Internet DRAFT - draft-hakala-aaa-diameter-cc
draft-hakala-aaa-diameter-cc
AAA Working Group Harri Hakala,
INTERNET-DRAFT Leena Mattila
Category: Standards Track Ericsson,
Draft:<draft-hakala-aaa-diameter-cc-00.txt> Juha-Pekka Koskinen,
Expires: October 2003 Marco Stura,
John Loughney,
Nokia
April 2003
Diameter Credit-control Application
Status of this memo
This document is an Internet-Draft and is subject to all provisions
of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
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This document is a product of the Authentication, Authorization and
Accounting (AAA) Working Group of the Internet Engineering Task Force
(IETF). Comments are welcome should be submitted to the mailing list
aaa-wg@merit.edu.
Abstract
This document specifies a Diameter application that is used for real-
time cost and credit-control between a service element and a credit-
control server in a service environment.
Diameter accounting messages using additional AVPs defined in the
document are used to transfer service and credit-control information
between the service element and the credit-control server.
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TABLE OF CONTENTS
1 Introduction
1.1 Requirements language
1.2 Terminology
1.3 Advertising application support
2 Architecture Model
3 Service Credit-control
3.1 Session Based Credit-control
3.1.1 First Interrogation
3.1.2 Interim Interrogation
3.1.3 Final Interrogation
3.1.4 Failure Procedures
3.2 One Time Event
3.2.1 Service Price Enquiry
3.2.2 Balance Check
3.2.3 Direct Debiting
3.2.4 Refund
3.2.5 Failure Procedures
3.3 Credit-control Session State Machine
4 Accounting AVPs
4.1 Abnormal-Termination-Reason AVP
4.2 Accounting-Correlation-Id AVP
4.3 Check-Balance-Result AVP
4.4 Cost-Information AVP
4.5 Credit-Control-Failure-Handling AVP
4.6 Currency-Code AVP
4.7 Direct-Debiting-Failure-Handling AVP
4.8 Exponent AVP
4.9 Final-Unit-Indication AVP
4.10 Granted-Service-Unit AVP
4.11 Requested-Action AVP
4.12 Requested-Service-Unit AVP
4.13 Service-Parameter-Info AVP
4.14 Service-Parameter-type AVP
4.15 Service-Parameter-Value AVP
4.16 Subscription-Id AVP
4.17 Subscription-Id-Data AVP
4.18 Subscription-Id-Type AVP
4.19 Unit-Type AVP
4.20 Unit-Value AVP
4.21 Used-Service-Unit AVP
4.22 Value-Digits AVP
5 Result-Code AVP Values
5.1 Transient Failures
5.2 Permanent Failures
6 AVP Occurrence Table
6.1 Accounting AVP Table
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7 IANA Considerations
7.1 Application Identifier
7.2 Command Codes
7.3 AVP Codes
7.4 Result-Code AVP Values
7.5 Abnormal-Termination-Reason AVP
7.6 Check-Balance-Result AVP
7.7 Credit-Control-Failure-Handling AVP
7.8 Direct-Debiting-Failure-Handling AVP
7.9 Requested-Service-Unit AVP
7.10 Subscription-Id-Type AVP
7.11 Unit-Type AVP
8 Credit-control Application related configurable parameter
9 Security Considerations
10 References
10.1 Normative
10.2 Non-Normative
11 Acknowledgements
12 Authors addresses
13 Full Copyright Statement
14 Notices
15 Expiration Date
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1 Introduction
This Diameter application, combined with the Diameter base protocol
[DIAMBASE], describes the accounting protocol that can be used for
real time cost and credit-control in a service environment.
Next generation wireless networks specify, for example the 3GPP
Charging and Billing requirements [3GPPCHARG], critical requirements
for accounting applications. The accounting application must be able
to rate accounting information in real-time. For example, for the
service environment it is vital to be able to rate service event
information instantly.
There also exists a demand for the end user credit-control. The
accounting application must be able to check the end user's account
for coverage for the requested service event charge prior to
execution of that service event. All the chargeable events related to
a specific account must be prevented from the end user when the
credit of that account is exhausted or expired.
Also a mechanism should be provided to indicate to the end user of
the charges to be levied for a chargeable event.
There are as well services such as gaming or advertising that may
credit as opposed to deducting from the end user's account.
To fulfil all these needs, a new type of accounting application is
needed, the credit-control application. This application is used for
real-time delivery of service event information in the service
environment from the service element to the credit-control server to
minimize the financial risk.
1.1. Requirements language
In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
"recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
described in [KEYWORDS].
1.2 Terminology
AAA
Authentication, Authorization and Accounting
Accounting
The act of collection of information on resource usage for the
purposes of trend analysis, auditing, billing or cost allocation.
Accounting Server
The accounting server receives accounting data from the service
elements and other devices and translates it into session records.
It acts as an interface to back-end rating, billing, and operations
support systems.
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Charging
In the telecom world charging is synonym to accounting. A function
whereby information related to a chargeable event is transferred in
order to make it possible to determine usage for which the charged
party may be billed.
Credit-control
Credit-control is a mechanism, which directly interacts in real-
time with an account and controls or monitors the charges, related
to the service usage. Credit-control is a process of checking if
credit is available, credit-reservation, reduction of credit from
the end user account when service is completed and refunding of
reserved credit not used.
Credit-control Server
It is located in the home domain and is accessed by service
elements in real-time for 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.
Diameter Credit-control Server
A Diameter credit-control server is an entity that handles credit-
control request.
Rating
The act of determining the cost of the service event.
Service
A type of task that is performed by a service element for an end
user.
Service Element
A network element that provides a service to end user. A service
element itself can include the application service providers or
application service providers can be located in an other domain.
Service Event
Any event that creates value for the end-user.
1.3 Advertising application support
Diameter nodes conforming to this specification SHOULD advertise
support by including the value of TBD (X) in the Acct-Application-Id
AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-
Answer command [DIAMBASE].
2 Architecture Model
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A service element collects service event information and reports it
to the accounting server using an accounting protocol while and/or
after services are provided to an end-user.
The accounting protocol can for example be RADIUS accounting protocol
or the Diameter base protocol with a possible Diameter application.
If real-time credit-control is required, the credit-control client in
the service element contacts the credit-control server with service
event information included before the service is provided. The
credit-control server, depending on the service event information,
MAY perform the rating of the service event, pricing of the service
event, credit check and credit-reservation from the account. The
credit-control client in the service element monitors the service
execution according to the instructions returned by the credit-
control server. After the service completion the credit-control
server deducts the money from the account.
If direct debiting/refunding is requested, the credit-control server
deducts/increases the end user's account, respectively. The service
element can also enquire the price of the service or the account
balance status from the credit-control server.
In a multi-service environment, an end user may issue an additional
service request (e.g. data service) during an ongoing service (e.g.
voice call) towards the same account; or during an active multimedia
session an additional media type is added to the session causing a
new simultaneous request towards same account. Consequently this
needs to be considered when units are granted to the services.
There can be multiple credit-control servers in the system for
reasons of redundancy and load balancing. The system can also contain
separate rating server(s) and accounts can locate in a centralized
database. System internal interfaces can exist to relay messages
between servers and an account manager. However the detailed
architecture of credit-control system and its interfaces are
implementation specific and are out of scope of this specification.
The credit-control protocol is the Diameter base protocol with the
Diameter credit-control application.
Service Element accounting
+------------+ +-----------+ protocol +--------------+
| End |<----->| +-------+ |<------------>| Accounting |
| User | +-->| | client| |<-----+ | Server |
+------------+ | | +-------+ | | +--------------+
| +-----------+ |
+------------+ | |
| End |<--+ | +--------------+
| User | +------>|Credit-control|
+------------+ credit-control | Server |
protocol +--------------+
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credit-controlThe credit-control server and accounting server in this
architecture model are logical entities. The real configuration can
combine them into a single host.
There can exist protocol transparent Diameter relays and redirect
agents between credit-control client and credit-control server. These
agents transparently support the Diameter credit-control application.
If Diameter credit-control proxies exist between the credit-control
client and the credit-control server, they MUST advertise the
Diameter credit-control application support.
3 Service Control
When an end user requests a service, the request is forwarded to a
service element in the user's home domain. In some cases it might be
possible that the service element in the visited domain can offer
service event to the end user, however a commercial agreement must
exist between the visited domain and the home domain.
The service element SHOULD authenticate and authorize the end user
before any request is sent to the credit-control server. The
authentication and authorization mechanisms are outside of the scope
of this document.
Each credit-control session MUST have globally unique Session-Id as
defined in [DIAMBASE] and it MUST NOT be changed during the lifetime
of a credit-control session.
The Diameter credit-control client in the service element may get
information from the authorization server regarding the way
accounting data shall be forwarded (accounting protocol, credit-
control protocol or both) based on its knowledge of the end user.
This means that either the accounting information is forwarded to the
accounting server as defined in [DIAMBASE]; the credit-control server
needs to be contacted before the service event is offered to the end
user or that both the accounting protocol and the credit-control
protocol can be used in parallel.
The authorization server MAY include the Accounting-Realtime-Required
AVP to determine what to do if the sending of accounting records to
the accounting server has been temporarily prevented as defined in
[DIAMBASE]. The Accounting-Realtime-Required AVP is not used by this
application. Instead of or in addition to the Accounting-Realtime-
Required AVP the authorization server MAY include the Credit-Control-
Failure-Handling AVP and Direct-Debiting-Failure-Handling AVP to
determine what to do if the sending of credit-control messages to the
credit-control server has been temporarily prevented. The usage of
Credit-Control-Failure-Handling AVP and the Direct-Debiting-Failure-
Handling AVP gives flexibility to have different failure handling for
credit-control session and one time event direct debiting. The
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credit-control server MAY override the failure handling for credit-
control session by including the Credit-Control-Failure-Handling AVP
in the Accounting-Answer.
The usage of separate AVPs makes it possible to have different
failure handling towards accounting servers and credit-control
servers, in case both should be used parallel. It is recommended that
the client complement the credit-control failure procedures with
backup accounting flow towards an accounting server. Using different
combinations of above AVPs different safety levels can be built. For
example by choosing the Credit-Control-Failure-Handling AVP equal to
CONTINUE and Accounting-Realtime-Required AVP equal to
DELIVER_AND_GRANT the service can be granted to the end user even if
the connection to the credit-control server is down but the
accounting server is able to collect the accounting information,
provided that there is information exchange taking place between the
accounting server and credit-control server.
If authentication and authorization is done based on Diameter
application the authorization server MAY include the Acct-Interim-
Interval AVP to control the operation of the device in the service
element operating as a client as defined in [DIAMBASE]. If the Acct-
Interim-Interval AVP is included then the interim interval MAY be
present in the request message sent to the credit-control server.
The Diameter credit-control server MAY override the interim interval.
It is up to the credit-control server to determine, even
independently from the requested value, the allowed interim interval
to be used for consumption of the granted service units. The credit-
control server MAY return the interim interval in the Answer message
to the credit-control client. It can be included in the Answer
message even in case it is not present in the Request message.
Alternatively the accounting interim interval can be omitted from the
Answer message. However, since interim records are also produced at
the expiry of granted service units and/or for mid-session service
events the omission of Acct-Interim-Interval does not mean that
interim records are not produced.
During authorization, the authorization server MAY return the
Accounting-Multi-Session-Id, which the Diameter credit-control client
MAY include in all subsequent accounting messages. The Accounting-
Multi-Session-Id AVP MAY include the value of the original Session-
Id. It's contents are implementation specific, but MUST be globally
unique across other Accounting-Multi-Session-Id, and MUST NOT be
changed during the life time of a credit-control session.
There are certain applications that require multiple accounting sub-
sessions. Such applications would send messages with a constant
Session-Id AVP, but a different Accounting Sub-Session-Id AVP.
If several credit sub-sessions will be used, all sub-sessions MUST be
closed separately before the closing the main session. The absence of
this AVP implies no sub-sessions are in use.
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If the credit-control client performs credit-reservation before
granting service to the end user it MUST use several interrogations
towards the credit-control server. In this case the credit-control
server MUST maintain the accounting session state.
A one-time event MAY be used when there is no need to maintain any
state in the Diameter credit-control server, for example enquiring
the price of the service.
3.1 Session Based Credit-control
For a session-based credit-control, several interrogations are
needed: the first, intermediate (optional) and the final
interrogation.
3.1.1 First Interrogation
The first interrogation MUST be sent before the Diameter credit-
control client allows any service event to the end user. The
Accounting-Record-Type is set to the value START_RECORD in the first
request message. The Subscription-Id-Data AVP SHOULD be included to
identify the end-user in the credit-control server.
If the Diameter credit-control client knows the cost of the service
event the monetary amount to be charged is included in the Requested-
Service-Unit AVP. If the Diameter credit-control client does not know
the cost of the service event, the Requested-Service-Unit AVP MAY
contain the number of requested service events and the Service-
Parameter-Info AVP SHOULD contain the service event information to be
rated by the credit-control server. The Service-Parameter-Info AVP
always refers to the requested service units.
The Event-Timestamp AVP contains the time when the service event is
requested in the service element.
The credit-control server SHOULD rate the service event and make a
credit-reservation from the end user's account that covers the cost
of the service event. If the type of the Requested-Service-Unit AVP
is money, no rating is needed but the corresponding monetary amount
is reserved from end user's account.
The credit-control server returns the Granted-Service-Unit AVP in the
Answer message to the Diameter credit-control client. The Granted-
Service-Unit AVP contains the amount of service units that the
Diameter credit-control client can provide to the end user until a
new Accounting-Request MUST be sent to the credit-control server. If
several unit types are sent in the Answer message the credit-control
client MUST handle each unit type separately. However there MUST be
maximum one instance of the same unit type in one Answer message.
When the granted service units for one unit type have been spent a
new Accounting-Request MUST be sent to the credit-control server even
though there would be service units left for other units types. The
type of the Granted-Service-Unit AVP can be time, volume, service
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specific or money depending on the type of service event. It is not
allowed to change the unit type(s) within the session.
If the credit-control server determines that no further control is
needed for the service it MAY include the result code indicating that
the credit-control is not applicable (e.g. service is free of charge)
and terminate the credit-control session.
The Accounting-Answer message MAY also include the Final-Unit-
Indication AVP to indicate that the Answer message contains the final
units for the service session. After the end user has used these
units, the Diameter credit-control client is responsible for
terminating the service session and the credit-control session by
sending the final interrogation to the credit-control server.
3.1.2 Intermediate Interrogation
When all of the granted service units for one unit type are spent by
the end user or the interim interval is expired, the Diameter credit-
control client MUST send a new Accounting-Request to the credit-
control server. In the case when the Acct-Interim-Interval is used,
it is always up to the Diameter credit-control client to send a new
request well in advance before the expiration of the previous request
in order to avoiding interruption in the service element. Even if the
granted service units reserved by the credit-control server have not
been spent upon expiration of the accounting interim interval, the
Diameter credit-control client MUST send a new Accounting-Request to
the credit-control server.
There can be also mid-session service events, which might affect the
rating of the current service events. In this case a spontaneous
updating (a new Accounting-Request) SHOULD be sent including
information related to the service event even if all the granted
service units have not been spent or the accounting interim interval
has not expired.
When the used units are reported to the credit-control server the
credit-control client will not have any units in its possession
before new granted units are received from the credit-control server.
When the new granted units are received from the credit-control
server these units apply from the point where the measurement of the
reported used units stopped.
The Accounting-Record-Type AVP is set to the value INTERIM_RECORD in
the intermediate request message. The Subscription-Id-Data AVP SHOULD
be included in the intermediate message to identify the end user in
the credit-control server.
The Requested-Service-Unit AVP contains the new amount of requested
service units. The Used-Service-Unit AVP contains the amount of used
service units measured from the point when the service became active
or, in case of interim interrogations are used during the session,
from the point when the previous measurement ended. The same unit
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types that are used in the previous message MUST be used. If several
unit types were included in the previous Answer message the used
service units for each unit type MUST be reported.
The Event-Timestamp AVP contains the time of the event that triggered
the sending of the new Accounting-Request.
The credit-control server MUST deduct the used amount from the end
user's account. It MAY rate the new request and make a new credit-
reservation from the end user's account that covers the cost of the
requested service event.
The Accounting-Answer message with the Accounting-Record-Type AVP set
to the value INTERIM_RECORD can include the Cost-Information AVP
containing the accumulated cost estimation for the session without
taking any credit-reservation into account.
The Accounting-Answer message MAY also include the Final-Unit-
Indication AVP to indicate that the Answer message contains the final
units for the service session. After the end user has used these
units, the Diameter credit-control client is responsible for
terminating the service session and the credit-control session by
sending the final interrogation to the credit-control server.
There can be several intermediate interrogations within a session.
3.1.3 Final Interrogation
When the end user terminates the service session or when all the
granted units are used after a Final-Unit-Indication AVP has been
received from the credit-control server, the Diameter credit-control
client MUST send a final Accounting-Request message to the credit-
control server. The Accounting-Record-Type AVP is set to the value
STOP_RECORD.
The Event-Timestamp AVP MAY contain the time of the session was
terminated.
The Used-Service-Unit AVP contains the amount of used service units
measured from the point when the service became active or, in case of
interim interrogations are used during the session, from the point
when the previous measurement ended. If several unit types were
included in the previous answer message the used service units for
each unit type MUST be reported.
After final interrogation the credit-control server MUST refund the
reserved credit amount not used to the end user's account and deduct
the used monetary amount from the end user's account.
The Accounting-Answer message with the Accounting-Record-Type set to
the value STOP_RECORD SHOULD include the Cost-Information AVP
containing the estimated total cost for the session in question.
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3.1.4 Failure Procedures
Since the credit-control application is based on real-time bi-
directional communication between the credit-control client and the
credit-control server, the usage of alternative destinations and the
buffering of messages are not sufficient in the event of
communication failures. Since the credit-control server has to
maintain a session state the credit-control message stream MUST not
be moved to a backup credit-control server during an ongoing credit-
control session. However, Diameter agents can perform failover to an
alternative agent when they detect a transport failure. As a
consequence the credit-control server might receive duplicate
messages. These duplicates or out of sequence messages can be
detected in the credit-control server based on the credit-control
server session state machine (section 3.3), Session-Id AVP and
Accounting-Record-Number AVP.
If a communication failure occurs during an ongoing credit-control
session the credit-control client will terminate or continue the
service depending on the value set in the Credit-Control-Failure-
Handling AVP. The Credit-Control-Failure-Handling AVP MAY be sent
from the authorization server and in the Accounting-Answer from the
credit-control server. For new credit-control sessions, failover to
an alternate credit-control server SHOULD be performed, if possible.
The timer, Tx (as defined in section 8), is used in the credit-
control client to supervise the communication with the credit-control
server.
If the credit-control server detects a failure during an ongoing
credit-control session, it will terminate the credit-control session
and return the reserved units back to the end user's account.
The supervision session timer Ts as defined in [DIAMBASE] is used in
the credit-control server.
3.2 One Time Event
The one time event is used when there is no need to maintain
accounting session state in the credit-control server.
The one time event can be used when the service element wants to know
the cost of the service event without any credit-reservation or to
check the account balance without any credit-reservation. It can be
used also for refunding service units on the user's account or direct
debiting without any credit-reservation.
3.2.1 Service Price Enquiry
The service element may need to know the price of the service event.
There might exist services offered by application service providers,
whose prices are not known in the service element. End user might
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also want to get an estimation of the price of a service event before
requesting it.
A Diameter credit-control client requesting the cost information MUST
set the Accounting-Record-Type AVP equal to EVENT_RECORD, include the
Requested-Action AVP set to PRICE_ENQUIRY and set the requested
service event information into the Service-Parameter-Info AVP in the
Accounting-Request message.
The credit-control server calculates the cost of the requested
service event, but it does not perform any account balance check or
credit-reservation from the account.
The estimated price of the requested service event is returned to the
credit-control client in the Cost-Information AVP in the Accounting-
Answer message.
3.2.2 Balance Check
The Diameter credit-control client may need only to verify that the
end user's account balance covers the cost for a certain service
without reserving any units from the account at the time of the
enquiry. This method does not guarantee that there would be credit
left when the Diameter credit-control client requests the debiting of
the account with a separate request.
A Diameter credit-control client requesting the balance check MUST
set the Accounting-Record-Type AVP equal to EVENT_RECORD, include
Requested-Action AVP set to CHECK_BALANCE and include the
Subscription-Id-Data to identify the End-User in the credit-control
server.
The credit-control server makes the balance check, but it does not do
any credit-reservation from the account.
The result of balance check (Credit/No Credit) is returned to the
credit-control client in the Check-Balance-Result AVP in the
Accounting-Answer message.
3.2.3 Direct Debiting
There are certain one-time events for which service execution is
always successful in the service environment. The delay between the
service invocation and the actual service delivery to the end user
can be sufficiently long that the use of the session based credit-
control would lead to unreasonable long credit-control sessions. In
these cases the Diameter credit-control client can use the one-time
event scenario for direct debiting. The Diameter credit-control
client SHOULD be sure that the requested service event execution
would be successful, when this scenario is used.
The Accounting-Record-Type is set to the value EVENT_RECORD and the
Requested-Action AVP set to DIRECT_DEBITING in the Accounting-Request
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message. The Subscription-Id-Data AVP SHOULD be included to identify
the End-User in the credit-control server. The Event-Timestamp AVP
contains the time when the service event is requested in the service
element.
The Diameter credit-control client can include the monetary amount to
be charged in the Request-Service-Unit AVP, if it knows the cost of
the service event. If the Diameter credit-control client does not
know the cost of the service event, then the Service-Parameter-Info
AVP SHOULD contain the service event information to be rated by the
credit-control server. The Service-Parameter-Info AVP always refers
to the requested service unit.
The credit-control server SHOULD rate the service event and deduct
the corresponding monetary amount from end user's account. If the
type of the Requested-Service-Unit AVP is money, no rating is needed
but the corresponding monetary amount is deducted from the End User's
account.
The credit-control server returns the Granted-Service-Unit AVP in the
Answer message to the Diameter credit-control client. The Granted-
Service-Unit AVP contains the amount of service units that the
Diameter credit-control client can provide to the end user. The type
of the Granted-Service-Unit can be time, volume, service specific or
money depending on the type of service event.
If the credit-control server determines that no credit-control is
needed for the service it can include the result code indicating that
the credit-control is not applicable (e.g. service is free of
charge).
For informative purposes, the Accounting-Answer message SHOULD also
include the Cost-Information AVP containing the estimated total cost
of the requested service.
3.2.4 Refund
Some services may refund service units to the end user's account, for
example gaming services.
The credit-control client MUST set Accounting-Record-Type AVP to the
value EVENT_RECORD and the Requested-Action AVP to REFUND in the
Accounting-Request message. The Subscription-Id-Data AVP SHOULD be
included to identify the End-User in the credit-control server.
The Diameter credit-control client MAY include the monetary amount to
be refunded in the Request-Service-Unit AVP, if it knows the cost of
the service event. If the Diameter credit-control client does not
know the cost of the service event, then the Service-Parameter-Info
AVP SHOULD contain the service event information to be rated by the
credit-control server. The Service-Parameter-Info AVP always refers
to the requested service unit.
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For informative purposes, the Accounting-Answer message MAY also
include the Cost-Information AVP containing the estimated monetary
amount of refunded unit.
3.2.5 Failure Procedure
There MAY exist protocol transparent Diameter relays and redirect
agents or Diameter credit-control proxies between credit-control
client and credit-control server. These agents can perform failover
procedures if they detect transport failure as described in
[DIAMBASE].
When the credit-control client detects a communication failure to the
credit-control server, its behavior depends on the requested action.
The timer Tx (as defined in section 8) is used in the credit-control
client to supervise the communication with the credit-control server.
In case the requested action is Service Price Enquiry or Balance
Check and communication failure is detected the credit-control client
SHOULD forward the request messages to an alternative credit-control
server, if possible.
If the requested action is DIRECT_DEBITING and the Direct-Debiting-
Failure-Handling AVP is set to TERMINATE_OR_BUFFER the credit-control
client SHOULD terminate the service if it can determine from the
result code or error code in the answer message that units have not
been debited. Otherwise the credit-control client SHOULD grant the
service to the end user and store the record in the credit-control
application level non-volatile storage. The credit-control client
MUST mark these request messages as possible duplicate by setting the
T-flag in the command header as described in [DIAMBASE] section 3. If
the Direct-Debiting-Failure-Handling AVP is set to CONTINUE the
service SHOULD be granted even if credit-control messages can't be
delivered. If the timer Tx expires the credit-control client MUST
continue the service and eventually buffer the request according to
the value of the Direct-Debiting-Failure-Handling AVP.
The Accounting-Request with requested action REFUND should always be
stored in the credit-control application level non-volatile storage
in case of temporary failure. The credit-control client MUST mark the
re-transmitted request message as possible duplicate by setting the
T-flag in the command header as described in [DIAMBASE] section 3.
The implementation may choose to limit the number of re-transmission
attempts and define a re-transmission interval.
Because there can appear duplicate request for various reason the
credit-control server is therefore responsible for the real time
duplicate detection. Implementation issues for duplicate detection
are discussed in [DIAMBASE] Appendix C. When the credit-control
client re-sends messages from its application level non-volatile
storage it MUST mark these request messages as possible duplicate by
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setting the T-flag in the command headers as described in [DIAMBASE]
section 3.
Only one place in the credit-control system SHOULD be responsible for
duplicate detection. If there is only one credit-control server
within the given realm the credit-control server may perform
duplicate detection. In case when more than one credit-control server
are supporting the credit-control application the accounting manager
controlling the account database MAY be responsible for duplicate
detection.
3.3 Credit-control Session State Machine
The following state machines MUST be supported for credit-control
applications.
The first two state machines are to be observed by credit-control
clients. The first one describes the session-based credit-control and
the second one event based credit-control. The third state machine
describes the credit-control session from a credit-control server
perspective.
Any event not listed in the state machines MUST be considered as an
error condition, and a corresponding answer, if applicable, MUST be
returned to the originator of the message.
In the state table, the event 'Failure to send' means that the
Diameter credit-control client is unable to communicate with the
desired destination (i.e. the answer message is not received within
the validity time of the request). This could be due to the peer
being down, or due to a physical link failure in the path to/from the
credit-control server.
The event 'Temporary error' means that the Diameter credit-control
client received a transient failure notification in the Accounting
Answer command (i.e. the peer sending back a transient failure or
temporary protocol error notification DIAMETER_TOO_BUSY, or
DIAMETER_LOOP_DETECTED in the Result-Code AVP).
The event 'Failed answer' means that the Diameter credit-control
client received non-transient failure (permanent failure)
notification in the Accounting Answer command.
The action 'store record' means that a record is stored in the
credit-control application level non-volatile storage.
The event 'Not successfully processed' means that the credit-control
server could not process the message, e.g. due to unknown end user,
account being empty or due to errors defined in [DIAMBASE].
The states PendingS, PendingI, PendingL PendingE and PendingB stand
for pending states to wait for an answer to an accounting request
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related to a Start, Interim, Stop, Event or Buffered record
respectively.
CLIENT, SESSION BASED
State Event Action New State
---------------------------------------------------------------
Idle Client or device requests Send PendingS
access accounting
start req.,
start Tx.
PendingS Successful accounting Stop Tx Open
start answer received
PendingS Failure to send, or Grant Idle
temporary error and service to
credit-control fault end user
handling equal to CONTINUE
PendingS Failure to send, or Disconnect Idle
temporary error and user/dev
credit-control fault
handling equal to TERMINATE
PendingS Tx expired and credit Disconnect Idle
Control fault handling user/dev
equal to TERMINATE
PendingS Tx expired and credit-control Grant
fault handling equal to service to Idle
CONTINUE end user
PendingS Accounting start answer Disconnect Idle
received with result code user/dev
SERVICE_ DENIED or
USER_NOT_FOUND
PendingS Accounting start answer Grant Idle
received with result code service
equal to credit-control N/A to end user
PendingS Failed accounting start answer Grant Idle
received and credit-control Service to
fault handling end user
equal to CONTINUE
PendingS Failed accounting start answer Disconnect Idle
received and credit-control user/dev
failure handling equal to
TERMINATE
PendingS User service terminated Queue PendingS
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termination
event
PendingS Change in rating condition Queue PendingS
changed
rating
condition
event
Open Granted unit elapses Send PendingI
and no final unit accounting
indication received interim req.,
start Tx.
Open Granted unit elapses Disconnect PendingL
and final unit indication send
received accounting
stop req.,
start Tx.
Open Change in rating condition Send PendingI
in queue accounting
interim req.,
Start Tx.
Open Service terminated in queue Send PendingL
accounting
stop req.,
start Tx
Open Change in rating condition Send PendingI
or interim interval elapses accounting
interim req.,
Start Tx.
Open User service terminated Send PendingL
accounting
stop req.,
start Tx
PendingI Successful accounting interim Stop Tx Open
answer received
PendingI Failure to send, or Grant Idle
temporary error and service to
credit-control fault end user
handling equal to CONTINUE
PendingI Failure to send, or Disconnect Idle
temporary error and user/dev
credit-control fault
handling equal to TERMINATE
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PendingI Tx expired and credit-control Disconnect Idle
fault handling equal to user/dev
TERMINATE
PendingI Tx expired and credit-control Grant
fault handling equal to service to Idle
CONTINUE end user.
PendingI Accounting interim answer Disconnect Idle
received with result code user/dev
SERVICE_DENIED
PendingI Accounting interim answer Grant Idle
received with result code service
equal to credit-control N/A to end user
PendingI Failed accounting interim Grant Idle
answer received and credit service to
control fault handling equal end user.
to CONTINUE
PendingI Failed accounting interim Disconnect Idle
answer received and credit user/dev
control fault handling
equal to TERMINATE
PendingI User service terminated Queue PendingI
termination
event
PendingI Change in rating Queue PendingI
condition changed
rating
condition
event
PendingL Successful accounting stop Idle
answer received
PendingL Tx expired Idle
PendingL Failure to send, or temporary Idle
error or failed answer
PendingL Change in rating condition PendingL
CLIENT, EVENT BASED
State Event Action New State
----------------------------------------------------------------
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Idle Client or device requests Send PendingE
a one-time service accounting
event req.,
Start Tx.
Idle Records in storage Send PendingB
stored
records
PendingE Successful accounting Idle
event answer received
PendingE Failure to send, temporary Indicate Idle
error or failed accounting service
event answer received, or error
Tx expired, requested
action GET_BALANCE or
PRICE_ENQUIRY
PendingE Accounting event answer Disconnect Idle
received with result code user/dev
SERVICE_ DENIED or
USER_NOT_FOUND
PendingE Accounting event answer Grant Idle
received with result code service
credit-control N/A, requested to end
action DIRECT_DEBITING user
PendingE Failure to send, temporary Grant Idle
error or failed accounting service
event answer received, or Tx to end
expired, requested user
action DIRECT_DEBITING and
fault handling equal to
CONTINUE
PendingE Failed accounting event Disconnect Idle
answer received, requested user/dev
action DIRECT_DEBITING and
fault handling equal to
TERMINATE_OR_BUFFER
PendingE Failure to send or Tx Grant Idle
expired, requested service
action DIRECT_DEBITING and to end user
fault handling equal to and store
TERMINATE_OR_BUFFER record with
T-flag
PendingE Temporary error, requested Disconnect Idle
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action DIRECT_DEBITING and user/dev
fault handling equal to
TERMINATE_OR_BUFFER
PendingE Failed accounting event Indicate Idle
answer received, requested service
action REFUND error and
delete record
PendingE Failure to send or Store record Idle
Tx expired, requested with T-flag
action REFUND
PendingE Temporary error Store record Idle
and requested action
REFUND
PendingB Successful accounting answer Delete Idle
received record
PendingB Failed accounting answer Delete Idle
received record
PendingB Failure to send or Idle
temporary error
SERVER, SESSION AND EVENT BASED
State Event Action New State
----------------------------------------------------------------
Idle Accounting start request Send Open
received and successfully accounting
processed. start
answer,
reserve units,
start Ts
Idle Accounting start request Send Idle
received, but not accounting
successfully processed. start
Answer with
Result-Code
!= SUCCESS
Idle Accounting event request Send Idle
received and successfully accounting
processed. event
answer,
debit units
Idle Accounting event request Send Idle
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received, but not accounting
successfully processed. event
Answer with
Result-Code
!= SUCCESS
Open Accounting Interim request Send Open
received and successfully accounting
processed answer,
debit used
units and
reserve
new units,
Restart Ts
Open Accounting interim request Send Idle
received, but not accounting
successfully processed. interim
Answer with
Result-Code
!= SUCCESS,
debit used
units
Open Accounting stop request Send Idle
received, and successfully accounting
processed stop answer,
Stop Ts,
debit used
units
Open Accounting stop request Send Idle
received, but not accounting
successfully processed. stop
Answer with
Result-Code
!= SUCCESS,
debit used
units
Open Session supervision timer Ts Stop Ts, Idle
expired release
reserved
units
4 Accounting AVPs
This section defines the accounting AVPs that are specific to
Diameter Credit-control Application and MAY be included in the
Diameter accounting messages [DIAMBASE].
Accounting-Request command MAY include the following additional AVPs:
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[ Subscription-Id ]
[ Requested-Action ]
*[ Requested-Service Unit ]
*[ Used-Service-Unit ]
*[ Service-Parameter-Info ]
[ Abnormal-Termination-Reason]
*[ Accounting-Correlation-Id ]
[ Credit-Control-Failure-Handling ]
Accounting-Answer command MAY include a following additional AVPs:
[ Subscription-Id ]
*[ Granted-Service-Unit ]
[ Cost-Information]
[ Final-Unit-Indication ]
[ Check-Balance-Result ]
[ Credit-Control-Failure-Handling ]
The following table describes the Diameter AVPs defined in Credit-
control application, their AVP Code values, types, possible flag
values and whether the AVP MAY be encrypted.
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Data Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
Abnormal- XXX 4.1 Enumerated | - | P | | V | Y |
Termination-Reason | | | | | |
Accounting- XXX 4.2 OctetString| - | P | | V | Y |
Correlation-Id | | | | | |
Check-Balance- XXX 4.3 Enumerated | M | P | | V | Y |
Result | | | | | |
Cost-Information XXX 4.5 Grouped | - | P | | V | Y |
Credit-Control- XXX 4.6 Enumerated | M | P | | V | Y |
Failure-Handling | | | | | |
Direct-Debiting XXX 4.8 Enumerated | M | P | | V | Y |
Failure-Handling | | | | | |
Final-Unit- XXX 4.9 Unsigned32 | M | P | | V | Y |
Indicator | | | | | |
Granted-Service- XXX 4.10 Grouped | M | P | | V | Y |
Unit | | | | | |
Requested-Action XXX 4.11 Enumerated | M | P | | V | Y |
Requested-Service XXX 4.12 Grouped | M | P | | V | Y |
Unit | | | | | |
Service-Parameter XXX 4.14 Grouped | M | P | | V | Y |
Info | | | | | |
Subscription-Id XXX 4.17 Grouped | M | P | | V | Y |
Used-Service-Unit XXX 4.22 Grouped | M | P | | V | Y |
-----------------------------------------+----+-----+----+-----+----+
4.1 Abnormal-Termination-Reason AVP
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The Abnormal-Termination-Reason AVP (AVP Code TBD) is of type
Enumerated and contains information about the reason for an abnormal
service termination in a service element.
The following reasons are defined:
SERVICE_ELEMENT_TERMINATION 0
An error occurred in the service element.
CONNECTION_TO_END-USER_BROKEN 1
The connection to the end-user is broken.
4.2 Accounting-Correlation-Id AVP
The Accounting-Correlation-Id AVP (AVP Code TBD) is type of
OctetString and contains information to correlate accounting data
generated for different components of the service, e.g. transport and
service level.
4.3 Check-Balance-Result AVP
The Check Balance Result AVP (AVP code TBD) is of type Enumerated and
contains the result of the balance check. This AVP is applicable only
when the Requested-Action AVP indicates CHECK_BALANCE in the
Accounting-Request command.
The following values are defined for the Check-Balance-Result AVP.
ENOUGH_CREDIT 0
There is enough credit in the account to cover the requested
service.
NO_CREDIT 1
There isn't enough credit in the account to cover the
requested service.
4.4 Cost-Information AVP
The Cost-Information AVP (AVP Code TBD) is of type Grouped and is
used to return the cost information of a service in the Accounting-
Answer command. The included Unit-Value AVP contains the cost
estimate (always type of money) of the service in case of price
enquiry or the accumulated cost estimation in the case of credit-
control session.
The Currency-Code specifies in which currency the cost was given.
When the Requested-Action AVP with value PRICE_ENQUIRY is included in
the Accounting-Request command the Cost-Information AVP sent in the
succeeding Accounting-Answer command contains the cost estimation of
the requested service, without any reservation being made.
The Cost-Information AVP included in the Accounting-Answer command
with the Accounting-Record-Type set to INTERIM_RECORD contains the
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accumulated cost estimation for the session without taking any
credit-reservation into account.
The Cost-Information AVP included in the Accounting-Answer command
with the Accounting-Record-Type set to EVENT_RECORD or STOP_RECORD
contains the estimated total cost for the requested service.
It has the following ABNF grammar:
<Cost-Information>::=< AVP Header: TBD >
{ Unit-Value }
{ Currency-Code }
4.5 Credit-Control-Failure-Handling AVP
The Credit-Control-Failure-Handling AVP (AVP Code TBD) is of type
Enumerated. The credit-control client uses information in this AVP to
decide what to do if the sending of credit-control messages to the
credit-control server has been for instance temporarily prevented due
to a network problem.
TERMINATE 0
When the Credit-Control-Failure-Handling AVP is set to TERMINATE
the service MUST only be granted as long as there is a
connection to the credit-control server. If the credit-control
client does not receive any Accounting-Answer message within the
Tx timer (as defined in section 8) the credit-control request is
regarded failed. The moving of already started credit-control
session to alternative server is not allowed.
This is the default behavior if the AVP isn't included in the
reply from the authorization or credit-control server.
CONTINUE 1
When the Credit-Control-Failure-Handling AVP is set to CONTINUE
the service SHOULD be granted even if credit-control messages
can't be delivered.
4.6 Currency-Code AVP
The Currency-Code AVP (AVP Code TBD) is of type Unsigned32 and
contains a currency code that specifies in which currency the values
of AVPs containing monetary units were given. It is specified using
the numeric values defined in the ISO 4217 standard.
4.7 Direct-Debiting-Failure-Handling AVP
The Direct-Debiting-Failure-Handling AVP (AVP Code TBD) is of type
Enumerated. The credit-control client uses information in this AVP to
decide what to do if the sending of credit-control messages
(Requested-Action AVP set to Direct Debiting) to the credit-control
server has been for instance temporarily prevented due to a network
problem.
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TERMINATE_OR_BUFFER 0
When the Direct-Debiting-Failure-Handling AVP is set to
TERMINATE_OR_BUFFER the service MUST be granted as long as there
is a connection to the credit-control server. If the credit-
control client does not receive any Accounting-Answer message
within the Tx timer (as defined in section 8) the credit-control
request is regarded failed. The client SHOULD terminate the
service if it can determine from the failed answer that units
have not been debited. Otherwise the credit-control client
SHOULD grant the service, store the request to application level
non-volatile storage and try to re-send the request. These
requests MUST be marked as possible duplicate by setting the T-
flag in the command header as described in [DIAMBASE] section 3.
This is the default behavior if the AVP isn't included in the
reply from the authorization server.
CONTINUE 1
When the Direct-Debiting-Failure-Handling AVP is set to CONTINUE
the service SHOULD be granted even if credit-control messages
can't be delivered.
4.8 Exponent AVP
Exponent AVP is of type Integer32 (AVP code TBD) and contains the
exponent value to be applied for the Value-Digit AVP within the Unit-
Value AVP.
4.9 Final-Unit-Indication AVP
The Final-Unit-Indication AVP (AVP Code TBD) is of type Unsigned32
and indicates that the Granted-Service-Unit AVP in the accounting
command contains the final units for the service. After these units
have expired, the Diameter credit-control client in a service element
is responsible for terminating the service and sending the
STOP_RECORD to the credit-control server.
If more than one unit types are received in the Accounting-Answer,
the Unit type which first expired SHOULD cause the termination.
If included in a command, the value of this AVP is always 1.
4.10 Granted-Service-Unit AVP
Granted-Service-Unit AVP (AVP Code TBD) is of type Grouped and
contains the amount of units that the Diameter credit-control client
can provide to the end user until the service must be released or the
new Accounting-Request must be sent. The Unit-Value AVP contains the
granted units and the Unit-Type AVP defines the type of the unit.
If the Unit-Type AVP is set to time in the Accounting-Answer command,
the Unit Value AVP specifies the granted time in seconds.
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If the Unit-Type AVP is set to volume in the Accounting-Answer
command, the Unit-Value AVP specifies the granted volume in bytes.
If the Unit-Type AVP is set to service specific in the Accounting-
Answer command, the Unit-Value AVP specifies the granted number of
service specific units (e.g. number of events, points) given in a
selected service.
If the Unit-Type AVP is set to money in the Accounting-Answer
command, the Unit-Value AVP specifies the granted monetary amount in
the given currency. If the unit type is money, a Currency-Code AVP
SHOULD be included.
It has the following ABNF grammar:
<Granted-Service-Unit>::=< AVP Header: TBD >
{ Unit-Type }
{ Unit-Value }
[ Currency-Code ]
4.11 Requested-Action AVP
The Requested-Action AVP (AVP Code TBD) is type of Enumerated and
contains the requested action being sent by Accounting-Request
command where the Accounting-Record-Type is set to EVENT_RECORD.
The following values are defined for the Requested-Action AVP:
DIRECT DEBITING 0
Direct debiting indicates that the request is to decrease the
end user's account according to information specified in the
Requested-Service-Unit AVP and/or Service-Parameter-Info AVP.
The Granted-Service Unit AVP in the Accounting-Answer command
contains the debited units.
REFUND ACCOUNT 1
Refund account indicates that the request is to increase the end
user's account according to information specified in the
Requested-Service-Unit AVP and/or Service-Parameter-Info AVP.
The Granted-Service Unit AVP in the Accounting-Answer command
contains the refunded units.
CHECK_BALANCE 2
Check balance indicates that the request is a balance check
request. In this case the checking of the account balance is
done without any credit reservation from the account. The Check-
Balance-Result AVP in the Accounting-Answer command contains the
result of the Balance Check.
PRICE_ENQUIRY 3
Price Enquiry indicates that the request is a price enquiry
request. In this case neither checking of the account balance
nor reservation from the account will be done, only the price of
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the service will be returned in the Cost-Information AVP in the
Accounting-Answer Command.
4.12 Requested-Service-Unit AVP
The Requested-Service-Unit AVP (AVP Code TBD) is of type Grouped and
contains the amount of requested units specified by the Diameter
credit-control client. The included Unit-Value AVP contains the
requested Unit-Value and the Unit-Type AVP defines the type of the
unit. A server is not required to implement all of the unit types,
and must treat unknown or unsupported unit types as invalid AVP
values.
If the Unit Type AVP is set to time in the Accounting-Request
command, the Unit-Value AVP specifies the requested time in seconds.
If the Unit-type AVP is set to volume in the Accounting-Request
command, the Unit-Value AVP specifies the requested volume in bytes.
If the Unit-type AVP is set to service specific in the Accounting-
Request command, the Unit-Value AVP specifies the requested
number of service specific units (e.g. number of events) given in a
selected service.
If the Unit-Type AVP is set to money in the Accounting-Request
command, the Unit-Value AVP specifies the monetary amount in the
given currency. If the unit type is money, a Currency-Code AVP SHOULD
be included.
It has the following ABNF grammar:
<Requested-Service-Unit>::=< AVP Header: TBD >
{ Unit-Type }
{ Unit-Value }
[ Currency-Code ]
4.13 Service-Parameter-Info AVP
The Service-Parameter-Info AVP (AVP Code TBD) is of type Grouped and
contains a service specific information used for price calculation or
rating. The Service-Parameter-Type AVP defines the service parameter
type and the Service-Parameter-Value AVP contains the parameter
value. The actual contents of these AVPs are not within the scope of
this document and SHOULD be defined in another Diameter application,
standards written by other standardization bodies, or service
specific documentation.
In case of unknown service request (e.g. unknown Service-Parameter-
Type), the corresponding answer message MUST contain error code
DIAMETER_RATING_FAILED. An Accounting Answer message with this error
MUST contain one or more Failed-AVP AVPs containing the Service-
Parameter-Info AVPs that caused the failure.
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It has the following ABNF grammar:
<Service-Parameter-Info>::=< AVP Header: TBD >
[ Service-Parameter-Type ]
[ Service-Parameter-Value ]
4.14 Service-Parameter-Type AVP
The Service-Parameter-Type AVP is of type Unsigned32 (AVP Code TBD)
and defines the type of the service event specific parameter (e.g. it
can be end-user location, service name). The different parameters and
their types are service specific and the meanings of these parameters
are not defined in this document. The Service-Parameter-Value AVP
contains the service parameter type.
4.15 Service-Parameter-Value AVP
The Service-Parameter-Value AVP is of type UTF8String (AVP Code TBD)
and contains the value of the service parameter type.
4.16 Subscription-Id AVP
The Subscription-Id AVP (AVP Code TBD) is used to identify the end
user's subscription and is of type Grouped. The Subscription-Id AVP
includes a Subscription-Id-Data AVP that hold the identifier and a
Subscription-Id-Type AVP that defines the identifier type.
It has the following ABNF grammar:
<Subscription-Id>::=< AVP Header: TBD >
{ Subscription-Id-Data }
{ Subscription-Id-Type }
4.17 Subscription-Id-Data AVP
The Subscription-Id-Data AVP (AVP Code TBD) is used to identify the
end-user and is of type UTF8String. The Subscription-Id-Type AVP
defines which type of identifier is used.
4.18 Subscription-Id-Type AVP
The Subscription-Id-Type AVP (AVP Code TBD) is of type Enumerated and
it is used to determine which type of identifier that is carried by
the Subscription-Id AVP. A server is not required to implement all
of the Subscription-Id-Types, and MUST treat unknown or unsupported
Subscription-Id-Types as invalid AVP values.
The identifier can be one of the following:
END_USER_MSISDN 0
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The identifier is in international MSISDN format, according
to the ITU-T E.164 numbering plan as defined in [E164] and
[CE164].
END_USER_IMSI 1
The identifier is in international IMSI format, according to
the ITU-T E.212 numbering plan as defined in [E121] and
[CE121].
END_USER_SIP_URL 2
The identifier is in the form of a SIP URL as defined in
[SIP].
END_USER_NAI 3
The identifier is in the form of a Network Access Identifier
as defined in [NAI].
END_USER_PRIVATE 4
The Identifier is a credit-control server private identifier.
4.19 Unit-Type AVP
The Unit-Type AVP is of type Enumerated (AVP Code TBD) and contains
the type of the unit.
The unit type can be one of the following:
CREDIT_TYPE_TIME 0
The unit is of type time, given in seconds.
CREDIT_TYPE_VOLUME 1
The unit is of type volume, given in bytes.
CREDIT_TYPE_SERVICE_SPECIFIC 2
The unit is service specific (e.g. number of events,
points, chips, services etc), given in a selected service.
CREDIT_TYPE_MONEY 3
The unit is of type money, given as a monetary value, whose
currency SHOULD be specified by the Currency-Code AVP.
4.20 Unit-Value AVP
Unit-Value AVP is of type Grouped (AVP Code TBD). The value can be
time in seconds, volume in bytes, number of service specific units or
monetary amount depending on the given unit type. The Unit-Value is a
value together with an exponent, i.e. Unit-Value = Value-Digits AVP *
10^Exponent. This representation avoids unwanted rounding off. For
example the value of 2,3 is represented as Value-Digits = 23 and
Exponent = -1. The absence of exponent part MUST be interpreted as
exponent being equal to zero.
It has the following ABNF grammar:
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<Unit-Value>::=< AVP Header: TBD >
{ Value-Digits }
[ Exponent ]
4.21 Used-Service-Unit AVP
The Used-Service-Unit AVP is of type Grouped AVP (AVP Code TBD) and
contains the amount of used units measured from the point when the
service became active or, in case of interim interrogations are used
during the session, from the point when the previous measurement
ended. The included Unit-Type AVP defines the type of the unit and
the Unit-Value AVP contains the used amount.
If the Unit Type AVP is set to time in the Accounting-Request
command, the Unit-Value AVP specifies the used time in seconds.
If the Unit-Type AVP is set to volume in the Accounting-Request
command, the Unit-Value AVP specifies the used volume in bytes.
If the Unit-type AVP is set to service specific in the Accounting-
Request command, the Unit-Value AVP specifies the used number of
service specific units (e.g. number of events) given in a selected
service.
If the Unit-Type AVP is set to money in the Accounting-Request
command, the Unit-Value AVP specifies the used monetary amount in the
given currency. If the unit type is money, a Currency-Code AVP SHOULD
be included.
It has the following ABNF grammar:
<Used-Service-Unit>::=< AVP Header: TBD >
{ Unit-Type }
{ Unit-Value }
[ Currency-Code ]
4.22 Value-Digits AVP
The Value-Digits AVP is of type Unsigned64 (AVP code TBD) and
contains the number of seconds, volume in bytes, number of service
specific units or monetary amount depending on the given Unit-Type
AVP. If decimal values are needed to present the units, the scaling
MUST be indicated with the related Exponent AVP. For example for the
monetary amount $ 0,05 the value of Value-Digits AVP MUST be set to 5
and the scaling MUST be indicated with the Exponent AVP set to -2.
5 Result Code AVP values
This section defines new Result-Code AVP [DIAMBASE] values that must
be supported by all Diameter implementations that conform to this
specification.
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The Accounting-Answer message includes the Result-Code AVP, which MAY
indicate that an error was present in the Accounting-Request message.
A rejected Accounting-Request message SHOULD cause the user's session
to be terminated.
5.1 Transient Failure
Errors that fall within the transient failures category are used to
inform a peer that the request could not be satisfied at the time it
was received, but MAY be able to satisfy the request in the future.
DIAMETER_END_USER_SERVICE_DENIED 40XX
The credit-control server denies the service request due to
service restrictions or limitations related to the end-user,
for example the end-user's account could not cover the requested
service. The possibly reported used-service-units with the ACR
are deducted.
DIAMETER_CREDIT_CONTROL_NOT_APPLICABLE 40XX
The credit-control server determines that the service can be
granted to the end user but no further credit-control is needed
for the service (e.g. service is free of charge).
5.2 Permanent Failures
Errors that fall within permanent failure category are used to inform
the peer that the request failed, and should not be attempted again.
DIAMETER_USER_UNKNOWN 50XX
The specified end user is unknown in the credit-control server.
DIAMETER_RATING_FAILED 50xx
This error code is used to inform the credit-control client that
the credit-control server cannot rate the service request due to
insufficient rating input, incorrect AVP combination or due to
an AVP or an AVP value that is not recognized or supported in the
rating. The Failed-AVP AVP MUST be included and contain a copy of
the entire AVP(s) that could not be processed successfully or an
example of the missing AVP complete with the Vendor-Id if
applicable. The value field of the missing AVP should be of
correct minimum length and contain zeroes.
6 AVP Occurrence Table
The following table presents the AVPs defined in this document, and
specifies in which Diameter messages they MAY, or MAY NOT be present.
Note that AVPs that can only be present within a Grouped AVP are not
represented in this table.
The table uses the following symbols:
0 The AVP MUST NOT be present in the message.
0+ Zero or more instances of the AVP MAY be present in the
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message.
0-1 Zero or one instance of the AVP MAY be present in the
message. It is considered an error if there are more than
once instance of the AVP.
1 One instance of the AVP MUST be present in the message.
1+ At least one instance of the AVP MUST be present in the
message.
6.1 Accounting AVP Table
The table in this section is used to represent which Credit-control
applications specific AVPs defined in this document are to be present
in the accounting messages.
+-----------+
| Command |
| Code |
|-----+-----+
Attribute Name | ACR | ACA |
------------------------------|-----+-----+
Abnormal-Termination-Reason | 0-1 | 0 |
Accounting-Correlation-Id | 0-1 | 0 |
Credit-Control-Failure- | 0-1 | 0-1 |
Handling | | |
Check-Balance-Result | 0 | 0-1 |
Cost-Information | 0 | 0-1 |
Direct-Debiting-Failure- | 0 | 0 |
Handling AVP | | |
Final-Unit-Indication | 0 | 0-1 |
Granted-Service-Unit | 0 | 0+ |
Requested-Action | 0-1 | 0 |
Requested-Service-Unit | 0-1 | 0 |
Service-Parameter-Info | 0+ | 0 |
Subscription-Id | 0-1 | 0-1 |
Used-Service-Unit | 0+ | 0 |
------------------------------|-----+-----+
7 IANA Considerations
This section contains the namespaces that have either been created in
this specification, or the values assigned to existing namespaces
managed by IANA.
7.1 Application Identifier
This specification assigns the value TBD to the Application
Identifier namespace defined in [DIAMBASE]. See section 1.3 for more
information.
7.2 Command Codes
This specification uses the value 271 from the Command code namespace
defined in [DIAMBASE].
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7.3 AVP Codes
This specification assigns the values TBD - TBD from the AVP code
namespace defined in [DIAMBASE] See section 4.0 for the assignment of
the namespace in this specification.
7.4 Result-Code AVP Values
This specification assigns the values 40XX and 50XX from the Result-
Code AVP (AVP Code 268) value namespace defined in [DIAMBASE]. See
section 5.0 for the assignment of the namespace in this
specification.
7.5 Abnormal-Termination-Reason AVP
As defined in Section 4.1, the Abnormal-Termination-Reason AVP (AVP
Code TBD) defines the values 0-1. All remaining values are available
for assignment via Designated Expert [IANA].
7.6 Check-Balance-Result AVP
As defined in Section 4.3, the Check-Balance-Result AVP (AVP Code
TBD) defines the values 0-1. All remaining values are available for
assignment via Designated Expert [IANA].
7.7 Credit-Control-Failure-Handling AVP
As defined in Section 4.6, the Credit-Control-Failure-Handling AVP
(AVP Code TBD) defines the values 0-1. All remaining values are
available for assignment via Designated Expert [IANA].
7.8 Direct-Debiting-Failure-Handling AVP
As defined in Section 4.8, the Direct-Debiting-Failure-Handling AVP
(AVP Code TBD) defines the values 0-1. All remaining values are
available for assignment via Designated Expert [IANA].
7.9 Requested-Action AVP
As defined in Section 4.11, the Requested-Action AVP (AVP Code TBD)
defines the values 0-3. All remaining values are available for
assignment via Designated Expert [IANA].
7.10 Subscription-Id-Type AVP
As defined in Section 4.17, the Subscription-Id-Type AVP (AVP Code
TBD) defines the values 0-4. All remaining values are available for
assignment via Designated Expert [IANA].
7.11 Unit-Type AVP
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As defined in Section 4.20, the Unit-Type AVP (AVP Code TBD) defines
the values 0-3. All remaining values are available for assignment via
Designated Expert [IANA].
8 Credit-control Application related parameter
Tx timer
When real-time credit-control is required, the credit-control
client contacts the credit-control server before and during the
service is provided to an end user. Due to real-time nature of
application the communication delays SHOULD be minimized, e.g. to
avoid too long service set up time experienced by the end user. The
Tx timer is introduced to control the waiting time in the client in
the PENDING state.
The recommended value is 10 seconds.
Credit-Control-Failure-Handling and Direct-Debiting-Failure-Handling
Client implementations may offer the possibility to locally
configure these AVPs. In such a case their value and behavior is
defined in section 4.5 for the Credit-Control-Failure-Handling and
in section 4.7 for the Direct-Debiting-Failure-Handling.
The credit control server may override the failure handling by
including for credit control session by including the Credit-
Control-Failure-Handling AVP in the Accounting-Answer command.
9 Security Considerations
The security models as defined in the Diameter base protocol
[DIAMBASE] applies to this application too.
10 References
10.1 Normative
[DIAMBASE] P. Calhoun, J. Arkko, E. Guttman, G. Zorn, J. Loughney
"Diameter Base Protocol", IETF work in progress.
[3GPPCHARG] 3rd Generation Partnership Project; Technical Specification
Group Services and System Aspects, Service aspects;
Charging and Billing, (release 5), 3GPP TS 22.115 v. 5.2.1,
2002-03
[SIP] M. Handley, H. Schulzrinne, E. Schooler, J. Rosenberg, G.
Camarillo, A. Johnston, J. Peterson, R. Sparks
"SIP: Session Initiation Protocol", RFC 3261. June 2002.
[NAI] Aboba, Beadles "The Network Access Identifier." RFC 2486.
January 1999.
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[E164] Recommendation E.164/I.331 (05/97): The International
Public Telecommunication Numbering Plan. 1997.
[CE164] Complement to ITU-T Recommendation E.164 (05/1997):"List of
ITU-T Recommendation E.164 assigned country codes", June
2000.
[E212] Recommendation E.212 (11/98): The international
identification plan for mobile terminals and mobile users.
1998.
[CE212] Complement to ITU-T Recommendation E.212 (11/1997):" List
of mobile country or geographical area codes ", February
1999.
[IANA] Narten, Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October
1998
10.2 Non-Normative
[KEYWORDS] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[ACCMGMT] B.Aboba, J.Arkko, D.Harrington. "Introduction to Accounting
Management", RFC 2975, October 2000.
11 Acknowledgement
The authors would like to thank Paco Marin at Vodafone R&D and our
colleagues with Ericsson and Nokia for their comments and
suggestions.
12 Author's Address
Harri Hakala
Oy L M Ericsson Ab
Joukahaisenkatu 1
20520 Turku
Finland
Phone: +358 2 265 3722
EMail: Harri.Hakala@ericsson.fi
Leena Mattila
Oy L M Ericsson Ab
Joukahaisenkatu 1
20520 Turku
Finland
Phone: +358 2 265 3731
EMail: Leena.Mattila@ericsson.fi
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Juha-Pekka Koskinen
Nokia Networks
Hatanpaanvaltatie 30
33100 Tampere
Finlad
Phone: +358 7180 74027
Email: juha-pekka.koskinen@nokia.com
Marco Stura
Nokia Networks
Valimotie 21
00380 Helsinki
Finland
Phone: +358 7180 64308
Email: marco.stura@nokia.com
John Loughney
Nokia Research Center
Itamerenkatu 11-13
00180 Helsinki
Finland
Phone: +358 50 483 642
Email: John.Loughney@nokia.com
13 Full Copyright Statement
Copyright (C) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished to
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or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
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included on all such copies and derivative works. However, this docu-
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copyright notice or references to the Internet Society or other
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This document and the information contained herein is provided on an
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TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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14 Notices
The IETF takes no position regarding the validity or scope of any
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this document or the extent to which any license under such rights
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The IETF invites any interested party to bring to its attention any
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15 Expiration Date
This memo is filed as <draft-ietf-aaa-diameter-cc-00.txt> and expires
in October 2003.
Hakala et al. expires September 2003 [Page 38]
