Datagram Transport Layer Security (DTLS) for Stream Control Transmission Protocol (SCTP)
RFC 6083

Internet Engineering Task Force (IETF)                         M. Tuexen
Request for Comments: 6083                                 R. Seggelmann
Category: Standards Track             Muenster Univ. of Applied Sciences
ISSN: 2070-1721                                              E. Rescorla
                                                              RTFM, Inc.
                                                            January 2011

                Datagram Transport Layer Security (DTLS)
            for Stream Control Transmission Protocol (SCTP)

Abstract

   This document describes the usage of the Datagram Transport Layer
   Security (DTLS) protocol over the Stream Control Transmission
   Protocol (SCTP).

   DTLS over SCTP provides communications privacy for applications that
   use SCTP as their transport protocol and allows client/server
   applications to communicate in a way that is designed to prevent
   eavesdropping and detect tampering or message forgery.

   Applications using DTLS over SCTP can use almost all transport
   features provided by SCTP and its extensions.

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 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6083.

Tuexen, et al.               Standards Track                    [Page 1]
RFC 6083                      DTLS for SCTP                 January 2011

Copyright Notice

   Copyright (c) 2011 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
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   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  . . . . . . . . . . . . . . . . . . . . . . . . . 2
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   3.  DTLS Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   4.  SCTP Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.  Introduction

1.1.  Overview

   This document describes the usage of the Datagram Transport Layer
   Security (DTLS) protocol, as defined in [RFC4347], over the Stream
   Control Transmission Protocol (SCTP), as defined in [RFC4960].

   DTLS over SCTP provides communications privacy for applications that
   use SCTP as their transport protocol and allows client/server
   applications to communicate in a way that is designed to prevent
   eavesdropping and detect tampering or message forgery.

   Applications using DTLS over SCTP can use almost all transport
   features provided by SCTP and its extensions.

   TLS, from which DTLS was derived, is designed to run on top of a
   byte-stream-oriented transport protocol providing a reliable, in-
   sequence delivery.  Thus, TLS is currently mainly being used on top
   of the Transmission Control Protocol (TCP), as defined in [RFC0793].

Tuexen, et al.               Standards Track                    [Page 2]
RFC 6083                      DTLS for SCTP                 January 2011

   TLS over SCTP as described in [RFC3436] has some serious limitations:

   o  It does not support the unordered delivery of SCTP user messages.

   o  It does not support partial reliability as defined in [RFC3758].

   o  It only supports the usage of the same number of streams in both
      directions.

   o  It uses a TLS connection for every bidirectional stream, which
      requires a substantial amount of resources and message exchanges
      if a large number of streams is used.

   DTLS over SCTP as described in this document overcomes these
   limitations of TLS over SCTP.  In particular, DTLS/SCTP supports: