Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal
RFC 8445

Document Type RFC - Proposed Standard (July 2018; No errata)
Obsoletes RFC 5245
Last updated 2018-07-19
Replaces draft-ietf-mmusic-rfc5245bis
Stream IETF
Formats plain text pdf html bibtex
Reviews
Stream WG state Submitted to IESG for Publication (wg milestone: Dec 2016 - Submit a revision of... )
Document shepherd Peter Thatcher
Shepherd write-up Show (last changed 2018-01-12)
IESG IESG state RFC 8445 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Ben Campbell
Send notices to "Peter Thatcher" <pthatcher@google.com>
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                        A. Keranen
Request for Comments: 8445                                   C. Holmberg
Obsoletes: 5245                                                 Ericsson
Category: Standards Track                                   J. Rosenberg
ISSN: 2070-1721                                              jdrosen.net
                                                               July 2018

             Interactive Connectivity Establishment (ICE):
       A Protocol for Network Address Translator (NAT) Traversal

Abstract

   This document describes a protocol for Network Address Translator
   (NAT) traversal for UDP-based communication.  This protocol is called
   Interactive Connectivity Establishment (ICE).  ICE makes use of the
   Session Traversal Utilities for NAT (STUN) protocol and its
   extension, Traversal Using Relay NAT (TURN).

   This document obsoletes RFC 5245.

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/rfc8445.

Keranen, et al.              Standards Track                    [Page 1]
RFC 8445                           ICE                         July 2018

Copyright Notice

   Copyright (c) 2018 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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Keranen, et al.              Standards Track                    [Page 2]
RFC 8445                           ICE                         July 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  Overview of ICE . . . . . . . . . . . . . . . . . . . . . . .   6
     2.1.  Gathering Candidates  . . . . . . . . . . . . . . . . . .   8
     2.2.  Connectivity Checks . . . . . . . . . . . . . . . . . . .  10
     2.3.  Nominating Candidate Pairs and Concluding ICE . . . . . .  12
     2.4.  ICE Restart . . . . . . . . . . . . . . . . . . . . . . .  13
     2.5.  Lite Implementations  . . . . . . . . . . . . . . . . . .  13
   3.  ICE Usage . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   4.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .  13
   5.  ICE Candidate Gathering and Exchange  . . . . . . . . . . . .  17
     5.1.  Full Implementation . . . . . . . . . . . . . . . . . . .  17
       5.1.1.  Gathering Candidates  . . . . . . . . . . . . . . . .  18
         5.1.1.1.  Host Candidates . . . . . . . . . . . . . . . . .  18
         5.1.1.2.  Server-Reflexive and Relayed Candidates . . . . .  20
         5.1.1.3.  Computing Foundations . . . . . . . . . . . . . .  21
         5.1.1.4.  Keeping Candidates Alive  . . . . . . . . . . . .  21
       5.1.2.  Prioritizing Candidates . . . . . . . . . . . . . . .  22
         5.1.2.1.  Recommended Formula . . . . . . . . . . . . . . .  22
         5.1.2.2.  Guidelines for Choosing Type and Local
                   Preferences . . . . . . . . . . . . . . . . . . .  23
       5.1.3.  Eliminating Redundant Candidates  . . . . . . . . . .  23
     5.2.  Lite Implementation Procedures  . . . . . . . . . . . . .  23
     5.3.  Exchanging Candidate Information  . . . . . . . . . . . .  24
     5.4.  ICE Mismatch  . . . . . . . . . . . . . . . . . . . . . .  26
Show full document text