Internet-Draft mocha-reactions July 2026
Jennings & Nandakumar Expires 7 January 2027 [Page]
Workgroup:
Media Over QUIC
Internet-Draft:
draft-jennings-moq-mocha-reactions-00
Published:
Intended Status:
Standards Track
Expires:
Authors:
C. Jennings
Cisco
S. Nandakumar
Cisco

MOCHA Reactions: Real-Time Reactions over MoQ Transport

Abstract

This document specifies reactions for MOCHA (MoQ Open Communication & Hosting Architecture). It supports message-targeted reactions (emoji on a specific chat message) and standalone reactions (engagement signals such as applause or raised hands).

About This Document

This note is to be removed before publishing as an RFC.

Status information for this document may be found at https://datatracker.ietf.org/doc/draft-jennings-moq-mocha-reactions/.

Discussion of this document takes place on the Media Over QUIC Working Group 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/.

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1. Introduction

This document specifies how MOCHA enables real-time reaction exchange using MOQT's publish/subscribe model. Two modes are supported:

Message-Targeted Reactions:

Emoji responses referencing a specific chat message MsgID.

Standalone Reactions:

Standalone engagement signals (applause, raised hands) directed at the channel as a whole.

Both modes use the same track structure.

2. Conventions and Definitions

See BCP 14 [RFC2119] [RFC8174].

This document uses terminology defined in [MOCHA-ARCH] and MOQT primitives defined in [MoQTransport]. Message identifiers (MsgID) are defined in [MOCHA-CHAT].

3. Reaction Track Naming

3.1. Reactions Namespace 

  ("mocha_v1", <Provider>, <OrgID>, "reactions", <TeamID>,
   <ChannelID>, <HClientID>)

HClientID and HDevID are derived per [MOCHA-IDENTITY], Section "Identifier Derivation".

3.2. Track Names

Each device publishes reactions on its own track:

  react_v1_<HDevID>

3.3. Object Semantics

Within each group, reactions are assigned sequentially increasing Object IDs starting at 0. Each reaction occupies one MOQT object.

4. Reaction Format

4.1. Encoding

Reactions are encoded as JSON [JSON] and compressed per the MOCHA_COMPRESSION track property defined in [MOCHA-CHAT].

4.2. Reaction Structure 

{
  "type": 1,
  "value": "thumbs-up",
  "ts": 1715788800000,
  "sender": {
    "userId": "<obtained via credential, see MOCHA-IDENTITY>",
    "devId": "<obtained via credential, see MOCHA-IDENTITY>"
  },
  "target": {
    "msgId": "a1b2c3...f0a1b2"
  },
  "ext": {}
}

4.3. Fields

type (REQUIRED):

Integer reaction type. See Section 4.4.

value (REQUIRED):

String identifying the specific reaction (e.g., "thumbs-up", "fire", "raise").

ts (REQUIRED):

Creation time in milliseconds since Unix epoch.

sender (REQUIRED):

Object with userId and devId fields.

target (OPTIONAL):

Object with msgId field (hex-encoded MsgID per [MOCHA-CHAT]). Present for message-targeted reactions; absent for standalone reactions. {#target-field}

ext (OPTIONAL):

Extension fields. Implementations MUST ignore unknown keys.

4.4. Reaction Types

Table 1
Value Name Description
1 emoji Emoji reaction (heart, fire, thumbs-up)
2 vote Poll or vote response
3 raise Raise/lower hand
4 applause Applause or cheer
5 custom Application-defined reaction

Extensible via IANA registry.

4.5. Reaction Value Encoding

Each reaction type defines integer encodings for its values:

Emoji (type 1):

Table 2
Integer Value
1 thumbs-up
2 thumbs-down
3 heart
4 fire
5 laugh
6 sad
7 wow
8 clap
9 thinking
10 eyes

TODO: The range of emoji values to be supported is not clear at this point and further discussion is needed.

Values 11-127 are reserved for future standard emoji. Values 128+ are available for application-defined emoji.

Raise (type 3):

Table 3
Integer Value
1 raise
2 lower

Vote (type 2) and Applause (type 4) value encodings are application-defined.

4.6. Reaction Removal

To retract a reaction, a device publishes an object with the same type, value, and target, plus "remove": true. The receiver removes the matching reaction from display.

5. Sending Reactions

To send a reaction, a device publishes a MOQT object to its track within the reactions namespace.

5.1. Rate Limiting

  • Message-targeted: At most 1 reaction of a given type per message per device (newer replaces older).

  • Standalone: At most 1 reaction per second per device.

Relays MAY enforce rate limits and drop excess objects.

6. Receiving Reactions

A participant discovers reaction tracks via SUBSCRIBE_NAMESPACE on the reactions namespace prefix, then subscribes to the announced tracks.

6.1. Processing Message-Targeted Reactions

  1. Look up the referenced MsgID in the local message store.

  2. Display the reaction on that message.

  3. Same sender + same type + same target: newer replaces older.

  4. If remove=true, remove the matching reaction.

6.2. Processing Standalone Reactions

  1. Display as a transient signal (e.g., floating emoji, applause indicator).

  2. For raise-hand: maintain a queue until "lower" is received.

9. Normative References

[JSON]
Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, , <https://www.rfc-editor.org/rfc/rfc8259>.
[MOCHA]
"*** BROKEN REFERENCE ***".
[MOCHA-ARCH]
"*** BROKEN REFERENCE ***".
[MOCHA-CHAT]
"*** BROKEN REFERENCE ***".
[MOCHA-IDENTITY]
"*** BROKEN REFERENCE ***".
[MoQTransport]
Nandakumar, S., Vasiliev, V., Swett, I., and A. Frindell, "Media over QUIC Transport", Work in Progress, Internet-Draft, draft-ietf-moq-transport-18, , <https://datatracker.ietf.org/doc/html/draft-ietf-moq-transport-18>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.

Authors' Addresses

Cullen Jennings
Cisco
Suhas Nandakumar
Cisco