| Internet-Draft | MoQ qlog event definitions | March 2025 |
| Pardue & Engelbart | Expires 4 September 2025 | [Page] |
This document defines a qlog event schema containing concrete events for MoQ.¶
This note is to be removed before publishing as an RFC.¶
The latest revision of this draft can be found at https://LPardue.github.io/draft-pardue-moq-qlog-moq-events/draft-pardue-moq-qlog-moq-events.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-pardue-moq-qlog-moq-events/.¶
Discussion of this document takes place on the Media Over QUIC mailing list (mailto:moq@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/moq/. Subscribe at https://www.ietf.org/mailman/listinfo/moq/.¶
Source for this draft and an issue tracker can be found at https://github.com/LPardue/draft-pardue-moq-qlog-moq-events.¶
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This document defines a qlog event schema (Section 8 of [QLOG-MAIN]) containing concrete events for Media over QUIC Transport [MOQT].¶
The event namespace with identifier moqt is defined; see Section 3. In
this namespace multiple events derive from the qlog abstract Event class
(Section 7 of [QLOG-MAIN]), each extending the "data" field and defining
their "name" field values and semantics.¶
Table 1 summarizes the name value of each event type that is defined in this specification. Some event data fields use complex data types. These are represented as enums or re-usable definitions, which are grouped together on the bottom of this document for clarity.¶
| Name value | Importance | Definition |
|---|---|---|
| moqt:control_message_created | Core | Section 4.1 |
| moqt:control_message_parsed | Core | Section 4.2 |
| moqt:stream_type_set | Core | Section 4.3 |
| moqt:object_datagram_created | Core | Section 4.4 |
| moqt:object_datagram_parsed | Core | Section 4.5 |
| moqt:object_datagram_status_created | Core | Section 4.6 |
| moqt:object_datagram_status_parsed | Core | Section 4.7 |
| moqt:subgroup_header_created | Core | Section 4.8 |
| moqt:subgroup_header_parsed | Core | Section 4.9 |
| moqt:subgroup_object_created | Core | Section 4.10 |
| moqt:subgroup_object_parsed | Core | Section 4.11 |
| moqt:fetch_header_created | Core | Section 4.12 |
| moqt:fetch_header_parsed | Core | Section 4.13 |
| moqt:fetch_object_created | Core | Section 4.14 |
| moqt:fetch_object_parsed | Core | Section 4.15 |
When any event from this document is included in a qlog trace, the "protocol_types" qlog array field MUST contain an entry with the value "MOQT":¶
$ProtocolType /= "MOQT"
The events described in this document can be used with or without logging the related QUIC events defined in [QLOG-QUIC]. If used with QUIC events, the QUIC document takes precedence in terms of recommended filenames and trace separation setups.¶
If used without QUIC events, it is recommended that the implementation assign a globally unique identifier to each MOQT session. This ID can then be used as the value of the qlog "group_id" field, as well as the qlog filename or file identifier, potentially suffixed by the vantagepoint type (For example, abcd1234_server.qlog would contain the server-side trace of the connection with GUID abcd1234).¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
The event and data structure definitions in ths document are expressed in the Concise Data Definition Language [CDDL] and its extensions described in [QLOG-MAIN].¶
The following fields from [QLOG-MAIN] are imported and used: name, namespace, type, data, group_id, protocol_types, importance, RawInfo, and time-related fields.¶
As is the case for [QLOG-MAIN], the qlog schema definitions in this document are intentionally agnostic to serialization formats. The choice of format is an implementation decision.¶
This document describes how the MOQT protocol is expressed in qlog with an event
schema. Per the requirements in Section 8 of [QLOG-MAIN], this document
registers the moqt namespace. The event schema URI is
urn:ietf:params:qlog:events:moqt.¶
This section is to be removed before publishing as an RFC.¶
Only implementations of the final, published RFC can use the events belonging to
the event schema with the URI urn:ietf:params:qlog:events:moqt. Until such an
RFC exists, implementations MUST NOT identify themselves using this URI.¶
Implementations of draft versions of the event schema MUST append the string
"-" and the corresponding draft number to the URI. For example, draft 99 of this
document is identified using the URI urn:ietf:params:qlog:events:moqt-99.¶
The namespace identifier itself is not affected by this requirement.¶
MOQT events extend the $ProtocolEventData extension point defined in
[QLOG-MAIN]. Additionally, they allow for direct extensibility by their use of
per-event extension points via the $$ CDDL "group socket" syntax, as also
described in [QLOG-MAIN].¶
MOQTEventData = MOQTControlMessageCreated /
MOQTControlMessageParsed /
MOQTStreamTypeSet /
MOQTObjectDatagramCreated /
MOQTObjectDatagramParsed /
MOQTObjectDatagramStatusCreated /
MOQTObjectDatagramStatusParsed /
MOQTSubgroupHeaderCreated /
MOQTSubgroupHeaderParsed /
MOQTSubgroupObjectCreated /
MOQTSubgroupObjectParsed /
MOQTFetchHeaderCreated /
MOQTFetchHeaderParsed /
MOQTFetchObjectCreated /
MOQTFetchObjectParsed
$ProtocolEventData /= MOQTEventData
MOQT events are logged when a certain condition happens at the application layer, and there isn't always a one to one mapping between HTTP and QUIC events. The exchange of data between the HTTP and QUIC layer is logged via the "stream_data_moved" and "datagram_data_moved" events in [QLOG-QUIC].¶
The concrete MOQT event types are further defined below, their type identifier is the heading name.¶
Some MOQT messages include a reason phrase that can provide additional
information in the format of a byte sequences. However, these sequences are not
guaranteed to be presentable as UTF-8. In order to accomodate various encodings,
where the wire image of a message includes a reason phrase, the MOQT qlog event
type, includes two option fields: reason (for UTF-8) and reason_bytes (a
hex-encoded string representing raw bytes). Implementations SHOULD log at least
one format, but MAY log both or none.¶
The control_message_created event is emitted when a control message is created.
It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
The definition of control message content is in Section 5.3.¶
MOQTControlMessageCreated = {
stream_id: uint64
? length: uint64
message: $MOQTControlMessage
? raw: RawInfo
* $$moqt-controlmessagecreated-extension
}
The control_message_parsed event is emitted when a control message is parsed.
It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
The definition of control message content is in Section 5.3.¶
MOQTControlMessageParsed = {
stream_id: uint64
? length: uint64
message: $MOQTControlMessage
? raw: RawInfo
* $$moqt-controlmessageparsed-extension
}
The stream_type_set event conveys when a MOQT stream type becomes known. It
has Base importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTStreamTypeSet = {
? owner: Owner
stream_id: uint64
stream_type: $MOQTStreamType
* $$moqt-streamtypeset-extension
}
$MOQTStreamType /= "subgroup_header" /
"fetch_header"
The object_datagram_created event is emitted when the OBJECT_DATAGRAM message
is created. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTObjectDatagramCreated = {
track_alias: uint64
group_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
? object_payload: RawInfo
* $$moqt-objectdatagramcreated-extension
}
The object_datagram_parsed event is emitted when the OBJECT_DATAGRAM message
is parsed. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTObjectDatagramParsed = {
track_alias: uint64
group_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
? object_payload: RawInfo
* $$moqt-objectdatagramparsed-extension
}
The object_datagram_status_created event is emitted when the
OBJECT_DATAGRAM_STATUS message is created. It has Core importance level; see
Section 9.2 of [QLOG-MAIN].¶
MOQTObjectDatagramStatusCreated = {
track_alias: uint64
group_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_status: uint64
* $$moqt-objectdatagramstatuscreated-extension
}
The object_datagram_status_parsed event is emitted when the
OBJECT_DATAGRAM_STATUS message is parsed. It has Core importance level; see
Section 9.2 of [QLOG-MAIN].¶
MOQTObjectDatagramStatusParsed = {
track_alias: uint64
group_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_status: uint64
* $$moqt-objectdatagramstatusparsed-extension
}
The subgroup_header_created event is emitted when a stream begins and a
SUBGROUP_HEADER is created. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTSubgroupHeaderCreated = {
stream_id: uint64
track_alias: uint64
group_id: uint64
subgroup_id: uint64
publisher_priority: uint8
* $$moqt-subgroupheadercreated-extension
}
The subgroup_header_parsed event is emitted when the SUBGROUP_HEADER is
parsed. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTSubgroupHeaderParsed = {
stream_id: uint64
track_alias: uint64
group_id: uint64
subgroup_id: uint64
publisher_priority: uint8
* $$moqt-subgroupheaderparsed-extension
}
The subgroup_object_created event is emitted when a subgroup object is
created. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTSubgroupObjectCreated = {
stream_id: uint64
? group_id: uint64
? subgroup_id: uint64
object_id: uint64
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_payload_length: uint64
? object_status: uint64
? object_payload: RawInfo
* $$moqt-subgroupobjectcreated-extension
}
The subgroup_object_parsed event is emitted when a subgroup object is parsed.
It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTSubgroupObjectParsed = {
stream_id: uint64
? group_id: uint64
? subgroup_id: uint64
object_id: uint64
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_payload_length: uint64
? object_status: uint64
? object_payload: RawInfo
* $$moqt-subgroupobjectparsed-extension
}
The fetch_header_created event is emitted when a stream begins and a
FETCH_HEADER is created. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTFetchHeaderCreated = {
stream_id: uint64
subscribe_id: uint64
* $$moqt-fetchheadercreated-extension
}
The fetch_header_parsed event is emitted when the SUBGROUP_HEADER is
parsed. It has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTFetchHeaderParsed = {
stream_id: uint64
subscribe_id: uint64
* $$moqt-fetchheaderparsed-extension
}
The fetch_object_created event is emitted when a fetch object is created. It
has Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTFetchObjectCreated = {
stream_id: uint64
group_id: uint64
subgroup_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_payload_length: uint64
? object_status: uint64
? object_payload: RawInfo
* $$moqt-fetchobjectcreated-extension
}
The fetch_object_parsed event is emitted when a fetch object is parsed. It has
Core importance level; see Section 9.2 of [QLOG-MAIN].¶
MOQTFetchObjectParsed = {
stream_id: uint64
group_id: uint64
subgroup_id: uint64
object_id: uint64
publisher_priority: uint8
extension_headers_length: uint64
? extension_headers: [* MOQTExtensionHeader]
object_payload_length: uint64
? object_status: uint64
? object_payload: RawInfo
* $$moqt-fetchobjectparsed-extension
}
The following data type definitions can be used in MOQT events.¶
Owner = "local" /
"remote"
MOQTParameter = {
name: $MOQTParameterName
length: uint64
? value: RawInfo
}
$MOQTParameterName /= "authorization_info" /
"delivery_timeout" /
"max_cache_duration" /
"path" /
"max_subscribe_id"
The generic $MOQTControlMessage is defined here as a CDDL "type socket" extension point.
It can be extended to support additional MOQT control message types.¶
; The MOQTControlMessage is any key-value map (e.g., JSON object)
$MOQTControlMessage /= {
* text => any
}
The MOQT control message types defined in this document are as follows:¶
MOQTBaseControlMessages = MOQTClientSetupMessage /
MOQTServerSetupMessage /
MOQTGoaway /
MOQTSubscribe /
MOQTSubscribeUpdate /
MOQTUnsubscribe /
MOQTFetch /
MOQTFetchCancel /
MOQTAnnounceOk /
MOQTAnnounceError /
MOQTAnnounceCancel /
MOQTTrackStatusRequest /
MOQTSubscribeAnnounces /
MOQTUnsubscribeAnnounces /
MOQTSubscribeOk /
MOQTSubscribeError /
MOQTFetchOk /
MOQTFetchError /
MOQTSubscribeDone /
MOQTMaxSubscribeId /
MOQTSubscribesBlocked /
MOQTAnnounce /
MOQTUnannounce /
MOQTTrackStatus /
MOQTSubscribeAnnouncesOk /
MOQTSubscribeAnnouncesError
$MOQTControlMessage /= MOQTBaseControlMessages
MOQTClientSetupMessage = {
type: "client_setup"
number_of_support_versions: uint64
supported_versions: [* uint64]
number_of_parameters: uint64
setup_parameters: [* MOQTParameter]
}
MOQTServerSetupMessage = {
type: "server_setup"
selected_version: uint64
number_of_parameters: uint64
setup_parameters: [* MOQTParameter]
}
MOQTGoaway = {
type: "goaway"
? length: uint64
new_session_uri: RawInfo
}
MOQTSubscribe = {
type: "subscribe"
subscribe_id: uint64
track_alias: uint64
; track_namespace: TODO pending tuple decision
track_name: RawInfo
subscriber_priority: uint8
group_order: uint8
filter_type: uint64
? start_group: uint64
? start_object: uint64
? end_group: uint64
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTSubscribeUpdate = {
type: "subscribe_update"
subscribe_id: uint64
start_group: uint64
start_object: uint64
end_group: uint64
subscriber_priority: uint8
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTUnsubscribe = {
type: "unsubscribe"
subscribe_id: uint64
}
MOQTFetch = {
type: "fetch"
subscribe_id: uint64
subscriber_priority: uint8
group_order: uint8
fetch_type: uint64
; ? track_namespace: TODO pending tuple decision
? track_name: RawInfo
? start_group: uint64
? start_object: uint64
? end_group: uint64
? end_object: uint64
? joining_subscribe_id: uint64
? preceding_group_offset: uint64
number_of_parameters: uint64
parameters: [* MOQTParameter]
}
MOQTFetchCancel = {
type: "fetch_cancel"
subscribe_id: uint64
}
MOQTAnnounceOk = {
type: "announce_ok"
; track_namespace: TODO pending tuple decision
}
MOQTAnnounceError = {
type: "announce_error"
; track_namespace: TODO pending tuple decision
error_code: uint64
? reason: text
? reason_bytes: hexstring
}
MOQTAnnounceCancel = {
type: "announce_cancel"
; track_namespace: TODO pending tuple decision
error_code: uint64
? reason: text
? reason_bytes: hexstring
}
MOQTTrackStatusRequest = {
type: "track_status_request"
; track_namespace: TODO pending tuple decision
track_name: RawInfo
}
MOQTSubscribeAnnounces = {
type: "subscribe_announces"
; track_namespace: TODO pending tuple decision
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTUnsubscribeAnnounces = {
type: "subscribe_announces"
; track_namespace: TODO pending tuple decision
}
MOQTSubscribeOk = {
type: "subscribe_ok"
subscribe_id: uint64
expires: uint64
group_order: uint8
content_exists: uint8
? largest_group_id: uint64
? largest_object_id: uint64
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTSubscribeError = {
type: "subscribe_error"
subscribe_id: uint64
error_code: uint64
? reason: text
? reason_bytes: hexstring
track_alias: uint64
}
MOQTFetchOk = {
type: "fetch_ok"
subscribe_id: uint64
group_order: uint8
end_of_track: uint8
largest_group_id: uint64
largest_object_id: uint64
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTFetchError = {
type: "fetch_error"
subscribe_id: uint64
error_code: uint64
? reason: text
? reason_bytes: hexstring
}
MOQTSubscribeDone = {
type: "subscribe_done"
subscribe_id: uint64
status_code: uint64
stream_count: uint64
? reason: text
? reason_bytes: hexstring
}
MOQTMaxSubscribeId = {
type: "max_subscribe_id"
subscribe_id: uint64
}
MOQTSubscribesBlocked = {
type: "subscribes_blocked"
maximum_subscribe_id: uint64
}
MOQTAnnounce = {
type: "announce"
; track_namespace: TODO pending tuple decision
number_of_parameters: uint64
subscribe_parameters: [* MOQTParameter]
}
MOQTUnannounce = {
type: "unannounce"
; track_namespace: TODO pending tuple decision
}
MOQTTrackStatus = {
type: "track_status"
; track_namespace: TODO pending tuple decision
track_name: RawInfo
status_code: uint64
last_group_id: uint64
last_object_id: uint64
}
MOQTSubscribeAnnouncesOk = {
type: "subscribe_announces_ok"
; track_namespace: TODO pending tuple decision
}
MOQTSubscribeAnnouncesError = {
type: "subscribe_announces_error"
; track_namespace: TODO pending tuple decision
error_code: uint64
? reason: text
? reason_bytes: hexstring
}
MOQTExtensionHeader = {
header_type: uint64
? header_value: uint64
? header_length: uint64
? payload: RawInfo
}
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