RFC 8829 - JavaScript Session Establishment Protocol (JSEP)

Published: January 2021

Authors:

• J. Uberti (Google)
• C. Jennings (Cisco)
• E. Rescorla, Ed. (Mozilla)

Abstract

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 https://www.rfc-editor.org/info/rfc8829.

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 (https://trustee.ietf.org/license-info) 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.

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
      • 3.5.2.1 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
      • 4.1.10.1 Use of Provisional Answers
      • 4.1.10.2 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
      • 5.2.3.1 IceRestart
      • 5.2.3.2 VoiceActivityDetection
  • 5.3 Generating an Answer
    • 5.3.1 Initial Answers
    • 5.3.2 Subsequent Answers
    • 5.3.3 Options Handling
      • 5.3.3.1 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
• 6. Processing RTP/RTCP
• 7. Examples
  • 7.1 Simple Example
  • 7.2 Detailed Example
  • 7.3 Early Transport Warmup Example
• 8. Security Considerations
• 9. IANA Considerations
• 10. References
  • 10.1 Normative References
  • 10.2 Informative References
• Appendix A. SDP ABNF Syntax
• Acknowledgements
• Authors' Addresses