RFC 4006

Q: What does the Introduction section cover in RFC 4006 — Diameter Credit-Control?

The Introduction section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 4006 — Diameter Credit-Control. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Credit-Control Commands section cover in RFC 4006 — Diameter Credit-Control?

The Credit-Control Commands section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 4006 — Diameter Credit-Control. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Credit-Control Flow section cover in RFC 4006 — Diameter Credit-Control?

The Credit-Control Flow section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 4006 — Diameter Credit-Control. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Key AVPs section cover in RFC 4006 — Diameter Credit-Control?

The Key AVPs section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 4006 — Diameter Credit-Control. This content is part of the BLACKLABS RFC Reference Library.

Q: What does the Security Considerations section cover in RFC 4006 — Diameter Credit-Control?

The Security Considerations section provides detailed technical specifications, security considerations, and implementation guidance as documented in RFC 4006 — Diameter Credit-Control. This content is part of the BLACKLABS RFC Reference Library.

BLACKLABS

Diameter Credit-Control Application

Standards Track

August 2005

Abstract: The Diameter Credit-Control Application (DCCA) provides real-time credit control for various services. In 3GPP, it is the foundation for the Gy/Ro online charging interface and the Gx policy charging control interface.

Canonical source: https://www.rfc-editor.org/rfc/rfc4006 | IETF Datatracker

1. Introduction

▶

DCCA enables real-time credit management for prepaid and postpaid services. The credit-control client (e.g., PGW, PCEF) requests credit from the credit-control server (OCS) before, during, and after service delivery.

In 3GPP, DCCA is used on the Gy interface (PGW/UPF to OCS) for online charging and adapted for the Gx interface (PCEF to PCRF) for policy and charging control.

2. Credit-Control Commands

▶

Command	Code	CC-Request-Type	Description
CCR/CCA	272	INITIAL_REQUEST (1)	Session start — reserve initial credit
CCR/CCA	272	UPDATE_REQUEST (2)	Mid-session — request additional credit or report usage
CCR/CCA	272	TERMINATION_REQUEST (3)	Session end — report final usage
CCR/CCA	272	EVENT_REQUEST (4)	One-time event (SMS, MMS)

3. Credit-Control Flow

▶

  UE         PGW/PCEF              OCS (Credit Server)
|            |                        |
|  Service   |                        |
|  Request   |                        |
|----------->|                        |
|            |  CCR (INITIAL)         |
|            |  [Service-Id, Rating-  |
|            |   Group, Requested-    |
|            |   Service-Unit]        |
|            |----------------------->|
|            |                        |
|            |         CCA (2001 OK)  |
|            |   [Granted-Service-    |
|            |    Unit, Validity-Time]|
|            |<-----------------------|
|            |                        |
|  Service   |                        |
|  Granted   |                        |
|<-----------|                        |
|            |                        |
| (Usage...) |                        |
|            |  CCR (UPDATE)          |
|            |  [Used-Service-Unit,   |
|            |   Requested-Service-U] |
|            |----------------------->|
|            |         CCA (2001 OK)  |
|            |<-----------------------|
|            |                        |
| (Session   |  CCR (TERMINATION)     |
|  End)      |  [Used-Service-Unit]   |
|            |----------------------->|
|            |         CCA (2001 OK)  |
|            |<-----------------------|

4. Key AVPs

▶

AVP	Code	Description
CC-Request-Type	416	INITIAL/UPDATE/TERMINATION/EVENT
CC-Request-Number	415	Sequence number within session
Requested-Service-Unit	437	Credit amount requested (volume/time/events)
Granted-Service-Unit	431	Credit amount granted by OCS
Used-Service-Unit	446	Usage reported by client
Validity-Time	448	Time (seconds) the granted units are valid
Rating-Group	432	Service category for rating
Service-Identifier	439	Specific service ID

5. Security Considerations

▶

Credit-control messages contain sensitive billing data — transport MUST be secured
Replay attacks on CCR could cause double-charging — End-to-End ID provides protection
Credit-control server must enforce rate limiting to prevent credit exhaustion attacks
Session state must be synchronized between client and server to prevent billing discrepancies