ETSI TS 129 219 V14.4.0 (2019-10)

TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
Policy and charging control: Spending limit reporting over Sy
reference point
(3GPP TS 29.219 version 14.4.0 Release 14)

3GPP TS 29.219 version 14.4.0 Release 14 1 ETSI TS 129 219 V14.4.0 (2019-10)

Reference
RTS/TSGC-0329219ve40
Keywords
GSM,LTE,UMTS
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ETSI
3GPP TS 29.219 version 14.4.0 Release 14 2 ETSI TS 129 219 V14.4.0 (2019-10)
Intellectual Property Rights
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Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
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Modal verbs terminology
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"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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3GPP TS 29.219 version 14.4.0 Release 14 3 ETSI TS 129 219 V14.4.0 (2019-10)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 Sy reference point . 7
4.1 Overview . 7
4.2 Sy Reference model. 8
4.3 Subscriber Spending Limits . 8
4.4 Functional ele me nts . 9
4.4.1 PCRF . 9
4.4.2 OCS . 9
4.5 Spending Limits procedures over Sy reference point . 9
4.5.1 Initial/Intermediate Spending Limit Report Request . 9
4.5.1.1 General . 9
4.5.1.2 Detailed behaviour of the PCRF . 10
4.5.1.3 The behaviour of the OCS . 10
4.5.2 Spending Limit Report. 11
4.5.2.1 General . 11
4.5.2.2 The behaviour of the OCS . 12
4.5.2.3 Detailed behaviour of the PCRF . 12
4.5.3 Final Spending Limit Report Request . 12
4.5.3.1 General . 12
4.5.3.2 Detailed behaviour of the PCRF . 13
4.5.3.3 The behaviour of the OCS . 13
5 Sy protocol . 13
5.1 Protocol support . 13
5.1.1 Use of Diameter base protocol . 13
5.1.2 Void . 13
5.1.3 Accounting functionality . 13
5.1.4 Transport protocol . 14
5.1.5 Advertising Application Support . 14
5.1.6 Use of the Supported-Features AVP . 14
5.2 Initialization and maintenance of connection and session . 15
5.3 Sy specific AVPs . 15
5.3.0 General . 15
5.3.1 Policy-Counter-Identifier AVP . 15
5.3.2 Policy-Counter-Status AVP . 15
5.3.3 Policy-Counter-Status-Report AVP . 15
5.3.4 SL-Request-Type AVP . 16
5.3.5 Pending-Policy-Counter-Information AVP . 16
5.3.6 Pending-Policy-Counter-Change-Time AVP . 16
5.4 Sy re-used AVPs . 16
5.5 Sy specific Experimental-Result-Code AVP values . 17
5.5.1 General . 17
5.5.2 Permanent Failures . 17
5.5.3 Transient Failures . 18
5.6 Sy Messages . 18
5.6.1 Command-Code Values . 18
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5.6.2 Spending-Limit-Request (SLR) command . 18
5.6.3 Spending-Limit-Answer (SLA) command . 19
5.6.4 Spending-Status-Notification-Request (SNR) command. 19
5.6.5 Spending-Status-Notification-Answer (SNA) command . 19
5.6.6 Session-Termination-Request (STR) command . 20
5.6.7 Session-Termination-Answer (STA) command . 20
Annex A (normative): User Identity for Fixed Broadband Access network convergence . 21
Annex B (informative): Change history . 22
History . 23

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Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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1 Scope
The present document provides the stage 3 specification of the Sy reference point for the present release. The functional
requirements and the stage 2 specifications of the Sy reference point are contained in TS 23.203 [2]. The Sy reference
point lies between the Policy and Charging Rule Function (PCRF) and the Online Charging System (OCS). The internal
OCS functionality for policy counter provision management pertaining to Sy is specified in TS 32.296 [16].
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 23.203: "Policy Control and Charging architecture".
[3] Void.
[4] IETF RFC 4005: "Diameter Network Access Server Application"
[5] IETF RFC 4006: "Diameter Credit Control Application".
[6] IETF RFC 5719: "Updated IANA Considerations for Diameter Command Code Allocations”
[7] IETF RFC 2234: "Augmented BNF for syntax specifications".
[8] 3GPP TS 29.213:"Policy and charging control signalling flows and Quality of Service (QoS)
parameter mapping".
[9] Void.
[10] Void.
[11] Void.
[12] Void.
[13] IETF RFC 791:"Transmission Control Protocol".
[14] IETF RFC 4960:"Stream Control Transmission Protocol".
[15] 3GPP TS 29.229:"Cx and Dx interfaces based on the Diameter protocol".
[16] 3GPP TS 32.296:"Telecommunication management; charging management; Online Charging
System (OCS) applications and interfaces".
[17] ETSI TS 283 034 v2.2.0:"Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Network Attachment Sub-System (NASS); e4 interface based
on the DIAMETER protocol".
[18] IETF RFC 3046:"DHCP Relay Agent Information Option".
[19] 3GPP TS 29.212:"Policy and Charging Control (PCC); Reference points".
[20] IETF RFC 7683:"Diameter Overload Indication Conveyance".
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[21] IETF RFC 7944: "Diameter Routing Message Priority".
[22] IETF RFC 8583: "Diameter Load Information Conveyance".
[23] IETF RFC 6733: "Diameter Base Protocol".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A
term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].
policy counter: A mechanism within the OCS to track spending applicable for a subscriber.
policy counter identifier: A reference to a policy counter in the OCS for a subscriber.
policy counter status: A label whose values are not standardized and that is associated with a policy counter's value
relative to the spending limit(s) (the number of possible policy counter status values for a policy counter is one greater
than the number of thresholds associated with that policy counter, i.e policy counter status values describe the status
around the thresholds). This is used to convey information relating to subscriber spending from OCS to PCRF. Specific
labels are configured jointly in OCS and PCRF.
spending limit: A spending limit is the usage limit of a policy counter (e.g. monetary, volume, duration) that a
subscriber is allowed to consume.
spending limit report: a notification, containing the current policy counter status generated from the OCS to the PCRF
via the Sy reference point.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
TR 21.905 [1].
DRMP Diameter Routing Message Priority
OCS Online charging system
OFCS Offline charging system
PCEF Policy and Charging Enforcement Function
PCRF Policy and Charging Rule Function
RCAF RAN Congestion Awareness Function
SLA Spending-Limit-Answer (SL-Answer)
SLR Spending-Limit-Request (SL- Request)
SNA Spending-Status-Notification-Answer (SN-Answer)
SNR Spending-Status-Notification-Request (SN- Request)
STA Session-Termination-Answer (ST-Answer)
STR Session-Termination-Request (ST- Request)
4 Sy reference point
4.1 Overview
The Sy reference point is located between the Policy and Charging Rules Function (PCRF) and the Online Charging
System (OCS). The Sy reference point enables transfer of policy counter status information relating to subscriber
spending from OCS to PCRF and supports the following functions:
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- Request of policy counter status reporting from PCRF to OCS and subscribe to or unsubscribe from spending
limit reports (i.e. notifications of policy counter status changes).
- Notification of spending limit reports from OCS to PCRF.
- Cancellation of spending limit reporting from PCRF to OCS.
Since the Sy reference point resides between the PCRF and OCS in the HPLMN, roaming with home routed or visited
access as well as non-roaming scenarios are supported in the same manner.
The stage 2 level requirements for the Sy reference point are defined in 3GPP TS 23.203 [2].
Signalling flows related to the Sy interface are specified in 3GPP TS 29.213 [8].
Refer to Annex G of 3GPP TS 29.213 [8] for Diameter overload control procedures over the Sy interface.
Refer to Annex J of 3GPP TS 29.213 [8] for Diameter message priority mechanism procedures over the Sy interface.
Refer to Annex K of 3GPP TS 29.213 [8] for Diameter load control procedures over the Sy interface.
4.2 Sy Reference model
The Sy reference point is defined between the PCRF and the OCS. The relationships between the involved functional
entities are depicted in figure 4.2.1. The overall PCC architecture is depicted in clause 3a of 3GPP TS 29.213 [8]
Sy
OCS
PCRF
Figure 4.2.1: Sy reference model
.Figure 4.2.2: Void
4.3 Subscriber Spending Limits
Policy decisions based on spending limits is a function that allows the PCRF to make policy decisions based on the
status of policy counters that are maintained in the OCS. The PCRF uses the policy counter statuses received from the
OCS as input to its policy decisions, e.g. downgrade the QoS (e.g. APN-AMBR) or modify the PCC/QoS/ADC Rules.
When the status of policy counters is first required to make a policy decision for a subscriber, the PCRF uses the Initial
Spending Limit Report Request procedure. The PCRF may request specific or all policy counter statuses to be reported
by the OCS for the user. The OCS provides the status to the PCRF of the requested policy counters, and will notify the
PCRF of any changes in the status of those policy counters. Optionally, the OCS can provide one or more pending
statuses for a requested policy counter with the times that have to be applied. The pending status of a policy counter
shall autonomously become the current status of a policy counter at the PCRF when the indicated corresponding time is
reached. Subsequently, the provided information for pending statuses of a policy counter shall overwrite the previously
received information.
NOTE 1: The mechanism for provisioning the policy counters in the OCS is out of scope of this document.
NOTE 2: A policy counter in the OCS can represent the spending for one or more services, one or more devices,
one or more subscribers, etc. The representation is operator dependent. There is no explicit relationship
between Charging-Key and policy counter.
The PCRF may request reporting for specific policy counter(s) that it is not currently subscribed and/or cancel reporting
for specific policy counter status(es) using the Intermediate Spending Limit Report Request. The PCRF may cancel
spending limit reporting for all policy counter(s) using the Final Spending Limit Report Request.
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The updated subscriber profile may also trigger the PCRF sending the Initial/Intermediate/Final Spending Limit Report
Request to the OCS to subscribed and/or cancel reporting for policy counter status(es). If spending limit reporting for a
policy counter is enabled, the OCS shall notify the PCRF of changes in the status of this policy counter (e.g. daily
spending limit of $2 reached) and optionally pending statuses of this policy counter with the activation time (e.g. due to
a billing period that will expire at midnight).
4.4 Functional elements
4.4.1 PCRF
The Policy Control and Charging Rules Function (PCRF) is a functional element that encompasses policy control
decision and flow based charging control functionalities.
The PCRF may take information on the subscriber's spending status into account in its policy decisions. The PCRF may
request spending limit reporting for policy counters from the OCS using the Initial or Intermediate Spending Limit
Report Request procedure as specified in clause 4.5.1. The PCRF may cancel spending limit reporting for specific
policy counter(s) using the Intermediate Spending Limit Report Request procedure, or for all policy counter(s) using the
Final Spending Limit Report Request procedure as specified in clause 4.5.3.
The PCRF shall have at least one active IP-CAN session to be able to initiate an Sy session to be used when required for
spending limit reporting for that subscriber. The PCRF shall terminate the Sy session when the last IP-CAN session for
that subscriber is terminated or no IP-CAN session for the same user depends on the spending status information
provided over Sy reference point.
The PCRF may use the status of each relevant policy counter as input to its policy decision as required by the decision
logic.
4.4.2 OCS
The Online Charging System (OCS), for the purpose of policy decisions based on the subscriber's spending, shall:
- maintain the policy counter statuses applicable for a subscriber.
- report the policy counter status values for the subscriber when requested to the PCRF.
- when a policy counter status changes, report the change to the PCRF.
4.5 Spending Limits procedures over Sy reference point
4.5.1 Initial/Intermediate Spending Limit Report Request
4.5.1.1 General
This procedure shall be used by the PCRF to request the status of policy counters available at the OCS, and to subscribe
or unsubscribe to updates of policy counters by the OCS.
This procedure is mapped to the Spending-Limit-Request/Answer commands specified in section 5.6.
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Table 4.5.1.1/1: Initial/Intermediate Spending Limit Report Request
Information element Mapping to Cat. Description
name Diameter AVP
User Identity Subscription-Id, C This IE shall contain the identity of the user. It shall be present in
Logical-Access- the initial request when the SL-Request-Type=INITIAL_REQUEST.
ID AVP, Physical-
Access-ID
(NOTE 1)
Request Type SL-Request-Type M This IE shall indicate whether this is the initial or a subsequent
request for the user.
Subscribed Policy Policy-Counter- O This IE shall indicate the list of policy counter identifiers to be
Counter Identifier List Identifier subscribed to. In the intermediate spending limit report request
procedure, this list overrides a previously provisioned list. If omitted
in either the Initial or Intermediate Spending Limit Report Request
procedures the PCRF requests subscription to all available policy
counters.
NOTE 1: The Logical-Access-ID AVP and Physical-Access-ID AVP are only applicable to Fixed Broadband Access
network convergence as defined in annex A.

Table 4.5.1.1/2: Initial/Intermediate Spending Limit Report Response
Information element Mapping to Cat. Description
name Diameter AVP
Policy Counter Status Policy-Counter- O If present, this information element shall contain a policy counter
Report Status-Report identifier, the current status value and if applicable pending policy
counter statuses with the activation times.
Result Result-Code or
M This IE shall contain the result of the operation.
Experimental-
Result
4.5.1.2 Detailed behaviour of the PCRF
The PCRF shall make use of this procedure when it determines for a subscriber that
- The status of policy counter(s) to which the PCRF does not have an existing subscription for status change
notifications is/are required.
- The status of one or more, but not all, policy counter(s) to which the PCRF has an existing subscription for status
change notifications are no longer required.
NOTE: The Final Spending Limit Request procedure in clause 4.5.3 is used to remove all subscriptions.
In the initial request, i.e. when the request is sent for the first time for the Subscriber, the PCRF shall set the SL-
Request-Type AVP to the value INITIAL_REQUEST (0). For subsequent requests for the same Subscriber, the PCRF
shall set the SL-Request-Type AVP to INTERMEDIATE_REQUEST (1).
For each policy counter that the PCRF requires the current status and notifications of future status changes, the PCRF
shall indicate the concerned policy counter identifiers in the request. Alternatively, the policy counter identifiers may be
omitted if the PCRF requires the current status and notifications of future status changes of all available policy counters.
4.5.1.3 The behaviour of the OCS
Upon reception of the request from the PCRF, the OCS shall check if there is an ongoing Sy session associated with the
received Session-Id AVP. If there is no Sy session and the SL-Request-Type AVP is set to INITIAL_REQUEST (0), an
Sy session is created on the OCS. If there is an Sy session and the SL-Request-Type AVP is not set to
INTERMEDIATE_REQUEST (1), the OCS shall return a response with the Result-Code set to
DIAMETER_INVALID_AVP_VALUE and with the Failed-AVP AVP containing the SL-Request-Type AVP. If there
is no Sy session and the SL-Request-Type AVP is not set to INITIAL_REQUEST (0), the OCS shall return a response
with the Result-Code AVP set to DIAMETER_UNKNOWN_SESSION_ID.
Upon reception of the request from the PCRF provided with explicit Policy Counter Identifier(s):
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If all the policy counter identifiers are known to the OCS, the OCS shall be able to subsequently notify the PCRF of any
policy counter state changes and/or additions, removal or changes of pending policy counter statuses along with their
activation time.
If a policy counter identifier is known by the OCS, but is not applicable to the subscriber (e.g. not provisioned), the
OCS may use an operator configured policy counter status to indicate this to the PCRF.
If the OCS is configured to accept the request provided with unknown policy counter identifier(s) , and if the OCS
determines that one or more policy counter identifiers are unknown, an operator configured policy counter status may
be used to indicate the policy counter identifier(s) determined as unknown by OCS. The status of known policy counter
identifier(s) shall be returned to the PCRF in the same procedure in this case.
Alternatively, if the OCS is configured to reject the request provided with unknown policy counter identifier(s), and if
the OCS determines that one or more policy counter identifiers are unknown, the OCS shall return a response with the
Experimental-Result-Code AVP set to DIAMETER_ERROR_UNKNOWN POLICY_COUNTERS and with the
Failed-AVP AVP indicating the unknown policy counter identifiers. When this failure occurs, if the SL-Request-Type
AVP is set to:
- INITIAL_REQUEST (0), then the Sy session is not created.
- INTERMEDIATE_REQUEST (1), then none of the changes in the request take effe
...