Ga is the
reference point from Charging Data Function (CDF) to the CGF, which is intended
for the transport of CDRs. The CDF could either be GGSN, P-GW, S-GW, or any
other similar products.
dealing with CDRs only implies that Ga is solely related to offline charging.
The following figure
depicts the position of the Ga reference point within the overall 3GPP offline
Figure 1. 3GPP Offline Charging Architecture
As illustrated in
the above figure, the CDF in each network domain, service or subsystem is
relevant for the network side of the Ga reference point. Different mappings of
the ubiquitous offline charging functions, CDF and CGF, onto physical
implementations are possible.
protocol associated to the Ga reference point, providing functions for transfer
of CDRs from CDF to CGF, is GTPP.
Each CDF will have
an O&M; configurable address list of CGFs (Charging Gateways) to which it
can send its CDRs. The list will be organized in CGF address priority order. If
the primary CGF is not available (for example, out of service), then the CDF
will send the CDRs to the secondary CGF and so on.
Each CDR generating
function will only send the records to the CGF(s) of the same PLMN, not to
CGF(s) located in other PLMNs.
Each CGF in the PLMN
will know the other CGFs' network addresses (for example, for redundancy
reasons, to be able to recommend another CGF address). This is achieved by
O&M; configuration facilities that will enable each CGF to have a
configurable list of peer CGF addresses.
The GTPP charging
support is currently available for the following core multimedia gateway
- Evolved Packet Data
Support Node (GGSN)
Gateway/Tunnel Termination Gateway (PDG/TTG)
Network (PDN) Gateway (P-GW)
Support Node (SGSN)
Over GTP (SaMOG) Gateway