draft-ietf-mmusic-sdp-miscellaneous-caps-03.txt   draft-ietf-mmusic-sdp-miscellaneous-caps-04.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: June 15, 2013 Nokia Expires: September 14, 2013 Nokia
R. Gilman R. Gilman
December 12, 2012 March 13, 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-03 draft-ietf-mmusic-sdp-miscellaneous-caps-04
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.
skipping to change at page 1, line 44 skipping to change at page 1, line 44
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 June 15, 2013. This Internet-Draft will expire on September 14, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 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
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 2, line 25 skipping to change at page 2, line 25
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . . . . . 4 3.1. Extensions to SDP . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Bandwidth Capability . . . . . . . . . . . . . . . . . 6 3.1.1. Bandwidth Capability . . . . . . . . . . . . . . . . . 6
3.1.2. Connection Data Capability . . . . . . . . . . . . . . 8 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 . . . . . . . . . . . . . 15
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 . . . . . . . . . . . . . . . . 16
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 . . . . . . . . . . . . . . . . . . . 16 4. Field Replacement Rules . . . . . . . . . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 5. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . . 17 6.1. New SDP Attributes . . . . . . . . . . . . . . . . . . . . 18
6.2. New Option Tags . . . . . . . . . . . . . . . . . . . . . 18 6.2. New Option Tags . . . . . . . . . . . . . . . . . . . . . 19
6.3. New SDP Capability Negotiation Configuration Parameters . 18 6.3. New SDP Capability Negotiation Configuration Parameters . 19
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.1. Normative References . . . . . . . . . . . . . . . . . . . 19 8.1. Normative References . . . . . . . . . . . . . . . . . . . 19
8.2. Informative References . . . . . . . . . . . . . . . . . . 19 8.2. Informative References . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
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 capability session initiation. SDP has been extended with a 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
skipping to change at page 10, line 26 skipping to change at page 10, line 26
s=- s=-
t=0 0 t=0 0
m=audio 9 PSTN - m=audio 9 PSTN -
c=PSTN E164 +15555556666 c=PSTN E164 +15555556666
a=setup:actpass a=setup:actpass
a=connection:new a=connection:new
a=cs-correlation:callerid:+15555556666 a=cs-correlation:callerid:+15555556666
Figure 8: Equivalent SDP offer with the circuit-switched flow Figure 8: Equivalent SDP offer with the circuit-switched flow
This document does not define any mechanism for negotiating or
describing different port numbers and hence the port number from the
"m=" line MUST be used by default. Exceptions to this default can be
provided by extension mechanisms or network type specific rules.
This draft defines an exception when the network type is "PSTN", in
which case the port number is replaced with 9 (the "discard" port) as
described in Session Decription Protocol (SDP) Extension For Setting
Up Audio and Video Media Streams over Circuit-Switched Bearers in the
Public Switched Telephone Network (PSTN) [I-D.ietf-mmusic-sdp-cs]
3.1.2.1. Configuration Parameters 3.1.2.1. Configuration Parameters
The SDP Capability Negotiation Framework [RFC5939] provides for the The SDP Capability Negotiation Framework [RFC5939] provides for the
existence of the 'pcfg' and 'acfg' attributes, which can convey one existence of the 'pcfg' and 'acfg' attributes, which can convey one
or more configurations to be negotiated. The concept is extended by or more configurations to be negotiated. The concept is extended by
the Media Capabilities Negotiation the Media Capabilities Negotiation
[I-D.ietf-mmusic-sdp-media-capabilities] with an 'lcfg' attribute [I-D.ietf-mmusic-sdp-media-capabilities] with an 'lcfg' attribute
that conveys latent configurations. that conveys latent configurations.
In this document we define a <connection-config> parameter to be used In this document we define a <connection-config> parameter to be used
skipping to change at page 15, line 29 skipping to change at page 15, line 44
3.2. Session Level versus Media Level 3.2. Session Level versus Media Level
The 'bcap', 'ccap' and 'icap' attributes can appear at the SDP The 'bcap', 'ccap' and 'icap' attributes can appear at the SDP
session and/or media level. Endpoints MUST interpret capabilities session and/or media level. Endpoints MUST interpret capabilities
declared at session level as part of the session level in the declared at session level as part of the session level in the
resulting SDP for that particular configuration. Endpoints MUST resulting SDP for that particular configuration. Endpoints MUST
interpret capabilities declared at media description as part of the interpret capabilities declared at media description as part of the
media level in the resulting SDP for that particular configuration. media level in the resulting SDP for that particular configuration.
If a 'bcap' capability for the same bwtype is declared at both The presence of the 'bcap' capability for the same <bwtype> at both
session and media level, the media level attribute overrides the the session and media level is subject to the same constraints and
value of the session level attribute. restrictions specified in RFC 4566 [RFC4566] for the bandwidth
attribute "b=".
To avoid confusion, the <type-attr-num> for each 'a=bcap', 'a=ccap', To avoid confusion, the <type-attr-num> for each 'a=bcap', 'a=ccap',
and 'a=icap' line MUST be unique across all capability attributes of and 'a=icap' line MUST be unique across all capability attributes of
the same type within the entire session description. the same type within the entire session description.
3.3. Offer/Answer model extensions 3.3. Offer/Answer model extensions
In this section, we define extensions to the offer/answer model In this section, we define extensions to the offer/answer model
defined in SDP Offer/Answer Model [RFC3264] and extended in the SDP defined in SDP Offer/Answer Model [RFC3264] and extended in the SDP
Capability Negotiation [RFC5939] to allow for bandwidth, connection, Capability Negotiation [RFC5939] to allow for bandwidth, connection,
skipping to change at page 16, line 11 skipping to change at page 16, line 27
appropriate values for the bandwidth, connection data, and/or title appropriate values for the bandwidth, connection data, and/or title
capability attributes according to the rules defined in [RFC4566] for capability attributes according to the rules defined in [RFC4566] for
'b=', 'c=' and 'i=' lines. The endpoint then MUST include the 'b=', 'c=' and 'i=' lines. The endpoint then MUST include the
respective capability attributes and associated values in the SDP respective capability attributes and associated values in the SDP
offer. The preferred configurations for each media stream are offer. The preferred configurations for each media stream are
identified following the media line in a 'pcfg' attribute. Bandwidth identified following the media line in a 'pcfg' attribute. Bandwidth
and title capabilities may also be referenced in latent and title capabilities may also be referenced in latent
configurations in an 'lcfg' attribute, defined in SDP Media configurations in an 'lcfg' attribute, defined in SDP Media
Capabilities [I-D.ietf-mmusic-sdp-media-capabilities]. Capabilities [I-D.ietf-mmusic-sdp-media-capabilities].
Implementations are advised to pay attention to the port number that
is used in the "m=" line. By default, a potential configuration that
includes a connection data capability will use the port number from
the "m=" line, unless the network type is "PSTN", in which case the
default port number used will be 9.
The offer SHOULD include the level of capability negotiation The offer SHOULD include the level of capability negotiation
extensions needed to support this functionality in a 'creq' extensions needed to support this functionality in a 'creq'
attribute. attribute.
3.3.2. Generating the Answer 3.3.2. Generating the Answer
When the answering party receives the offer, and if it supports the When the answering party receives the offer, and if it supports the
required capability negotiation extensions, it SHOULD select the most required capability negotiation extensions, it SHOULD select the most
preferred configuration it can support for each media stream, and preferred configuration it can support for each media stream, and
build the answer accordingly, as defined in Section 3.6.2 of the SDP build the answer accordingly, as defined in Section 3.6.2 of the SDP
Capability Negotiation [RFC5939]. Capability Negotiation [RFC5939].
If the connection data capability is used in a selected potential
configuration chosen by the answerer, that offer configuration MUST
by default use the port number from the actual offer configuration
(i.e. the "m=" line), unless the network type is "PSTN", in which
case the default port MUST be assumed to be 9. Extensions may be
defined to negotiate the port number explicitly instead.
3.3.3. Offerer Processing of the Answer 3.3.3. Offerer Processing of the Answer
When the offerer receives the answer, it MUST process the media lines When the offerer receives the answer, it MUST process the media lines
according to normal SDP processing rules to identify the media according to normal SDP processing rules to identify the media
stream(s) accepted by the answer, if any, as defined in Section 3.6.3 stream(s) accepted by the answer, if any, as defined in Section 3.6.3
of the SDP Capability Negotiation [RFC5939]. The 'acfg' attribute, of the SDP Capability Negotiation [RFC5939]. The 'acfg' attribute,
if present, MUST be used to verify the proposed configuration used to if present, MUST be used to verify the proposed configuration used to
form the answer, and to infer the lack of acceptability of higher- form the answer, and to infer the lack of acceptability of higher-
preference configurations that were not chosen. preference configurations that were not chosen.
skipping to change at page 19, line 12 skipping to change at page 19, line 35
it. Thanks to Flemming Andreasen, Andrew Allen, and Jonathan Lennox it. Thanks to Flemming Andreasen, Andrew Allen, and Jonathan Lennox
for a detailed review and many improvement suggestions. for a detailed review and many improvement suggestions.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-mmusic-sdp-media-capabilities] [I-D.ietf-mmusic-sdp-media-capabilities]
Gilman, R., Even, R., and F. Andreasen, "Session Gilman, R., Even, R., and F. Andreasen, "Session
Description Protocol (SDP) Media Capabilities Description Protocol (SDP) Media Capabilities
Negotiation", draft-ietf-mmusic-sdp-media-capabilities-15 Negotiation", draft-ietf-mmusic-sdp-media-capabilities-17
(work in progress), October 2012. (work in progress), January 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
June 2002. June 2002.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
skipping to change at page 19, line 38 skipping to change at page 20, line 15
[RFC5939] Andreasen, F., "Session Description Protocol (SDP) [RFC5939] Andreasen, F., "Session Description Protocol (SDP)
Capability Negotiation", RFC 5939, September 2010. Capability Negotiation", RFC 5939, September 2010.
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 Up Audio and Video Protocol (SDP) Extension For Setting Up Audio and Video
Media Streams Over Circuit-Switched Bearers In The Public Media Streams Over Circuit-Switched Bearers In The Public
Switched Telephone Network (PSTN)", Switched Telephone Network (PSTN)",
draft-ietf-mmusic-sdp-cs-14 (work in progress), draft-ietf-mmusic-sdp-cs-17 (work in progress),
November 2012. January 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.
skipping to change at page 20, line 23 skipping to change at page 21, line 4
Authors' Addresses Authors' Addresses
Miguel A. Garcia-Martin Miguel A. Garcia-Martin
Ericsson Ericsson
Calle Via de los Poblados 13 Calle Via de los Poblados 13
Madrid, 28033 Madrid, 28033
Spain Spain
Phone: +34 91 339 1000 Phone: +34 91 339 1000
Email: miguel.a.garcia@ericsson.com Email: miguel.a.garcia@ericsson.com
Simo Veikkolainen Simo Veikkolainen
Nokia Nokia
P.O. Box 407 P.O. Box 226
NOKIA GROUP, FI 00045 NOKIA GROUP, FI 00045
Finland Finland
Phone: +358 50 486 4463 Phone: +358 50 486 4463
Email: simo.veikkolainen@nokia.com Email: simo.veikkolainen@nokia.com
Robert R. Gilman Robert R. Gilman
3243 W. 11th Ave. Dr. 3243 W. 11th Ave. Dr.
Broomfield, Colorado 80020 Broomfield, Colorado 80020
U.S.A. U.S.A.
 End of changes. 17 change blocks. 
25 lines changed or deleted 48 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/