draft-ietf-mmusic-sdp-miscellaneous-caps-06.txt   draft-ietf-mmusic-sdp-miscellaneous-caps-07.txt 
MMUSIC WG M. Garcia-Martin MMUSIC WG M. Garcia-Martin
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track S. Veikkolainen Intended status: Standards Track S. Veikkolainen
Expires: December 07, 2013 Nokia Expires: January 11, 2014 Nokia
R. Gilman R. Gilman
June 05, 2013 July 10, 2013
Miscellaneous Capabilities Negotiation in the Session Description Miscellaneous Capabilities Negotiation in the Session Description
Protocol (SDP) Protocol (SDP)
draft-ietf-mmusic-sdp-miscellaneous-caps-06 draft-ietf-mmusic-sdp-miscellaneous-caps-07
Abstract Abstract
SDP has been extended with a capability negotiation mechanism SDP has been extended with a capability negotiation mechanism
framework that allows the endpoints to negotiate transport protocols framework that allows the endpoints to negotiate transport protocols
and attributes. This framework has been extended with a media and attributes. This framework has been extended with a media
capabilities negotiation mechanism that allows endpoints to negotiate capabilities negotiation mechanism that allows endpoints to negotiate
additional media-related capabilities. This negotiation is embedded additional media-related capabilities. This negotiation is embedded
into the widely-used SDP offer/answer procedures. into the widely-used SDP offer/answer procedures.
This memo extends the SDP capability negotiation framework to allow This memo extends the SDP capability negotiation framework to allow
endpoints to negotiate three additional SDP capabilities. In endpoints to negotiate three additional SDP capabilities. In
particular, this memo provides a mechanism to negotiate bandwidth particular, this memo provides a mechanism to negotiate bandwidth
('b=' line), connection data ('c=' line), and titles ('i=' line for ('b=' line), connection data ('c=' line), and session or media titles
each session or media). ('i=' line for each session or media).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 07, 2013. This Internet-Draft will expire on January 11, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
skipping to change at page 2, line 24 skipping to change at page 2, line 24
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. Protocol Description . . . . . . . . . . . . . . . . . . . . 3 3. Protocol Description . . . . . . . . . . . . . . . . . . . . 3
3.1. Extensions to SDP . . . . . . . . . . . . . . . . . . . . 3 3.1. Extensions to SDP . . . . . . . . . . . . . . . . . . . . 3
3.1.1. Bandwidth Capability . . . . . . . . . . . . . . . . 5 3.1.1. Bandwidth Capability . . . . . . . . . . . . . . . . 5
3.1.2. Connection Data Capability . . . . . . . . . . . . . 7 3.1.2. Connection Data Capability . . . . . . . . . . . . . 8
3.1.3. Title Capability . . . . . . . . . . . . . . . . . . 12 3.1.3. Title Capability . . . . . . . . . . . . . . . . . . 12
3.2. Session Level versus Media Level . . . . . . . . . . . . 15 3.2. Session Level versus Media Level . . . . . . . . . . . . 16
3.3. Offer/Answer model extensions . . . . . . . . . . . . . . 15 3.3. Offer/Answer model extensions . . . . . . . . . . . . . . 16
3.3.1. Generating the Initial Offer . . . . . . . . . . . . 15 3.3.1. Generating the Initial Offer . . . . . . . . . . . . 16
3.3.2. Generating the Answer . . . . . . . . . . . . . . . . 16 3.3.2. Generating the Answer . . . . . . . . . . . . . . . . 17
3.3.3. Offerer Processing of the Answer . . . . . . . . . . 16 3.3.3. Offerer Processing of the Answer . . . . . . . . . . 17
3.3.4. Modifying the Session . . . . . . . . . . . . . . . . 16 3.3.4. Modifying the Session . . . . . . . . . . . . . . . . 17
4. Field Replacement Rules . . . . . . . . . . . . . . . . . . . 17 4. Field Replacement Rules . . . . . . . . . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 5. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . 18 6.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . 19
6.2. New Option Tags . . . . . . . . . . . . . . . . . . . . . 19 6.2. New Option Tags . . . . . . . . . . . . . . . . . . . . . 19
6.3. New SDP Capability Negotiation Configuration Parameters 19 6.3. New SDP Capability Negotiation Configuration Parameters 20
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1. Normative References . . . . . . . . . . . . . . . . . . 19 8.1. Normative References . . . . . . . . . . . . . . . . . . 20
8.2. Informative References . . . . . . . . . . . . . . . . . 20 8.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction 1. Introduction
The Session Description Protocol (SDP) [RFC4566] is intended for The Session Description Protocol (SDP) [RFC4566] is intended for
describing multimedia sessions for the purposes of session describing multimedia sessions for the purposes of session
announcement, session invitation, and other forms of multimedia announcement, session invitation, and other forms of multimedia
session initiation. SDP has been extended with a SDP Capability session initiation. SDP has been extended with a SDP Capability
Negotiation Mechanism Framework [RFC5939] which allows the endpoints Negotiation Mechanism Framework [RFC5939] which allows the endpoints
to negotiate capabilities, such as support for Real-time Transport to negotiate capabilities, such as support for Real-time Transport
Protocol (RTP) [RFC3550] and Secure Real-time Transport Protocol Protocol (RTP) [RFC3550] and Secure Real-time Transport Protocol
skipping to change at page 3, line 25 skipping to change at page 3, line 25
Since the three added capabilities are independent, it is not Since the three added capabilities are independent, it is not
expected that implementations will necessarily support all of them at expected that implementations will necessarily support all of them at
the same time. Instead, it is expected that applications will choose the same time. Instead, it is expected that applications will choose
their needed capability for their specific purpose. Due to this, we their needed capability for their specific purpose. Due to this, we
are writing the normative part pertaining to each capability in a are writing the normative part pertaining to each capability in a
self-contained section: Section 3.1.1 describes the bandwidth self-contained section: Section 3.1.1 describes the bandwidth
capability extension, Section 3.1.2 describes the connection data capability extension, Section 3.1.2 describes the connection data
capability extension, and Section 3.1.3 describes the title capability extension, and Section 3.1.3 describes the title
capability extension. Separate SDP capability negotiation option capability extension. Separate SDP capability negotiation option
tags are defined for each capability. tags are defined for each capability, allowing endpoints to indicate
and/or require support for these extensions according to procedures
defined in SDP Capability Negotiation [RFC5939].
2. Conventions Used in This Document 2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119 document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119] and indicate requirement levels for compliant [RFC2119] and indicate requirement levels for compliant
implementations. implementations.
3. Protocol Description 3. Protocol Description
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indicates the purpose of the session or media stream it is supposed indicates the purpose of the session or media stream it is supposed
to characterize. to characterize.
As an example, one might use: As an example, one might use:
a=icap:1 Document Camera a=icap:1 Document Camera
to define a title capability number 1 to identify a particular source to define a title capability number 1 to identify a particular source
of a media stream. of a media stream.
Or in another example, one might offer two title capabilities with
different character encodings (using the charset attribute defined in
SDP: Session Description Protocol [RFC4566] and the generic attribute
capability attribute ("a=acap:") defined in SDP Capability
Negotiation [RFC5939].
a=icap:1 [Text encoded in ISO-8859-1]
a=acap:1 charset:ISO-8859-1
a=icap:2 [Text encoded in UTF-8]
a=acap:2 charset:UTF-8
NOTE: Due to limitations of the ASCII encoding of RFCs, the actual
text with non-printable characters cannot be represented in the text
version, but might be represented in other versions of this RFC.
The title capability attribute satisfies the general attribute The title capability attribute satisfies the general attribute
production rules in SDP [RFC4566] according to the following production rules in SDP [RFC4566] according to the following
Augmented Backus-Naur Form (ABNF) [RFC5234] syntax: Augmented Backus-Naur Form (ABNF) [RFC5234] syntax:
att-field =/ "icap" att-field =/ "icap"
att-value =/ title-cap-num 1*WSP text att-value =/ title-cap-num 1*WSP text
; text defined in RFC 4566 ; text defined in RFC 4566
title-cap-num = 1*10(DIGIT) ; DIGIT defined in RFC 5234 title-cap-num = 1*10(DIGIT) ; DIGIT defined in RFC 5234
Figure 11: Syntax of the icap attribute Figure 11: Syntax of the icap attribute
skipping to change at page 20, line 22 skipping to change at page 21, line 5
Description Protocol (SDP) Media Capabilities Description Protocol (SDP) Media Capabilities
Negotiation", RFC 6871, February 2013. Negotiation", RFC 6871, February 2013.
8.2. Informative References 8.2. Informative References
[I-D.ietf-mmusic-sdp-cs] [I-D.ietf-mmusic-sdp-cs]
Garcia, M. and S. Veikkolainen, "Session Description Garcia, M. and S. Veikkolainen, "Session Description
Protocol (SDP) Extension For Setting Audio and Video Media Protocol (SDP) Extension For Setting Audio and Video Media
Streams Over Circuit-Switched Bearers In The Public Streams Over Circuit-Switched Bearers In The Public
Switched Telephone Network (PSTN)", draft-ietf-mmusic-sdp- Switched Telephone Network (PSTN)", draft-ietf-mmusic-sdp-
cs-19 (work in progress), June 2013. cs-21 (work in progress), June 2013.
[RFC3108] Kumar, R. and M. Mostafa, "Conventions for the use of the [RFC3108] Kumar, R. and M. Mostafa, "Conventions for the use of the
Session Description Protocol (SDP) for ATM Bearer Session Description Protocol (SDP) for ATM Bearer
Connections", RFC 3108, May 2001. Connections", RFC 3108, May 2001.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
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