Piggybacked DTLS Handshakes in SDP
draft-rescorla-dtls-in-sdp-01

Document Type Active Internet-Draft (individual)
Last updated 2016-10-31
Stream (None)
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
RTCWEB WG                                                    E. Rescorla
Internet-Draft                                                RTFM, Inc.
Intended status: Informational                          October 31, 2016
Expires: May 4, 2017

                   Piggybacked DTLS Handshakes in SDP
                     draft-rescorla-dtls-in-sdp-01

Abstract

   This document describes a mechanism for embedding DTLS handshake
   messages in SDP descriptions.  This technique allows implementations
   to shave a full round-trip off of DTLS-SRTP session establishment,
   while retaining compatibility with ordinary DTLS-SRTP endpoints.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 4, 2017.

Copyright Notice

   Copyright (c) 2016 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
   (http://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.

Rescorla                   Expires May 4, 2017                  [Page 1]
Internet-Draft                 DTLS in SDP                  October 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  DTLS 1.2  . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  DTLS 1.3  . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Attribute Definition  . . . . . . . . . . . . . . . . . . . .   7
   4.  Interactions  . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  ICE . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Forking . . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  RTCWEB Identity . . . . . . . . . . . . . . . . . . . . .   8
   5.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
     8.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Appendix A.  Speculative: Server False-Start  . . . . . . . . . .  11
   Appendix B.  Acknowledgements . . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   DTLS-SRTP [RFC5763][RFC5763] uses a DTLS [RFC6347] handshake to
   establish keys which are then used to key SRTP [RFC3711].  The DTLS
   negotiation is tied to the offer/answer [RFC3264] transaction via an
   "a=fingerprint" attribute [RFC4572] in the SDP [RFC4566].  The common
   message flow is shown below for DTLS 1.2.

   This figure and the rest of this document adopt the following
   assumptions about network behavior:

   o  ICE [RFC5245] is in use but that both endpoints implement
      endpoint-independent filtering [RFC5389] so that STUN checks
      succeed immediately.

   o  Signaling messages take the same time to be delivered as direct
      messages [this is generally false.]

   Links to detailed diagrams with a more accurate vertical scale can be
   found below each diagram.

Rescorla                   Expires May 4, 2017                  [Page 2]
Internet-Draft                 DTLS in SDP                  October 2016

       Alice                 Signaling Service                 Bob
       -----------------------------------------------------------
   ^   Offer + fingerprint  --------->
Show full document text