Session Description Protocol (SDP) Offer/Answer Considerations for Datagram Transport Layer Security (DTLS) and Transport Layer Security (TLS)
RFC 8842
Internet Engineering Task Force (IETF) C. Holmberg
Request for Comments: 8842 Ericsson
Updates: 5763, 7345 R. Shpount
Category: Standards Track TurboBridge
ISSN: 2070-1721 January 2021
Session Description Protocol (SDP) Offer/Answer Considerations for
Datagram Transport Layer Security (DTLS) and Transport Layer Security
(TLS)
Abstract
This document defines the Session Description Protocol (SDP) offer/
answer procedures for negotiating and establishing a Datagram
Transport Layer Security (DTLS) association. The document also
defines the criteria for when a new DTLS association must be
established. The document updates RFCs 5763 and 7345 by replacing
common SDP offer/answer procedures with a reference to this
specification.
This document defines a new SDP media-level attribute, "tls-id".
This document also defines how the "tls-id" attribute can be used for
negotiating and establishing a Transport Layer Security (TLS)
connection, in conjunction with the procedures in RFCs 4145 and 8122.
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/rfc8842.
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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction
2. Conventions
3. Establishing a New DTLS Association
3.1. General
3.2. Change of Local Transport Parameters
3.3. Change of ICE ufrag Value
4. SDP "tls-id" Attribute
5. SDP Offer/Answer Procedures
5.1. General
5.2. Generating the Initial SDP Offer
5.3. Generating the Answer
5.4. Offerer Processing of the SDP Answer
5.5. Modifying the Session
6. ICE Considerations
7. TLS Considerations
8. SIP Considerations
9. RFC Updates
9.1. General
9.2. Update to RFC 5763
9.2.1. Update to Section 1
9.2.2. Update to Section 5
9.2.3. Update to Section 6.6
9.2.4. Update to Section 6.7.1
9.3. Update to RFC 7345
9.3.1. Update to Section 4
9.3.2. Update to Section 5.2.1
9.3.3. Update to Section 9.1
10. Security Considerations
11. IANA Considerations
12. References
12.1. Normative References
12.2. Informative References
Acknowledgements
Authors' Addresses
1. Introduction
[RFC5763] defines Session Description Protocol (SDP) offer/answer
procedures for Secure Real-time Transport Protocol using Datagram
Transport Layer Security (DTLS-SRTP). [RFC7345] defines SDP offer/
answer procedures for UDP Transport Layer over Datagram Transport
Layer Security (UDPTL-DTLS). This specification defines general
offer/answer procedures for DTLS, based on the procedures in
[RFC5763]. Other specifications, defining specific DTLS usages, can
then reference this specification, in order to ensure that the DTLS
aspects are common among all usages. Having common procedures is
essential when multiple usages share the same DTLS association
[RFC8843]. This document updates [RFC5763] and [RFC7345] by
replacing common SDP offer/answer procedures with a reference to this
specification.
| NOTE: Since the publication of [RFC5763], [RFC4474] has been
| obsoleted by [RFC8224]. The updating of the references (and
| the associated procedures) within [RFC5763] is outside the
| scope of this document. However, implementers of [RFC5763]
| applications are encouraged to implement [RFC8224] instead of
| [RFC4474].
As defined in [RFC5763], a new DTLS association MUST be established
when transport parameters are changed. Transport parameter change is
not well defined when Interactive Connectivity Establishment (ICE)
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