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)
|
|
---|---|---|---|
Authors | Mohamed Boucadair , Hadriel Kaplan , Robert Gilman , Simo Veikkolainen | ||
Last updated | 2018-12-20 | ||
Stream | ISE | ||
Formats | plain text html pdf htmlized 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 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect 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 . . . . . . . . . . . . . . . . . . . . . . . 22Show full document text