HTTP/3 and QPACK qlog event definitions

Internet-Draft	HTTP/3 and QPACK qlog event definitions	February 2023
Marx, et al.	Expires 17 August 2023	[Page]

Abstract

This document describes concrete qlog event definitions and their metadata for HTTP/3 and QPACK-related events. These events can then be embedded in the higher level schema defined in [QLOG-MAIN].¶

1. Introduction

This document describes the values of the qlog name ("category" + "event") and "data" fields and their semantics for HTTP/3 [HTTP/3] and QPACK [QPACK].¶

Note to RFC editor: Please remove the follow paragraphs in this section before publication.¶

Feedback and discussion are welcome at https://github.com/quicwg/qlog. Readers are advised to refer to the "editor's draft" at that URL for an up-to-date version of this document.¶

Concrete examples of integrations of this schema in various programming languages can be found at https://github.com/quiclog/qlog/.¶

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, category, type, data, group_id, protocol_type, importance, RawInfo, and time-related fields.¶

2. Overview

This document describes how the HTTP/3 and QPACK can be expressed in qlog using the schema defined in [QLOG-MAIN]. HTTP/3 and QPACK events are defined with a category, a name (the concatenation of "category" and "event"), an "importance", an optional "trigger", and "data" fields.¶

Some data fields use complex datastructures. These are represented as enums or re-usable definitions, which are grouped together on the bottom of this document for clarity.¶

When any event from this document is included in a qlog trace, the "protocol_type" qlog array field MUST contain an entry with the value "HTTP3".¶

2.1. Usage with QUIC

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 HTTP/3 connection. 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).¶

Table 1: HTTP/3 and QPACK Events
Name value	Importance	Definition
http:parameters_set	Base	Section 4.1
http:parameters_restored	Base	Section 4.2
http:stream_type_set	Base	Section 4.3
http:frame_created	Core	Section 4.4
http:frame_parsed	Core	Section 4.5
http:push_resolved	Extra	Section 4.6
qpack:state_updated	Base	Section 6.1
qpack:stream_state_updated	Core	Section 6.2
qpack:dynamic_table_updated	Extra	Section 6.3
qpack:headers_encoded	Base	Section 6.4
qpack:headers_decoded	Base	Section 6.5
qpack:instruction_created	Base	Section 6.6
qpack:instruction_parsed	Base	Section 6.7

4. HTTP/3 Events

HTTP/3 events extend the $ProtocolEventBody extension point defined in [QLOG-MAIN].¶

HTTPEvents = HTTPParametersSet / HTTPParametersRestored /
             HTTPStreamTypeSet / HTTPFrameCreated /
             HTTPFrameParsed / HTTPPushResolved

$ProtocolEventBody /= HTTPEvents

Figure 1: HTTPEvents definition and ProtocolEventBody extension

4.1. parameters_set

Importance: Base¶

This event contains HTTP/3 and QPACK-level settings, mostly those received from the HTTP/3 SETTINGS frame. All these parameters are typically set once and never change. However, they are typically set at different times during the connection, so there can be several instances of this event with different fields set.¶

Note that some settings have two variations (one set locally, one requested by the remote peer). This is reflected in the "owner" field. As such, this field MUST be correct for all settings included a single event instance. If you need to log settings from two sides, you MUST emit two separate event instances.¶

Note: The CDDL unwrap operator (~) makes HTTPParameters into a re-usable list of fields. The unwrap operator copies the fields from the referenced type into the target type directly, extending the target with the unwrapped fields. TODO: explain this better + provide reference and maybe an example.¶

Definition:¶

HTTPParametersSet = {
    ? owner: Owner

    ~HTTPParameters

    ; qlog-specific
    ; indicates whether this implementation waits for a SETTINGS
    ; frame before processing requests
    ? waits_for_settings: bool
}

HTTPParameters = {
    ? max_field_section_size: uint64
    ? max_table_capacity: uint64
    ? blocked_streams_count: uint64

    ; additional settings for grease and extensions
    * text => uint64
}

Figure 2: HTTPParametersSet definition

Note: enabling server push is not explicitly done in HTTP/3 by use of a setting or parameter. Instead, it is communicated by use of the MAX_PUSH_ID frame, which should be logged using the frame_created and frame_parsed events below.¶

Additionally, this event can contain any number of unspecified fields. This is to reflect setting of for example unknown (greased) settings or parameters of (proprietary) extensions.¶

4.2. parameters_restored

Importance: Base¶

When using QUIC 0-RTT, HTTP/3 clients are expected to remember and reuse the server's SETTINGs from the previous connection. This event is used to indicate which HTTP/3 settings were restored and to which values when utilizing 0-RTT.¶

Definition:¶

HTTPParametersRestored = {

    ~HTTPParameters

}

Figure 3: HTTPParametersRestored definition

Note that, like for parameters_set above, this event can contain any number of unspecified fields to allow for additional and custom settings.¶

4.3. stream_type_set

Importance: Base¶

Emitted when a stream's type becomes known. This is typically when a stream is opened and the stream's type indicator is sent or received.¶

The stream_type_value field is the numerical value without VLIE encoding.¶

Definition:¶

HTTPStreamTypeSet = {
    ? owner: Owner
    stream_id: uint64

    stream_type: HTTPStreamType

    ; only when stream_type === "unknown"
    ? stream_type_value: uint64

    ; only when stream_type === "push"
    ? associated_push_id: uint64
}

HTTPStreamType =  "request" /
                  "control" /
                  "push" /
                  "reserved" /
                  "unknown" /
                  "qpack_encode" /
                  "qpack_decode"

Figure 4: HTTPStreamTypeSet definition

4.4. frame_created

Importance: Core¶

This event is emitted when the HTTP/3 framing actually happens. This does not necessarily coincide with HTTP/3 data getting passed to the QUIC layer. For that, see the "data_moved" event in [QLOG-QUIC].¶

Definition:¶

HTTPFrameCreated = {
    stream_id: uint64
    ? length: uint64
    frame: $HTTPFrame
    ? raw: RawInfo
}

Figure 5: HTTPFrameCreated definition

Note: in HTTP/3, DATA frames can have arbitrarily large lengths to reduce frame header overhead. As such, DATA frames can span many QUIC packets and can be created in a streaming fashion. In this case, the frame_created event is emitted once for the frame header, and further streamed data is indicated using the data_moved event.¶

4.5. frame_parsed

Importance: Core¶

This event is emitted when the HTTP/3 frame is parsed. Note: this is not necessarily the same as when the HTTP/3 data is actually received on the QUIC layer. For that, see the "data_moved" event in [QLOG-QUIC].¶

Definition:¶

HTTPFrameParsed = {
    stream_id: uint64
    ? length: uint64
    frame: $HTTPFrame
    ? raw: RawInfo
}

Figure 6: HTTPFrameParsed definition

HTTP/3 DATA frames can have arbitrarily large lengths to reduce frame header overhead. As such, DATA frames can span multiple QUIC packets. In this case, the frame_parsed event is emitted once for the frame header, and further streamed data is indicated using the data_moved event.¶

4.6. push_resolved

Importance: Extra¶

This event is emitted when a pushed resource is successfully claimed (used) or, conversely, abandoned (rejected) by the application on top of HTTP/3 (e.g., the web browser). This event is added to help debug problems with unexpected PUSH behaviour, which is commonplace with HTTP/2.¶

Definition:¶

HTTPPushResolved = {
    ? push_id: uint64

    ; in case this is logged from a place that does not have access
    ; to the push_id
    ? stream_id: uint64

    decision: HTTPPushDecision
}

HTTPPushDecision = "claimed" / "abandoned"

Figure 7: HTTPPushResolved definition

5. HTTP/3 Data Field Definitions

The following data field definitions can be used in HTTP/3 events.¶

5.1. Owner

Owner = "local" / "remote"

Figure 8: Owner definition

5.2. HTTPFrame

The generic $HTTPFrame is defined here as a CDDL extension point (a "socket" or "plug"). It can be extended to support additional HTTP/3 frame types.¶

; The HTTPFrame is any key-value map (e.g., JSON object)
$HTTPFrame /= {
    * text => any
}

Figure 9: HTTPFrame plug definition

The HTTP/3 frame types defined in this document are as follows:¶

HTTPBaseFrames =  HTTPDataFrame /
             HTTPHeadersFrame /
             HTTPCancelPushFrame /
             HTTPSettingsFrame /
             HTTPPushPromiseFrame /
             HTTPGoawayFrame /
             HTTPMaxPushIDFrame /
             HTTPReservedFrame /
             HTTPUnknownFrame

$HTTPFrame /= HTTPBaseFrames

Figure 10: HTTPBaseFrames definition

5.2.1. HTTPDataFrame

HTTPDataFrame = {
    frame_type: "data"
    ? raw: RawInfo
}

Figure 11: HTTPDataFrame definition

5.2.2. HTTPHeadersFrame

This represents an uncompressed, plaintext HTTP Headers frame (e.g., no QPACK compression is applied).¶

For example:¶

headers: [
  {
    "name": ":path",
    "value": "/"
  },
  {
    "name": ":method",
    "value": "GET"
  },
  {
    "name": ":authority",
    "value": "127.0.0.1:4433"
  },
  {
    "name": ":scheme",
    "value": "https"
  }
]

Figure 12: HTTPHeadersFrame example

HTTPHeadersFrame = {
    frame_type: "headers"
    headers: [* HTTPField]
}

Figure 13: HTTPHeadersFrame definition

HTTPField = {
    name: text
    value: text
}

Figure 14: HTTPField definition

5.2.3. HTTPCancelPushFrame

HTTPCancelPushFrame = {
    frame_type: "cancel_push"
    push_id: uint64
}

Figure 15: HTTPCancelPushFrame definition

5.2.4. HTTPSettingsFrame

HTTPSettingsFrame = {
    frame_type: "settings"
    settings: [* HTTPSetting]
}

HTTPSetting = {
    name: text
    value: uint64
}

Figure 16: HTTPSettingsFrame definition

5.2.5. HTTPPushPromiseFrame

HTTPPushPromiseFrame = {
    frame_type: "push_promise"
    push_id: uint64
    headers: [* HTTPField]
}

Figure 17: HTTPPushPromiseFrame definition

5.2.6. HTTPGoAwayFrame

HTTPGoawayFrame = {
    frame_type: "goaway"

    ; Either stream_id or push_id.
    ; This is implicit from the sender of the frame
    id: uint64
}

Figure 18: HTTPGoawayFrame definition

5.2.7. HTTPMaxPushIDFrame

HTTPMaxPushIDFrame = {
    frame_type: "max_push_id"
    push_id: uint64
}

Figure 19: HTTPMaxPushIDFrame definition

5.2.8. HTTPReservedFrame

HTTPReservedFrame = {
    frame_type: "reserved"

    ? length: uint64
}

Figure 20: HTTPReservedFrame definition

5.2.9. HTTPUnknownFrame

The frame_type_value field is the numerical value without VLIE encoding.¶

HTTPUnknownFrame = {
    frame_type: "unknown"
    frame_type_value: uint64
    ? raw: RawInfo
}

Figure 21: UnknownFrame definition

5.2.10. HTTPApplicationError

HTTPApplicationError =  "http_no_error" /
                        "http_general_protocol_error" /
                        "http_internal_error" /
                        "http_stream_creation_error" /
                        "http_closed_critical_stream" /
                        "http_frame_unexpected" /
                        "http_frame_error" /
                        "http_excessive_load" /
                        "http_id_error" /
                        "http_settings_error" /
                        "http_missing_settings" /
                        "http_request_rejected" /
                        "http_request_cancelled" /
                        "http_request_incomplete" /
                        "http_early_response" /
                        "http_connect_error" /
                        "http_version_fallback"

Figure 22: HTTPApplicationError definition

The HTTPApplicationError defines the general $ApplicationError definition in the qlog QUIC definition, see [QLOG-QUIC].¶

; ensure HTTP errors are properly validate in QUIC events as well
; e.g., QUIC's ConnectionClose Frame
$ApplicationError /= HTTPApplicationError

6. QPACK Events

QPACK events extend the $ProtocolEventBody extension point defined in [QLOG-MAIN].¶

QPACKEvents = QPACKStateUpdate / QPACKStreamStateUpdate /
              QPACKDynamicTableUpdate / QPACKHeadersEncoded /
              QPACKHeadersDecoded / QPACKInstructionCreated /
              QPACKInstructionParsed

$ProtocolEventBody /= QPACKEvents

Figure 23: QPACKEvents definition and ProtocolEventBody extension

QPACK events mainly serve as an aid to debug low-level QPACK issues.The higher-level, plaintext header values SHOULD (also) be logged in the http.frame_created and http.frame_parsed event data (instead).¶

Note: qpack does not have its own parameters_set event. This was merged with http.parameters_set for brevity, since qpack is a required extension for HTTP/3 anyway. Other HTTP/3 extensions MAY also log their SETTINGS fields in http.parameters_set or MAY define their own events.¶

6.1. state_updated

Importance: Base¶

This event is emitted when one or more of the internal QPACK variables changes value. Note that some variables have two variations (one set locally, one requested by the remote peer). This is reflected in the "owner" field. As such, this field MUST be correct for all variables included a single event instance. If you need to log settings from two sides, you MUST emit two separate event instances.¶

Definition:¶

QPACKStateUpdate = {
    owner: Owner
    ? dynamic_table_capacity: uint64

    ; effective current size, sum of all the entries
    ? dynamic_table_size: uint64
    ? known_received_count: uint64
    ? current_insert_count: uint64
}

Figure 24: QPACKStateUpdate definition

6.2. stream_state_updated

Importance: Core¶

This event is emitted when a stream becomes blocked or unblocked by header decoding requests or QPACK instructions.¶

Note: This event is of "Core" importance, as it might have a large impact on HTTP/3's observed performance.¶

Definition:¶

QPACKStreamStateUpdate = {
    stream_id: uint64
    ; streams are assumed to start "unblocked"
    ; until they become "blocked"
    state: QPACKStreamState
}

QPACKStreamState = "blocked" / "unblocked"

Figure 25: QPACKStreamStateUpdate definition

6.3. dynamic_table_updated

Importance: Extra¶

This event is emitted when one or more entries are inserted or evicted from QPACK's dynamic table.¶

Definition:¶

QPACKDynamicTableUpdate = {
    ; local = the encoder's dynamic table
    ; remote = the decoder's dynamic table
    owner: Owner

    update_type: QPACKDynamicTableUpdateType
    entries: [+ QPACKDynamicTableEntry]
}

QPACKDynamicTableUpdateType = "inserted" / "evicted"

QPACKDynamicTableEntry = {
    index: uint64
    ? name: text / hexstring
    ? value: text / hexstring
}

Figure 26: QPACKDynamicTableUpdate definition

6.4. headers_encoded

Importance: Base¶

This event is emitted when an uncompressed header block is encoded successfully.¶

Note: this event has overlap with http.frame_created for the HeadersFrame type. When outputting both events, implementers MAY omit the "headers" field in this event.¶

Definition:¶

QPACKHeadersEncoded = {
    ? stream_id: uint64
    ? headers: [+ HTTPField]

    block_prefix: QPACKHeaderBlockPrefix
    header_block: [+ QPACKHeaderBlockRepresentation]

    ? raw: RawInfo
}

Figure 27: QPACKHeadersEncoded definition

6.5. headers_decoded

Importance: Base¶

This event is emitted when a compressed header block is decoded successfully.¶

Note: this event has overlap with http.frame_parsed for the HeadersFrame type. When outputting both events, implementers MAY omit the "headers" field in this event.¶

Definition:¶

QPACKHeadersDecoded = {
    ? stream_id: uint64
    ? headers: [+ HTTPField]

    block_prefix: QPACKHeaderBlockPrefix
    header_block: [+ QPACKHeaderBlockRepresentation]

    ? raw: RawInfo
}

Figure 28: QPACKHeadersDecoded definition

6.6. instruction_created

Importance: Base¶

This event is emitted when a QPACK instruction (both decoder and encoder) is created and added to the encoder/decoder stream.¶

Definition:¶

QPACKInstructionCreated = {
    ; see definition in appendix
    instruction: QPACKInstruction
    ? raw: RawInfo
}

Figure 29: QPACKInstructionCreated definition

Note: encoder/decoder semantics and stream_id's are implicit in either the instruction types or can be logged via other events (e.g., http.stream_type_set)¶

6.7. instruction_parsed

Importance: Base¶

This event is emitted when a QPACK instruction (both decoder and encoder) is read from the encoder/decoder stream.¶

Definition:¶

QPACKInstructionParsed = {
    ; see QPACKInstruction definition in appendix
    instruction: QPACKInstruction

    ? raw: RawInfo
}

Figure 30: QPACKInstructionParsed definition

Note: encoder/decoder semantics and stream_id's are implicit in either the instruction types or can be logged via other events (e.g., http.stream_type_set)¶

7. QPACK Data Field Definitions

The following data field definitions can be used in QPACK events.¶

7.1. QPACKInstruction

Note: the instructions do not have explicit encoder/decoder types, since there is no overlap between the instructions of both types in neither name nor function.¶

QPACKInstruction =  SetDynamicTableCapacityInstruction /
                    InsertWithNameReferenceInstruction /
                    InsertWithoutNameReferenceInstruction /
                    DuplicateInstruction /
                    SectionAcknowledgementInstruction /
                    StreamCancellationInstruction /
                    InsertCountIncrementInstruction

Figure 31: QPACKInstruction definition

7.1.1. SetDynamicTableCapacityInstruction

SetDynamicTableCapacityInstruction = {
    instruction_type: "set_dynamic_table_capacity"
    capacity: uint32
}

Figure 32: SetDynamicTableCapacityInstruction definition

7.1.2. InsertWithNameReferenceInstruction

InsertWithNameReferenceInstruction = {
    instruction_type: "insert_with_name_reference"
    table_type: QPACKTableType
    name_index: uint32
    huffman_encoded_value: bool
    ? value_length: uint32
    ? value: text
}

Figure 33: InsertWithNameReferenceInstruction definition

7.1.3. InsertWithoutNameReferenceInstruction

InsertWithoutNameReferenceInstruction = {
    instruction_type: "insert_without_name_reference"
    huffman_encoded_name: bool
    ? name_length: uint32
    ? name: text
    huffman_encoded_value: bool
    ? value_length: uint32
    ? value: text
}

Figure 34: InsertWithoutNameReferenceInstruction definition

7.1.4. DuplicateInstruction

DuplicateInstruction = {
    instruction_type: "duplicate"
    index: uint32
}

Figure 35: DuplicateInstruction definition

7.1.5. SectionAcknowledgementInstruction

SectionAcknowledgementInstruction = {
    instruction_type: "section_acknowledgement"
    stream_id: uint64
}

Figure 36: SectionAcknowledgementInstruction definition

7.1.6. StreamCancellationInstruction

StreamCancellationInstruction = {
    instruction_type: "stream_cancellation"
    stream_id: uint64
}

Figure 37: StreamCancellationInstruction definition

7.1.7. InsertCountIncrementInstruction

InsertCountIncrementInstruction = {
    instruction_type: "insert_count_increment"
    increment: uint32
}

Figure 38: InsertCountIncrementInstruction definition

7.2. QPACKHeaderBlockRepresentation

QPACKHeaderBlockRepresentation =  IndexedHeaderField /
                                  LiteralHeaderFieldWithName /
                                  LiteralHeaderFieldWithoutName

Figure 39: QPACKHeaderBlockRepresentation definition

7.2.1. IndexedHeaderField

Note: also used for "indexed header field with post-base index"¶

IndexedHeaderField = {
    header_field_type: "indexed_header"

    ; MUST be "dynamic" if is_post_base is true
    table_type: QPACKTableType
    index: uint32

    ; to represent the "indexed header field with post-base index"
    ; header field type
    is_post_base: bool .default false
}

Figure 40: IndexedHeaderField definition

7.2.2. LiteralHeaderFieldWithName

Note: also used for "Literal header field with post-base name reference"¶

LiteralHeaderFieldWithName = {
    header_field_type: "literal_with_name"

    ; the 3rd "N" bit
    preserve_literal: bool

    ; MUST be "dynamic" if is_post_base is true
    table_type: QPACKTableType
    name_index: uint32
    huffman_encoded_value: bool
    ? value_length: uint32
    ? value: text

    ; to represent the "indexed header field with post-base index"
    ; header field type
    is_post_base: bool .default false
}

Figure 41: LiteralHeaderFieldWithName definition

7.2.3. LiteralHeaderFieldWithoutName

LiteralHeaderFieldWithoutName = {
    header_field_type: "literal_without_name"

    ; the 3rd "N" bit
    preserve_literal: bool
    huffman_encoded_name: bool
    ? name_length: uint32
    ? name: text

    huffman_encoded_value: bool
    ? value_length: uint32
    ? value: text
}

Figure 42: LiteralHeaderFieldWithoutName definition

7.3. QPACKHeaderBlockPrefix

QPACKHeaderBlockPrefix = {
    required_insert_count: uint32
    sign_bit: bool
    delta_base: uint32
}

Figure 43: QPACKHeaderBlockPrefix definition

7.4. QPACKTableType

QPACKTableType = "static" / "dynamic"

Figure 44: QPACKTableType definition

Appendix A. Change Log

A.1. Since draft-ietf-quic-qlog-h3-events-03:

Ensured consistent use of RawInfo to indicate raw wire bytes (#243)¶
Changed HTTPStreamTypeSet:raw_stream_type to stream_type_value (#54)¶
Changed HTTPUnknownFrame:raw_frame_type to frame_type_value (#54)¶
Renamed max_header_list_size to max_field_section_size (#282)¶

A.2. Since draft-ietf-quic-qlog-h3-events-02:

Renamed HTTPStreamType data to request (#222)¶
Added HTTPStreamType value unknown (#227)¶
Added HTTPUnknownFrame (#224)¶
Replaced old and new fields with stream_type in HTTPStreamTypeSet (#240)¶
Changed HTTPFrame to a CDDL plug type (#257)¶
Moved data definitions out of the appendix into separate sections¶
Added overview Table of Contents¶

A.3. Since draft-ietf-quic-qlog-h3-events-01:

No changes - new draft to prevent expiration¶

A.4. Since draft-ietf-quic-qlog-h3-events-00:

Change the data definition language from TypeScript to CDDL (#143)¶

A.5. Since draft-marx-qlog-event-definitions-quic-h3-02:

These changes were done in preparation of the adoption of the drafts by the QUIC working group (#137)¶
Split QUIC and HTTP/3 events into two separate documents¶
Moved RawInfo, Importance, Generic events and Simulation events to the main schema document.¶

A.6. Since draft-marx-qlog-event-definitions-quic-h3-01:

Major changes:¶

Moved data_moved from http to transport. Also made the "from" and "to" fields flexible strings instead of an enum (#111,#65)¶
Moved packet_type fields to PacketHeader. Moved packet_size field out of PacketHeader to RawInfo:length (#40)¶
Made events that need to log packet_type and packet_number use a header field instead of logging these fields individually¶
Added support for logging retry, stateless reset and initial tokens (#94,#86,#117)¶
Moved separate general event categories into a single category "generic" (#47)¶
Added "transport:connection_closed" event (#43,#85,#78,#49)¶
Added version_information and alpn_information events (#85,#75,#28)¶
Added parameters_restored events to help clarify 0-RTT behaviour (#88)¶

Smaller changes:¶

Merged loss_timer events into one loss_timer_updated event¶
Field data types are now strongly defined (#10,#39,#36,#115)¶
Renamed qpack instruction_received and instruction_sent to instruction_created and instruction_parsed (#114)¶
Updated qpack:dynamic_table_updated.update_type. It now has the value "inserted" instead of "added" (#113)¶
Updated qpack:dynamic_table_updated. It now has an "owner" field to differentiate encoder vs decoder state (#112)¶
Removed push_allowed from http:parameters_set (#110)¶
Removed explicit trigger field indications from events, since this was moved to be a generic property of the "data" field (#80)¶
Updated transport:connection_id_updated to be more in line with other similar events. Also dropped importance from Core to Base (#45)¶
Added length property to PaddingFrame (#34)¶
Added packet_number field to transport:frames_processed (#74)¶
Added a way to generically log packet header flags (first 8 bits) to PacketHeader¶
Added additional guidance on which events to log in which situations (#53)¶
Added "simulation:scenario" event to help indicate simulation details¶
Added "packets_acked" event (#107)¶
Added "datagram_ids" to the datagram_X and packet_X events to allow tracking of coalesced QUIC packets (#91)¶
Extended connection_state_updated with more fine-grained states (#49)¶

A.7. Since draft-marx-qlog-event-definitions-quic-h3-00:

Event and category names are now all lowercase¶
Added many new events and their definitions¶
"type" fields have been made more specific (especially important for PacketType fields, which are now called packet_type instead of type)¶
Events are given an importance indicator (issue #22)¶
Event names are more consistent and use past tense (issue #21)¶
Triggers have been redefined as properties of the "data" field and updated for most events (issue #23)¶