ETSI TS 126 517 V17.1.0 (2023-01)

LTE; 5G; 5G Multicast-Broadcast User Services; Protocols and Formats (3GPP TS 26.517 version 17.1.0 Release 17)

RTS/TSGS-0426517vh10

General Information

• Status: Not Published
• Technical Committee: 3GPP SA 4 - Codec
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 10-Jan-2023

Standards Content (Sample)

TECHNICAL SPECIFICATION
LTE;
5G;
5G Multicast-Broadcast User Services;
Protocols and Formats
(3GPP TS 26.517 version 17.1.0 Release 17)


3GPP TS 26.517 version 17.1.0 Release 17 1 ETSI TS 126 517 V17.1.0 (2023-01)

Reference
RTS/TSGS-0426517vh10
Keywords
5G,LTE
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ETSI
3GPP TS 26.517 version 17.1.0 Release 17 2 ETSI TS 126 517 V17.1.0 (2023-01)
Intellectual Property Rights
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Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
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Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
3GPP TS 26.517 version 17.1.0 Release 17 3 ETSI TS 126 517 V17.1.0 (2023-01)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 7
2 References . 7
3 Definitions of terms, symbols and abbreviations . 7
3.1 Terms . 7
3.2 Symbols . 7
3.3 Abbreviations . 8
4 System overview . 8
5 MBS User Service Announcement . 8
5.0 Overview . 8
5.1 MBS User Service Description data model . 8
5.1.1 General . 8
5.2 Semantics . 10
5.2.1 General . 10
5.2.2 MBS User Service Bundle Description metadata unit . 10
5.2.3 MBS User Service Description metadata unit . 10
5.2.4 MBS Distribution Session Description metadata unit . 10
5.2.5 Session Description metadata unit . 11
5.2.6 MBS Application Service Description metadata unit . 11
5.2.7 MBS Schedule Description metadata unit . 12
5.2.8 MBS Object Repair Parameters metadata unit . 14
5.3 Delivery of Service Announcement . 15
6 Object Delivery Method . 15
6.1 General . 15
6.2 Usage of FLUTE for Object Distribution Method . 15
6.2.1 General . 15
6.2.2 Session Description metadata unit . 16
6.2.2.1 General . 16
6.2.2.2 MBS service type of MBS Session . 16
6.2.2.3 SDP examples for FLUTE Session . 17
6.2.3 Operating modes for Object Distribution Method . 18
6.2.3.1 Introduction . 18
6.2.3.2 Single object operating mode . 18
6.2.3.3 Object collection operating mode . 18
6.2.3.4 Object carousel operating mode . 18
6.2.3.5 Segment streaming operating mode . 18
7 Packet Delivery Method . 19
7.1 General . 19
7.2 Re-using MBMS Delivery Method as Packet Distribution Method . 19
7.2.1 General . 19
7.2.3 Session Description. 20
7.2.3.1 General . 20
7.2.3.2 SDP examples for Packet Distribution Method. 20
Annex A (normative): Syntax for Service Announcement . 22
A.1 XML-based representation . 22
A.1.1 MBS User Service Description schema . 22
A.1.2 Object Repair Parameters schema . 24
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A.1.3 Schedule Description schema . 25
A.2 JSON-based representation . 26
A.2.1 MBS User Service Announcement schema . 26
Annex B (informative): Service Announcement examples . 30
B.1 XML-based representation . 30
B.2 JSON-based representation . 30
Annex C (normative): Controlled vocabulary of conformance profiles . 32
Annex (informative): Change history . 33
History . 34

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3GPP TS 26.517 version 17.1.0 Release 17 5 ETSI TS 126 517 V17.1.0 (2023-01)
Foreword
This Technical Specification has been produced by the 3rd 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.
In the present document, modal verbs have the following meanings:
shall indicates a mandatory requirement to do something
shall not indicates an interdiction (prohibition) to do something
The constructions "shall" and "shall not" are confined to the context of normative provisions, and do not appear in
Technical Reports.
The constructions "must" and "must not" are not used as substitutes for "shall" and "shall not". Their use is avoided
insofar as possible, and they are not used in a normative context except in a direct citation from an external, referenced,
non-3GPP document, or so as to maintain continuity of style when extending or modifying the provisions of such a
referenced document.
should indicates a recommendation to do something
should not indicates a recommendation not to do something
may indicates permission to do something
need not indicates permission not to do something
The construction "may not" is ambiguous and is not used in normative elements. The unambiguous constructions
"might not" or "shall not" are used instead, depending upon the meaning intended.
can indicates that something is possible
cannot indicates that something is impossible
The constructions "can" and "cannot" are not substitutes for "may" and "need not".
will indicates that something is certain or expected to happen as a result of action taken by an agency
the behaviour of which is outside the scope of the present document
will not indicates that something is certain or expected not to happen as a result of action taken by an
agency the behaviour of which is outside the scope of the present document
might indicates a likelihood that something will happen as a result of action taken by some agency the
behaviour of which is outside the scope of the present document
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might not indicates a likelihood that something will not happen as a result of action taken by some agency
the behaviour of which is outside the scope of the present document
In addition:
is (or any other verb in the indicative mood) indicates a statement of fact
is not (or any other negative verb in the indicative mood) indicates a statement of fact
The constructions "is" and "is not" do not indicate requirements.
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3GPP TS 26.517 version 17.1.0 Release 17 7 ETSI TS 126 517 V17.1.0 (2023-01)
1 Scope
The present document defines protocols and formats for User Services as defined in TS 26.502 [6] and conveyed using
the 5G multicast–broadcast capabilities of the 5G System defined in TS 23.501 [2], TS 23.502 [3] and TS 23.247 [5].
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 23.501: "System architecture for the 5G System (5GS)".
[3] 3GPP TS 23.502: "Procedures for the 5G System (5GS)".
[4] 3GPP TS 23.503: "Policy and charging control framework for the 5G System (5GS); Stage 2".
[5] 3GPP TS 23.247: "Architectural enhancements for 5G multicast-broadcast services; Stage 2".
[6] 3GPP TS 26.502: "5G multicast–broadcast services; User Service architecture".
[7] 3GPP TS 26.346: “MBMS; Protocols and Codecs".
[8] IETF RFC 8866: "Session Description Protocol".
[9] W3C: "XML Schema Part 2: Datatypes".
[10] 3GPP TS 23.003: "Numbering, addressing and identification".
[11] 3GPP TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".
[12] IETF RFC 3926: "FLUTE - File Delivery over Unidirectional Transport".
[13] IETF RFC 2616: "Hypertext Transfer Protocol -- HTTP/1.1".
3 Definitions of terms, symbols and abbreviations
3.1 Terms
For the purposes of the present document, the terms given in 3GPP TR 21.905 [1], TS 23.501 [2], TS 23.502 [3],
TS 23.247 [5], TS 26.502 [6] and the following apply. A term defined in the present document takes precedence over
the definition of the same term, if any, in 3GPP TR 21.905 [1].
3.2 Symbols
Void.
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3.3 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1], TS 23.501 [2],
TS 23.502 [3], TS 23.247 [4] and the following apply. An abbreviation defined in the present document takes
precedence over the definition of the same abbreviation, if any, in 3GPP TR 21.905 [1].
CMAF Common Media Application Format
FLUTE File Delivery over Unidirectional Transport
MBS Multicast–Broadcast Services
MB-SMF Multicast–Broadcast Session Management Function
MB-UPF Multicast–Broadcast User Plane Function
MBSF Multicast–Broadcast Service Function
MBSTF Multicast–Broadcast Service Transport Function
PCF Policy and Charging Function
NEF Network Exposure Function
SDP Session Description Protocol
TMGI Temporary Mobile Group Identity
UE User Equipment
UML Unified Markup Language
XML eXtensible Markup Language
4 System overview
5 MBS User Service Announcement
5.0 Overview
MBS User Service Announcement is needed in order to advertise MBS User Services in advance of, and potentially
during, the MBS User Service Sessions described. MBS User Service Announcement (as defined in clauses 4.5.7
and 4.5.8 of TS 26.502 [3]) is provided by means of an MBS User Service Description, the syntax of which is defined in
this clause.
5.1 MBS User Service Description data model
5.1.1 General
An MBS User Service Description is described by a set of metadata documents that are delivered as described in
clause 4.3.2 of TS 26.502 [3]. The data model defined in this clause subdivides the parameters defined in [3] and groups
them into a set of metadata documents.
Each metadata document is divided into metadata units. A metadata unit is a single uniquely identifiable block of
metadata. The metadata itself describes details of services. An obvious example of a metadata unit would be a single
SDP document [8].
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The metadata consists of:
- An MBS User Service Bundle Description metadata unit (see clause 5.2.2) describing a bundle of one or more
MBS User Services, and containing one or more:
- MBS User Service Description metadata unit (see clause 5.2.3) describing an MBS User Service Session that
is associated with:
- One or more MBS Distribution Session Description metadata units (see clause 5.2.4), each of which
references a Session Description document [8] that may be packaged with the MBS User Service Bundle
Description, and each of which may optionally reference an Object Repair Parameters document (see
clause 5.2.7) describing the object repair parameters for the MBS Distribution Session.
- Zero or more MBS Application Service Description metadata units (see clause 5.2.5), each of which
references an Application Service Entry Point document that may be packaged with the MBS User
Service Bundle Description. Additional resources referenced by the entry point document may also be
packaged with the MBS User Service Bundle Description.
- Zero or one MBS Schedule Description metadata unit (see clause 5.2.6) advertising the delivery schedule
for the MBS User Service Session.
Figure 5.1-1 illustrates the relationships between these metadata units using UML for a single MBS User Service
Bundle.
User Service Bundle Description document
MBS User Service
MBS User Service Description
Bundle Description
1.N userServiceDescription
bundleDescription
1.N 1.N 1.N
0.N
MBS Application Service Description
appServiceDescription
1.N 0.1
MBS Distribution Session Description MBS Schedule Description
distributionSessionDescription scheduleDescription
1.N
1.N
references references
references references
1 1
0.1 1
Object Application
0.1 Session Schedule
Repair Service
Description
Description
1.N
Parameters Entry Point
document document
document document
references
0.N
Additional
resource
NOTE: “N” means any number in each instance.
Figure 5.1-1: User Service Data Model simple description
An MBS User Service Bundle Description document shall contain one or more instances of the MBS User Service
Description metadata unit, each of which describes a single MBS User Service Session within the MBS User Service
Bundle.
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Each instance of the MBS User Service Description metadata unit shall include at least one MBS Distribution Service
Description metadata unit describing the set of MBS Distribution Sessions currently associated with the MBS User
Service Session.
- The MBS Distribution Session Description metadata unit shall refer to one Session Description document.
- Each MBS Distribution Session Description metadata unit may contain a reference to an Object Repair
Parameters document.
Each instance of the MBS User Service Description metadata unit may include zero or more MBS Application Service
Description metadata units, each one referencing an Application Service Entry Point document (e.g. a DASH MPD,
HLS Master Playlist or HTML document) which describes the root of the Application Service associated with this MBS
User Service. When multiple Application Service Entry Point documents are referenced, an MBS Client shall select
only one on the basis of a distinct MIME content type indicated in the Application Service Description.
Each instance of the MBS User Service Description metadata unit may include an MBS Schedule Description metadata
unit. If included, the MBS Schedule Description shall refer to a Schedule Description document, and the UE can expect
to receive MBS User Service data during the time periods described in the Schedule Description document.
In the case of the Object Distribution Method, the Schedule Description document may include an object transmission
schedule for objects associated with the MBS User Service Session. The UE may select which objects to receive based
on the object transmission schedule information published in the Schedule Description document.
5.2 Semantics
5.2.1 General
The following description in this clause presumes XML encoding of the metadata units comprising the MBS User
Service Announcement.
5.2.2 MBS User Service Bundle Description metadata unit
The root element of the MBS User Service Bundle Description metadata unit is bundleDescription. This element is
of type bundleDescriptionType. The bundleDescription element contains one or several userServiceDescription
child elements.
5.2.3 MBS User Service Description metadata unit
The root element of the MBS User Service Description metadata unit is the userServiceDescription element. Each
userServiceDescription element shall signal a unique identifier in its @serviceId attribute and this shall be of URI
format.
The userServiceDescription element may contain one or more name child elements. The purpose of a name element
is to communicate a human-readable title of the MBS User Service. For each name element, the language shall be
specified according to XML datatypes (XML Schema Part 2 [9]).
The userServiceDescription element may contain one or more serviceLanguage child elements. Each
serviceLanguage element represents the available languages of the MBS User Service. The language shall be
specified according to XML datatypes (XML Schema Part 2 [9]) using the xml:lang attribute.
5.2.4 MBS Distribution Session Description metadata unit
Each MBS User Service Description metadata unit shall reference at least one MBS Distribution Session Description.
The distributionSessionDescription element shall contain a @conformanceProfile attribute indicating the set
of features that the MBS Distribution Session conforms to and which the MBS Client needs to support in order to fully
receive the MBS Distribution Session. The value of this attribute shall be a fully-qualified term identifier URI from the
controlled vocabulary defined in annex C.
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The distributionSessionDescription element shall contain a @sessionDescriptionURI attribute which
references a Session Description document. The element may also contain an @objectRepairParametersURI attribute
referencing an Object Repair Parameters document.
The distributionSessionDescription element may contain a @dataNetworkName attribute indicating a Data
Network Name (DNN) as defined in TS 23.003 [10]. When this attribute is present, the MBS Client shall use the given
DNN for interactions with the MBSF at reference point MBS-5 and with the MBS AS at reference point MBS-4-UC. If
this attribute is not present, the MBS UE shall use a default PDU Session for these network interactions.
The userServiceDescription element may include an availabilityInfo child element providing additional
information pertaining to the availability of the MBS Distribution Session within the 5G Network. If present, the
availabilityInfo element shall include one or more infoBinding child elements. The infoBinding element shall
contain the child elements serviceArea, mbsFSAId and radiofrequency:
- The serviceArea element declares the one or more service areas in which the MBS Session corresponding to
this MBS Distribution Session is currently available.
- In the case of a broadcast MBS Session corresponding to this MBS Distribution Session, the mbsFSAId element
identifies a preconfigured area within which, and in proximity to, the cell(s) announce the MBS FSA ID and its
associated frequency.
NOTE: This is used to guide frequency selection by the UE for a broadcast MBS Session.
- The radioFrequency element indicates the one or more radio frequencies in the NG-RAN downlink which
transmit the MBS Session corresponding to this MBS Distribution Session in the service area(s) identified by the
serviceArea element.
5.2.5 Session Description metadata unit
The @sessionDescriptionURI attribute of the MBS User Service Bundle Description references a Session
Description metadata unit. Each Session Description metadata unit shall describe one MBS Distribution Session. The
Session Description metadata unit is conveyed in a Session Description document that shall be formatted according to
RFC 8866 [8]. The Session Description document may be packaged in the same MBS User Service Bundle.
- The session description for the MBS Object Distribution Method is specified in clause 6.2.3
- The session description for the MBS Packet Distribution Method is specified in clause 7.2.3.
5.2.6 MBS Application Service Description metadata unit
In order to support application services in MBS, the MBS User Service Bundle Description metadata unit shall contain
an appServiceDescription element referencing an Application Service Entry Point document which contains the
descriptive information of the resources delivered via MBS and/or unicast distribution. That Application Service Entry
Point document shall be formatted according to the value of the @mimeType attribute.
If the MBS User Service Description contains a reference to an Application Service Entry Point document, then:
1) At least one MBS Distribution Session Description of type Object Distribution Method shall be present, i.e. the
MBS User Service Description shall include at least one distributionSessionDescription element
referencing a Session Description Document that describes an Object Distribution Method as defined in clause 7.
2) When multiple MBS Distribution Session Descriptions of type Object Distribution Method are present, the
appServiceDescription element shall define a mapping between the Application Service Entry Point
document and the associated MBS Distribution Session.
3) The MBS Distribution Session described by the Session Description document shall deliver objects that are
directly or indirectly referenced by the Application Service Entry Point document.
4) When the Application Service Entry Point document is a DASH MPD, then all of the following shall hold:
a) The MBS Distribution Session shall deliver the objects such that the last packet of the delivered object is
available to the MBS Client by no later than its availability time as announced in the DASH MPD.
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b) The Content-Location element in the FLUTE File Delivery Table for the delivered object shall match the
URL in the DASH MPD.
Editor’s Note: Bullets 4 and 5 should be moved to Clause 7.
4) If an update to the Application Service Entry Point document is delivered as a FLUTE transmission object then
the Content-Location element in the FLUTE File Delivery Table for the delivered object shall match the URL
of the referenced Application Service Entry Point document.
In the case of 3GP-DASH formatted content, the appServiceDescription element may refer to a unified media
manifest document which describes Representations available for both MBS reception and unicast retrieval, and this
shall be used by MBS Clients compliant with this specification. In practical deployments, different subsets of the
Representations described by the unified manifest document and referenced by such appServiceDescription may be
specified for:
- Availability via MBS delivery only,
- Availability via both unicast and MBS delivery,
- Availability via unicast only, and the Representation is redundant in MBS area coverage, i.e. the usage of these
resources does not provide an improved user experience. As an example, this may be a lower bitrate
Representation of a media component for which a higher bitrate is available over MBS distribution, and
- Availability always via unicast, and the Representation is supplementary in MBS area coverage, i.e. even in
MBS area coverage these resources provide an improved user experience. As an example, this may be a
secondary language that is only accessible over unicast.
All resources that are directly or indirectly referenced in the Application Service Entry Point document of this metadata
unit that are expected to be retrieved by HTTP GET shall be delivered by at least one of the MBS Distribution Sessions
associated with the MBS User Service Description.
5.2.7 MBS Schedule Description metadata unit
Availability of the Schedule Description metadata unit is indicated by the presence of the scheduleDescription
element in the MBS User Service Bundle Description metadata unit. The URI of the Schedule Description instance
document is provided by the @scheduleDescriptionURI attribute in the scheduleDescription element.
A Schedule Description instance document describes the distribution schedule of the MBS Distribution Session and the
availability of content via unicast delivery for an MBS User Service in terms of:
- Start/stop lists,
- Recurrence information,
- The service ID or service class to which the schedule may apply,
An MBS User Service containing multiple content components may be carried on a single MBS Distribution Session, or
on multiple MBS Distribution Sessions. The MBS Client can expect to receive MBS data during the described time
period(s) when at least one of the MBS Distribution Sessions for the MBS User Service is active.
A Schedule Description instance document may also include a schedule of when the objects are intended to be
transmitted as part of an MBS Distribution Session using the Object Distribution Method. The object schedule
information is defined in terms of:
- The service ID or service class to which the object schedule applies,
- An object transmission schedule listing for each object:
- Object URI,
- A list of start and end times for distribution of the object via MBS,
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A Schedule Description instance document may be delivered to the MBS Client:
- prior to the MBS Distribution Session as part of the MBS User Service Announcement along with the Session
Description metadata unit (out-of-band of that session); or
- in band within an MBS Distribution Session; or
- via an MBS Distribution Session dedicated to the transport of Schedule Description instance documents.
The most recently delivered Schedule Description instance document shall take priority, such that schedule parameters
received prior to – and out-of-band of – the MBS Distribution Session they apply to are regarded as "initial defaults",
and schedule parameters received in-band with the MBS Distribution Session overwrite the earlier received schedule
parameters.
The Schedule Description instance document is clearly identified using a URI, to enable cross-referencing by the MBS
Client of instance documents delivered in band and out of band.
The session schedule and object transmission schedule are described in the Schedule Description instance document
respectively by the sessionSchedule and objectSchedule elements.
- The start and stop time of a single sessionSchedule is specified by the start and stop elements.
- The start and stop time of a single objectSchedule is specified by the @start and @end attributes.
In both cases the time is specified as the absolute date and UTC time. The duration may be determined by subtracting
the start time from the stop time.
The MBS Distribution Session shall be available to the MBS Client during the time interval(s) announced by the
session schedule (i.e. scheduleDescription/serviceSchedule/sessionSchedule element of the Schedule
Description instance document), for either unicast or MBS reception. In particular, for unicast reception, the Schedule
Description is indicative of the time availability for unicast access of an MBS User Service while the TMGI for the
MBS Distribution Session is not activated, as well as for unicast fallback reception when the MBS Client is not located
in the MBS coverage area for the service.
The MBS Client may activate reception of that MBS Distribution Session only within the sessionSchedule (and the
objectSchedule if present) time window.
When an objectSchedule element is present in a serviceSchedule element, then:
- The MBS Client should not expect that an object described by an objectSchedule will be updated during a
time window instance, defined by @start and @end attributes, within a deliveryInfo element of that
objectSchedule.
- There shall be only one object version (as defined in the @File-ETag attribute in the FLUTE File Delivery
Table) transmitted in a time window defined by the @start and @end attributes within a deliveryInfo element
objectSchedule element.
for a given
- If objectETag attribute is not present, the objects transmitted in the time windows from different
deliveryInfo elements in an objectSchedule should not be expected to be the same object version.
- If the @objectETag attribute is present, there shall be only one object version transmitted in all of the time
windows delimited by the start and end attributes of each of the one or more deliveryInfo elements.
- In-band Schedule Description instance document updates can be used to provide a dynamic schedule update to
override the existing delivery schedule, such as using the @cancelled attribute mechanism specified in this
clause.
- A sessionSchedule element in the same serviceSchedule element shall be present, and its start and stop
elements shall specify a time window that completely overlaps the time windows specified in each of the
objectSchedule elements of the same serviceSchedule.
sessionSchedule is present and there are no objectSchedule child elements in a serviceSchedule, then
When a
the MBS Client should download each new object, independently of whether the MBS Distribution Session uses the
MBS Object Distribution Method or the MBS Packet Distribution Method.
ETSI
3GPP TS 26.517 version 17.1.0 Release 17 14 ETSI TS 126 517 V17.1.0 (2023-01)
The objectSchedule element specifies details about the objects to be delivered during an MBS Distribution Session.
The @sessionId attribute, if present, identifies the MBS Distribution Session for each object. If not present, an MBS
Client shall instead determine the MBS Distribution Session by examining the Session Description metadata unit for the
MBS Distribution Session. The @objectETag attribute of the objectSchedule element is the version identifier of the
object. If present, the purpose of this entity tag is to enable an MBS Client to determine if an object has changed since a
prior reception without having to download the object.
The scheduleUpdate element specifies a time after which MBS Client shall seek to update its schedule information by
acquiring the latest available Schedule Description instance document.
An @index attribute is included as a child of the sessionSchedule element. If the sessionSchedule does not
describe any session reoccurrence, then the index corresponds to the single session occurrence. If the
sessionSchedule describes one or more reoccurrences the @index is the starting index of the first session occurrence
with the index value increased by one for each session reoccurrence.
A @cancelled attribute is defined as a child of the objectSchedule/objectURI element.
- If the @cancelled attribute is set to "true" or "1", then the transmission of the object identified by the
objectURI element is cancelled, and the MBS Client shall cancel any applicable repair and/or reception
reporting procedures for that object.
If this object schedule-level cancellation indication in the updated schedule description is received after the
associated object has already been delivered, then any related repair or reception reporting for that object
(associated with its parent service), either in progress or yet to occur, shall be aborted.
- If the @cancelled attribute is set to "false" or "0" or is absent, then normal object transmission and associated
delivery procedures, if applicable, shall occur.
A sessionScheduleOverride element is defined as a child of the serviceSchedule element. If present, the
sessionScheduleOverride element indicates either the cancellation of the session occurrence, or schedule override,
as follows:
- If the @cancelled attribute (a child of sessionScheduleOverride element) is set to "true" or "1", then the
transmission of the MBS Distribution Session identified by the index attribute (a child of
sessionScheduleOverride element) is cancelled, and the MBS Client shall cancel any applicable repair and/or
reception reporting for all objects belonging to that MBS Distribution Session.
If this session schedule-level cancellation indication in the updated schedule description is received after any of
the associated objects have already been delivered, then any related repair or reception reporting for those
objects (associated with their parent service(s)), either in progress or yet to occur, shall be aborted.
- If the @cancelled attribute (a child of sessionScheduleOverride element) is set to "false" or "0" or is absent,
then the start and
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