1st Modified Section
For the purposes of the present document the following symbols apply:
AInterface between an MSC and a BSC.
BpReference point for the CDR file transfer from the GPRS CGF to the BD.
CInterface between a HLR and a SMSC.
DInterface between a MSC and a HLR.
EInterface between a MSC and a SMSC.
GaReference point between a CDF and the CGF for CDR transfer.
GbInterface between an SGSN and a BSC.
GcInterface between an GGSN and an HLR.
GdInterface between an SMS-GMSC and an SGSN, and between a SMS-IWMSC and an SGSN.
GeInterface between a SGSN and a CAMEL GSM SCF
GfInterface between an SGSN and an EIR.
GiInterface between the Packet-Switched domain and an external packet data network.
GnInterface between two GSNs within the same PLMN.
GpInterface between two GSNs in different PLMNs.
GrInterface between an SGSN and an HLR.
kbit/sKilobits per second. 1 kbit/s = 210 bits per second.
Mbit/sMegabits per second. 1 Mbit/s = 220 bits per second.
RReference point between a non-ISDN compatible TE and MT. Typically this reference point supports a standard serial interface.
RoOnline Charging Reference Point between a 3G network element and the OCS.
UmInterface between the Mobile Station (MS) and the GSM fixed network part.
UuInterface between the Mobile Station (MS) and the UMTS fixed network part.
Next Modified Section
4.1High level GPRS architecture
Figure 4.1 shows a high level overview of the GPRS system architecture. Each PLMN has two access points to GPRS services, the radio interface (labelled Um in A/Gb mode and Uu in Iu mode) used for mobile access and the R reference point used for origination or reception of messages. There is an inter PLMN interface labelled Gp that connects two independent GPRS packet domain networks for message exchange.
There is also a PLMN to packet data network reference point called Gi. Gi is defined in 3GPP TS 29.061 .