RFC 8506
Diameter Credit-Control Application
Internet Engineering Task Force (IETF) L. Bertz, Ed. Request for Comments: 8506 Sprint Obsoletes: 4006 D. Dolson, Ed. Category: Standards Track Y. Lifshitz, Ed. ISSN: 2070-1721 Sandvine March 2019 Diameter Credit-Control ApplicationAbstract
This document specifies a Diameter application that can be used to implement real-time credit-control for a variety of end-user services such as network access, Session Initiation Protocol (SIP) services, messaging services, and download services. The Diameter Credit- Control application as defined in this document obsoletes RFC 4006, and it must be supported by all new Diameter Credit-Control application implementations. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8506.
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Table of Contents
1. Introduction ....................................................6 1.1. Requirements Language ......................................7 1.2. Terminology ................................................7 1.3. Advertising Application Support ............................9 2. Architecture Models .............................................9 3. Credit-Control Messages ........................................11 3.1. Credit-Control-Request (CCR) Command ......................11 3.2. Credit-Control-Answer (CCA) Command .......................12 4. Credit-Control Application Overview ............................13 4.1. Service-Specific Rating Input and Interoperability ........14 4.1.1. Specifying Rating Input AVPs .......................15 4.1.2. Service-Specific Documentation .....................16 4.1.3. Handling of Unsupported/Incorrect Rating Input .....16 4.1.4. RADIUS Vendor-Specific Rating Attributes ...........17 5. Session-Based Credit-Control ...................................17 5.1. General Principles ........................................17 5.1.1. Basic Support for Tariff Time Change ...............18 5.1.2. Credit-Control for Multiple Services within a (Sub-)Session ....................................19 5.2. First Interrogation .......................................23 5.2.1. First Interrogation after Authorization and Authentication .....................................25 5.2.2. First Interrogation Included with Authorization Messages .............................27 5.3. Intermediate Interrogation ................................29 5.4. Final Interrogation .......................................31 5.5. Server-Initiated Credit Re-authorization ..................32 5.6. Graceful Service Termination ..............................34 5.6.1. Terminate Action ...................................37 5.6.2. Redirect Action ....................................38 5.6.3. Restrict Access Action .............................40 5.6.4. Usage of the Server-Initiated Credit Re-authorization ...................................41 5.7. Failure Procedures ........................................41 6. One-Time Event .................................................44 6.1. Service Price Inquiry .....................................45 6.2. Balance Checks ............................................46 6.3. Direct Debiting ...........................................46 6.4. Refunds ...................................................47 6.5. Failure Procedure .........................................48 7. Credit-Control Application State Machines ......................50 8. Credit-Control AVPs ............................................59 8.1. CC-Correlation-Id AVP .....................................61 8.2. CC-Request-Number AVP .....................................62 8.3. CC-Request-Type AVP .......................................62 8.4. CC-Session-Failover AVP ...................................63
8.5. CC-Sub-Session-Id AVP .....................................64
8.6. Check-Balance-Result AVP ..................................64
8.7. Cost-Information AVP ......................................64
8.8. Unit-Value AVP ............................................65
8.9. Exponent AVP ..............................................65
8.10. Value-Digits AVP .........................................66
8.11. Currency-Code AVP ........................................66
8.12. Cost-Unit AVP ............................................66
8.13. Credit-Control AVP .......................................66
8.14. Credit-Control-Failure-Handling AVP (CCFH) ...............67
8.15. Direct-Debiting-Failure-Handling AVP (DDFH) ..............68
8.16. Multiple-Services-Credit-Control AVP .....................68
8.17. Granted-Service-Unit AVP .................................70
8.18. Requested-Service-Unit AVP ...............................71
8.19. Used-Service-Unit AVP ....................................71
8.20. Tariff-Time-Change AVP ...................................72
8.21. CC-Time AVP ..............................................72
8.22. CC-Money AVP .............................................72
8.23. CC-Total-Octets AVP ......................................72
8.24. CC-Input-Octets AVP ......................................72
8.25. CC-Output-Octets AVP .....................................73
8.26. CC-Service-Specific-Units AVP ............................73
8.27. Tariff-Change-Usage AVP ..................................73
8.28. Service-Identifier AVP ...................................74
8.29. Rating-Group AVP .........................................74
8.30. G-S-U-Pool-Reference AVP .................................74
8.31. G-S-U-Pool-Identifier AVP ................................75
8.32. CC-Unit-Type AVP .........................................75
8.33. Validity-Time AVP ........................................75
8.34. Final-Unit-Indication AVP ................................76
8.35. Final-Unit-Action AVP ....................................77
8.36. Restriction-Filter-Rule AVP ..............................78
8.37. Redirect-Server AVP ......................................78
8.38. Redirect-Address-Type AVP ................................79
8.39. Redirect-Server-Address AVP ..............................79
8.40. Multiple-Services-Indicator AVP ..........................80
8.41. Requested-Action AVP .....................................80
8.42. Service-Context-Id AVP ...................................81
8.43. Service-Parameter-Info AVP ...............................82
8.44. Service-Parameter-Type AVP ...............................82
8.45. Service-Parameter-Value AVP ..............................83
8.46. Subscription-Id AVP ......................................83
8.47. Subscription-Id-Type AVP .................................83
8.48. Subscription-Id-Data AVP .................................84
8.49. User-Equipment-Info AVP ..................................84
8.50. User-Equipment-Info-Type AVP .............................84
8.51. User-Equipment-Info-Value AVP ............................85
8.52. User-Equipment-Info-Extension AVP ........................85
8.53. User-Equipment-Info-IMEISV AVP ...........................86
8.54. User-Equipment-Info-MAC AVP ..............................86
8.55. User-Equipment-Info-EUI64 AVP ............................86
8.56. User-Equipment-Info-ModifiedEUI64 AVP ....................86
8.57. User-Equipment-Info-IMEI AVP .............................86
8.58. Subscription-Id-Extension AVP ............................87
8.59. Subscription-Id-E164 AVP .................................87
8.60. Subscription-Id-IMSI AVP .................................87
8.61. Subscription-Id-SIP-URI AVP ..............................88
8.62. Subscription-Id-NAI AVP ..................................88
8.63. Subscription-Id-Private AVP ..............................88
8.64. Redirect-Server-Extension AVP ............................88
8.65. Redirect-Address-IPAddress AVP ...........................89
8.66. Redirect-Address-URL AVP .................................89
8.67. Redirect-Address-SIP-URI AVP .............................89
8.68. QoS-Final-Unit-Indication AVP ............................89
9. Result-Code AVP Values .........................................91
9.1. Transient Failures ........................................91
9.2. Permanent Failures ........................................92
10. AVP Occurrence Table ..........................................92
10.1. Credit-Control AVP Table .................................93
10.2. Re-Auth-Request/Re-Auth-Answer AVP Table .................94
11. RADIUS/Diameter Credit-Control Interworking Model .............94
12. IANA Considerations ...........................................97
12.1. Application Identifier ...................................97
12.2. Command Codes ............................................97
12.3. AVP Codes ................................................97
12.4. Result-Code AVP Values ...................................98
12.5. CC-Request-Type AVP ......................................98
12.6. CC-Session-Failover AVP ..................................98
12.7. CC-Unit-Type AVP .........................................99
12.8. Check-Balance-Result AVP .................................99
12.9. Credit-Control AVP .......................................99
12.10. Credit-Control-Failure-Handling AVP .....................99
12.11. Direct-Debiting-Failure-Handling AVP ....................99
12.12. Final-Unit-Action AVP ...................................99
12.13. Multiple-Services-Indicator AVP ........................100
12.14. Redirect-Address-Type AVP ..............................100
12.15. Requested-Action AVP ...................................100
12.16. Subscription-Id-Type AVP ...............................100
12.17. Tariff-Change-Usage AVP ................................100
12.18. User-Equipment-Info-Type AVP ...........................100
13. Parameters Related to the Credit-Control Application .........101
14. Security Considerations ......................................101
14.1. Direct Connection with Redirects ........................102
14.2. Application-Level Redirects .............................103
15. Privacy Considerations .......................................104 15.1. Privacy-Sensitive AVPs ..................................104 15.2. Data Minimization .......................................106 15.3. Diameter Agents .........................................107 16. References ...................................................107 16.1. Normative References ....................................107 16.2. Informative References ..................................110 Appendix A. Credit-Control Sequences .............................111 A.1. Flow I ....................................................111 A.2. Flow II ...................................................113 A.3. Flow III ..................................................116 A.4. Flow IV ...................................................117 A.5. Flow V ....................................................119 A.6. Flow VI ...................................................120 A.7. Flow VII ..................................................121 A.8. Flow VIII .................................................123 A.9. Flow IX ...................................................124 Acknowledgements .................................................130 Authors' Addresses ...............................................1301. Introduction
This document specifies a Diameter application that can be used to implement real-time credit-control for a variety of end-user services such as network access, Session Initiation Protocol (SIP) services, messaging services, and download services. ("Credit-control" is sometimes abbreviated as "CC" in figures and tables throughout this document.) The Diameter Credit-Control application as defined in this document obsoletes [RFC4006], and it must be supported by all new Diameter Credit-Control application implementations. This document provides a general solution to real-time cost and credit-control. The prepaid model has been shown to be very successful -- for instance, in GSM networks, where network operators offering prepaid services have experienced a substantial growth of their customer base and revenues. Prepaid services are now cropping up in many other wireless and wire-line-based networks. In mobile networks, additional functionality is required beyond that specified in the Diameter base protocol [RFC6733]. For example, the 3GPP charging and billing requirements document [TGPPCHARG] states that an application must be able to rate service information in real time. In addition, it is necessary to check that the end user's account provides coverage for the requested service prior to initiation of that service. When an account is exhausted or expired, the user must be denied the ability to compile additional chargeable events.
A mechanism has to be provided to allow the user to be informed of the charges to be levied for a requested service. In addition, there are services such as gaming and advertising that may credit as well as debit a user account. The other Diameter applications provide service-specific authorization, and they do not provide credit authorization for prepaid users. The credit authorization shall be generic and applicable to all the service environments required to support prepaid services. To fulfill these requirements, it is necessary to facilitate credit-control communication between the network element providing the service (e.g., Network Access Server (NAS), SIP Proxy, Application Server) and a credit-control server. The scope of this specification is credit authorization. Service- specific authorization and authentication are out of scope.1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.1.2. Terminology
AAA: Authentication, Authorization, and Accounting. AA-Answer: "AA-Answer" generically refers to a service-specific authorization and authentication answer. AA-Answer commands are defined in service-specific authorization applications, e.g., [RFC7155] [RFC4004]. AA-Request: "AA-Request" generically refers to a service-specific authorization and authentication request. AA-Request commands are defined in service-specific authorization applications, e.g., [RFC7155] [RFC4004]. Credit-control: "Credit-control" is a mechanism that directly interacts in real time with an account and controls or monitors the charges related to service usage. Credit-control is a process of (1) checking whether or not credit is available, (2) credit reservation, (3) deduction of credit from the end-user account when service is completed, and (4) refunding of reserved credit that is not used.
Diameter Credit-Control server: A Diameter Credit-Control server
acts as a prepaid server, performing real-time rating and
credit-control. It is located in the home domain and is accessed
by Service Elements or Diameter AAA servers in real time, for the
purpose of price determination and credit-control before the
service event is delivered to the end user. It may also interact
with Business Support Systems.
Diameter Credit-Control client: A Diameter Credit-Control client is
an entity that interacts with a credit-control server. It
monitors the usage of the granted quota according to instructions
returned by the credit-control server.
Interrogation: The Diameter Credit-Control client uses interrogation
to initiate a session-based credit-control process. During the
credit-control process, it is used to report the used quota and
request a new one. An interrogation maps to a request/answer
transaction.
One-time event: A charging transaction session comprising a single
request and single response.
Rating: The act of determining the cost of the service event.
Service: A type of task performed by a Service Element for an
end user.
Service Element: A network element that provides a service to the
end users. The Service Element may include the Diameter
Credit-Control client or another entity (e.g., a RADIUS AAA
server) that can act as a credit-control client on behalf of the
Service Element. In the latter case, the interface between the
Service Element and the Diameter Credit-Control client is outside
the scope of this specification. Examples of Service Elements
include NASs, SIP Proxies, and Application Servers such as
messaging servers, content servers, and gaming servers.
Service event: An event relating to a service provided to the
end user.
Session-based credit-control: A credit-control process that makes
use of several interrogations: the first, a possible intermediate,
and the final. The first interrogation is used to reserve money
from the user's account and to initiate the process. Intermediate
interrogations (if any) may be needed to request a new quota while
the service is being rendered. The final interrogation is used to
exit the process. The credit-control server is required to
maintain session state for session-based credit-control.
1.3. Advertising Application Support
Diameter nodes conforming to this specification MUST advertise support by including the value of 4 in the Auth-Application-Id of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands [RFC6733].
(page 9 continued on part 2)
