GBA is an application independent mechanism based on the 3GPP AKA mechanism to provide a client
and an application server with a common shared secret. This shared secret can subsequently be used to authenticate the
communication between the client and an application server.
The GCR is a register holding information about VGCS or VBS calls, the voice group or
broadcast call attributes, respectively.
Voice group or broadcast call attributes are defined for a specific voice group or broadcast call reference and include the data required to configure the conference bridge for a VGCS or VBS call and other call related attributes.
The GCR shall hold for a related MSC area for each group ID and cell from which VGCS or VBS calls can be established by mobile stations the voice group call reference or voice broadcast call reference to be used for a VGCS or VBS call to be established and an indication whether the originating MSC is the MSC responsible for that call.
If the originating MSC is not responsible for that call, the GCR shall hold the routing information identifying the MSC responsible for that call.
The location register function in the GGSN stores subscriber data received from the HLR and the SGSN. There are two
types of subscriber data needed to handle originating and terminating packet data transfer:
subscription information: the IMSI; zero or more PDP addresses.
location information: the SGSN address for the SGSN where the MS is registered.
The organisation of the subscriber data in the GGSN is defined in TS 23.008 and TS 23.060.
The procedures for information transfer between the GGSN, the SGSN and the HLR are defined in TS 23.016 and
This entity handles location management of roaming subscriber in visited network without involving HLR. The location
register function in the GLR stores subscription information and routeing information for both CS services and PS
services. This entity can be only located in a visited PLMN.
The GMLC is the first node an external Location Application accesses in the GSM
PLMN. The GMLC performs registration authorization and requests routing information from the HLR/HSS. There
may be more than one GMLC in a PLMN.
If a network delivering a call to the PLMN cannot interrogate the HLR, the call is routed to an MSC. This MSC will
interrogate the appropriate HLR and then route the call to the MSC where the mobile station is located. The MSC which
performs the routing function to the actual location of the MS is called the Gateway MSC (GMSC).
The acceptance of an interrogation to an HLR is the decision of the operator.
The choice of which MSCs can act as Gateway MSCs is for the operator to decide (i.e. all MSCs or some designated
A functional entity that interfaces the MSC/GMSC to the gsmSCF. The concept of the gsmSSF is derived from the IN
SSF, but uses different triggering mechanisms because of the nature of the mobile network.
The GUP Server is a functional entity providing a single point of access to the Generic User Profile data of a particular subscriber. The architecture does not specify or limit the physical location of the GUP Server enabling flexibility in the implementations. For further details of the GUP Server, see TS 23.240.