The CBC is responsible for the management of CBS (cell broadcast service) messages and for determining the CBS delivery parameters
of the BSS/RNS. The CBC may be connected to several BSCs/RNCs. The CBC is regarded to be integrated as a node
into the core network.
The CDRs produced by the CDF are transferred immediately to the Charging Gateway Function (CGF) via the Ga
reference point. The CGF acts as a gateway between the 3GPP network and the BD. It uses the Bx reference point for
the transfer of CDR files to the BD. The entity relationship between the CDF and the CGF is m:1, i.e. one or more
CDFs may feed CDRs into a single CGF.
The CN is constituted of a Circuit Switched (CS) domain and a Packet Switched (PS) domain (which includes GPRS
and EPC). These two domains differ by the way they support user traffic.
These two domains are overlapping, i.e. they contain some common entities. A PLMN can implement only one domain
or both domains.
The Charging Rules Function provides Service Data Flow level Charging Rules to the TPF (Traffic Plane Function) and informs AF about bearer session events. The CRF makes the Charging Rule decisions which may be based on the session and media related information obtained from the AF via the Rx reference point, the bearer and subscriber related information obtained from the TPF over the Gx reference point, and subscriber and service related data the CRF may be aware of.
The CRF shall provision Charging Rules the TPF via the Gx reference point. The CRF may also provide policy control like functions based on Charging Rules provisioning to the TPF.
The CRF reports, via the Rx reference point, bearer events from the TPF to the AF, e.g. bearer release and bearer
The CSCF can act as
P-CSCF (Proxy CSCF),
S-CSCF (Serving CSCF),
E-CSCF (Emergency CSCF), or
I-CSCF (Interrogating CSCF).
The P-CSCF is the first contact point for the UE within the IM subsystem (IMS); the S-CSCF actually
handles the session states in the network; the E-CSCF handles certain aspects of emergency sessions such as routing an
emergency request to the correct emergency centre or PSAP; the I-CSCF is mainly the contact point within an
operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber
currently located within that network operator's service area.
The CS domain refers to the set of all the CN entities offering "CS type of connection" for user traffic as well as all the entities supporting the related signalling. A "CS type of connection" is a connection for which dedicated network resources are allocated at the connection establishment and released at the connection release.
This component is PSTN/PLMN transport termination point for a defined network and interfaces UTRAN with the core
network over Iu.
A CS-MGW may terminate bearer channels from a switched circuit network and media streams from a packet network
(e.g. RTP streams in an IP network). Over Iu, the CS-MGW may support media conversion, bearer control and payload
processing (e.g. codec, echo canceller, conference bridge) for support of different Iu options for CS services
(AAL2/ATM based as well as RTP/UDP/IP based).
Interacts with MGCF, MSC server and GMSC server for resource control.
Owns and handles resources such as echo cancellers etc.
May need to have Codecs.
The CS-MGW will be provisioned with the necessary resources for supporting UMTS/GSM transport media. Further
tailoring (i.e. packages) of the H.248 may be required to support additional Codecs and framing protocols, etc.
The CS-MGW bearer control and payload processing capabilities will also need to support mobile specific functions
such as SRNS relocation/handover and anchoring. It is expected that current H.248 standard mechanisms can be
applied to enable this.
The CSS is the entity in the VPLMN storing and managing CSG subscription-related information for roaming UEs to
enable VPLMN Autonomous CSG Roaming (see
The CSS is responsible for holding the following user related information:
CSG membership granted to the subscriber during his stay in the VPLMN, i.e. list of CSG IDs and associated
User Location information: the CSS stores the location information of the subscriber for subsequent update of
the CSG subscription information at the MME, SGSN and VLR upon subscription change.
The CSS consists of the following functionalities:
download of the CSG subscription information upon request from the serving MME, SGSN and VLR, through
the S7a, S7d, Ghv and Hv interfaces, to enable roaming subscribers to access to the PS and CS Domain services
via CSG cells;
service provisioning, including updating the appropriate serving entities (i.e. MME, SGSN and VLR) with
modifications of the the CSG membership granted to the subscriber.
The organisation of the subscriber data is outlined in
TS 23.008. It also indicates which numbers and identifiers
specified in TS 23.003 are stored in the CSS.