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▀ Introduction
Charging Collection Function
The CCF implements the CDF and CGF. The CCF will serve as the Diameter Server for the Rf interface. All network
elements supporting the CTF function should establish a Diameter based Rf Interface over TCP connections to the
DRA. The DRA function will establish Rf Interface connection over TCP connections to the CCF.
The CCF is primarily responsible for receipt of all accounting information over the defined interface and the generation
of CDR (aka UDRs and FDRs) records that are in local storage. This data is then transferred to the billing system using
other interfaces. The CCF is also responsible for ensuring that the format of such CDRs is consistent with the billing
system requirements. The CDF function within the CCF generates and CGF transfers the CDRs to the billing system.
The CDF function in the CCF is responsible for collecting the charging information and passing it on to the appropriate
CGF via the GTP' based interface per 3GPP standards. The CGF passes CDR files to billing mediation via SCP.
Charging Trigger Function
The CTF will generate CDR records and passes it onto CCF. When a P-GW service is configured as CTF, then it will
generate Flow Data Record (FDR) information as indicated via the PCRF. The P-GW generates Rf messages on a per
PDN session basis. There are no per UE or per bearer charging messages generated by the P-GW.
The service data flows within IP-CAN bearer data traffic is categorized based on a combination of multiple key fields
(Rating Group, Rating Group and Service -Identifier). Each Service-Data-Container captures single bi-directional flow
or a group of single bidirectional flows as defined by Rating Group or Rating Group and Service-Identifier.
Similarly, when S-GW service is configured as CTF, it will generate Usage Data Record (UDR) information
configurable on a per PDN basis QCI basis. Note that per bearer charging and per UE charging are no longer required.
The Diameter charging sessions to the CCF are setup on a per PDN connection basis.
Dynamic Routing Agent
The DRA provides load distribution on a per session basis for Rf traffic from CTFs to CCFs. The DRA acts like a
Diameter Server to the Gateways. The DRA acts like a Diameter client to CCF. DRA appears to be a CCF to the CTF
and as a CTF to the CCF.
The DRA routes the Rf traffic on a per Diameter charging session basis. The load distribution algorithm can be
configured in the DRA (Round Robin, Weighted distribution, etc). All Accounting Records (ACRs) in one Diameter
charging session will be routed by the DRA to the same CCF. Upon failure of one CCF, the DRA selects an alternate
CCF from a pool of CCFs.
License Requirements
The Rf interface support is a licensed Cisco feature. A separate feature license may be required. Contact your Cisco
account representative for detailed information on specific licensing requirements. For information on installing and
verifying licenses, refer to the Managing License Keys section of the Software Management Operations chapter in the
System Administration Guide.
Supported Standards
Rf interface support is based on the following standards:
IETF RFC 4006: Diameter Credit Control Application; August 2005
▄ Cisco ASR 5x00 Packet Data Network Gateway Administration Guide
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Rf Interface Support
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