The Session Description Protocol (SDP) Alternate Connectivity (ALTC) Attribute
RFC 6947
| Document | Type |
RFC - Informational
(May 2013; No errata)
Was draft-boucadair-mmusic-altc (individual)
|
|
|---|---|---|---|
| Last updated | 2018-12-20 | ||
| Stream | ISE | ||
| Formats | plain text pdf html bibtex | ||
| IETF conflict review | conflict-review-boucadair-mmusic-altc | ||
| Stream | ISE state | Published RFC | |
| Consensus Boilerplate | Unknown | ||
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 6947 (Informational) | |
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Independent Submission M. Boucadair
Request for Comments: 6947 France Telecom
Category: Informational H. Kaplan
ISSN: 2070-1721 Acme Packet
R. Gilman
Independent
S. Veikkolainen
Nokia
May 2013
The Session Description Protocol (SDP)
Alternate Connectivity (ALTC) Attribute
Abstract
This document proposes a mechanism that allows the same SDP offer to
carry multiple IP addresses of different address families (e.g., IPv4
and IPv6). The proposed attribute, the "altc" attribute, solves the
backward-compatibility problem that plagued Alternative Network
Address Types (ANAT) due to their syntax.
The proposed solution is applicable to scenarios where connectivity
checks are not required. If connectivity checks are required,
Interactive Connectivity Establishment (ICE), as specified in RFC
5245, provides such a solution.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see 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/rfc6947.
Boucadair, et al. Informational [Page 1]
RFC 6947 SDP Alternate Connectivity Attribute May 2013
Copyright Notice
Copyright (c) 2013 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
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to this document.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Overall Context . . . . . . . . . . . . . . . . . . . . . 3
1.2. Purpose . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4. Requirements Language . . . . . . . . . . . . . . . . . . 5
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Overview of the ALTC Mechanism . . . . . . . . . . . . . . . 6
3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Rationale for the Chosen Syntax . . . . . . . . . . . . . 7
4. Alternate Connectivity Attribute . . . . . . . . . . . . . . 8
4.1. ALTC Syntax . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. Usage and Interaction . . . . . . . . . . . . . . . . . . 9
4.2.1. Usage . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2.2. Usage of ALTC in an SDP Answer . . . . . . . . . . . 11
4.2.3. Interaction with ICE . . . . . . . . . . . . . . . . 11
4.2.4. Interaction with SDP-Cap-Neg . . . . . . . . . . . . 11
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. ALTC Use Cases . . . . . . . . . . . . . . . . . . . 15
A.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 15
A.2. Multicast Use Case . . . . . . . . . . . . . . . . . . . 16
A.3. Introducing IPv6 into SIP-Based Architectures . . . . . . 17
A.3.1. Avoiding Crossing CGN Devices . . . . . . . . . . . . 17
A.3.2. Basic Scenario for IPv6 SIP Service Delivery . . . . 17
A.3.3. Avoiding IPv4/IPv6 Interworking . . . . . . . . . . . 18
A.3.4. DBE Bypass Procedure . . . . . . . . . . . . . . . . 20
A.3.5. Direct Communications between IPv6-Enabled User
Agents . . . . . . . . . . . . . . . . . . . . . . . 22
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