JavaScript Session Establishment Protocol (JSEP)
RFC 8829

Document Type RFC - Proposed Standard (January 2021; No errata)
Authors Justin Uberti  , Cullen Jennings  , Eric Rescorla 
Last updated 2021-01-20
Replaces draft-uberti-rtcweb-jsep
Stream Internet Engineering Task Force (IETF)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Stream WG state Submitted to IESG for Publication
Document shepherd Ted Hardie
Shepherd write-up Show (last changed 2017-07-06)
IESG IESG state RFC 8829 (Proposed Standard)
Action Holders
Consensus Boilerplate Yes
Telechat date
Responsible AD Adam Roach
Send notices to Ted Hardie <>
IANA IANA review state IANA OK - No Actions Needed
IANA action state No IANA Actions

Internet Engineering Task Force (IETF)                         J. Uberti
Request for Comments: 8829                                        Google
Category: Standards Track                                    C. Jennings
ISSN: 2070-1721                                                    Cisco
                                                        E. Rescorla, Ed.
                                                            January 2021

            JavaScript Session Establishment Protocol (JSEP)


   This document describes the mechanisms for allowing a JavaScript
   application to control the signaling plane of a multimedia session
   via the interface specified in the W3C RTCPeerConnection API and
   discusses how this relates to existing signaling protocols.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
     1.1.  General Design of JSEP
     1.2.  Other Approaches Considered
     1.3.  Contradiction regarding bundle-only "m=" sections
   2.  Terminology
   3.  Semantics and Syntax
     3.1.  Signaling Model
     3.2.  Session Descriptions and State Machine
     3.3.  Session Description Format
     3.4.  Session Description Control
       3.4.1.  RtpTransceivers
       3.4.2.  RtpSenders
       3.4.3.  RtpReceivers
     3.5.  ICE
       3.5.1.  ICE Gathering Overview
       3.5.2.  ICE Candidate Trickling  ICE Candidate Format
       3.5.3.  ICE Candidate Policy
       3.5.4.  ICE Candidate Pool
       3.5.5.  ICE Versions
     3.6.  Video Size Negotiation
       3.6.1.  Creating an imageattr Attribute
       3.6.2.  Interpreting imageattr Attributes
     3.7.  Simulcast
     3.8.  Interactions with Forking
       3.8.1.  Sequential Forking
       3.8.2.  Parallel Forking
   4.  Interface
     4.1.  PeerConnection
       4.1.1.  Constructor
       4.1.2.  addTrack
       4.1.3.  removeTrack
       4.1.4.  addTransceiver
       4.1.5.  onaddtrack Event
       4.1.6.  createDataChannel
       4.1.7.  ondatachannel Event
       4.1.8.  createOffer
       4.1.9.  createAnswer
       4.1.10. SessionDescriptionType  Use of Provisional Answers  Rollback
       4.1.11. setLocalDescription
       4.1.12. setRemoteDescription
       4.1.13. currentLocalDescription
       4.1.14. pendingLocalDescription
       4.1.15. currentRemoteDescription
       4.1.16. pendingRemoteDescription
       4.1.17. canTrickleIceCandidates
       4.1.18. setConfiguration
       4.1.19. addIceCandidate
       4.1.20. onicecandidate Event
     4.2.  RtpTransceiver
       4.2.1.  stop
       4.2.2.  stopped
       4.2.3.  setDirection
       4.2.4.  direction
       4.2.5.  currentDirection
       4.2.6.  setCodecPreferences
   5.  SDP Interaction Procedures
     5.1.  Requirements Overview
       5.1.1.  Usage Requirements
       5.1.2.  Profile Names and Interoperability
     5.2.  Constructing an Offer
       5.2.1.  Initial Offers
       5.2.2.  Subsequent Offers
       5.2.3.  Options Handling  IceRestart  VoiceActivityDetection
     5.3.  Generating an Answer
       5.3.1.  Initial Answers
       5.3.2.  Subsequent Answers
       5.3.3.  Options Handling  VoiceActivityDetection
     5.4.  Modifying an Offer or Answer
     5.5.  Processing a Local Description
     5.6.  Processing a Remote Description
     5.7.  Processing a Rollback
     5.8.  Parsing a Session Description
       5.8.1.  Session-Level Parsing
       5.8.2.  Media Section Parsing
       5.8.3.  Semantics Verification
     5.9.  Applying a Local Description
     5.10. Applying a Remote Description
     5.11. Applying an Answer
Show full document text