draft-ietf-mmusic-sdp-g723-g729-04.txt   draft-ietf-mmusic-sdp-g723-g729-05.txt 
MMUSIC Muthu A M. Perumal MMUSIC Muthu A M. Perumal
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Updates: 4856 (if approved) Parthasarathi. Ravindran Intended status: Standards Track Parthasarathi. Ravindran
Intended status: Standards Track Nokia Siemens Networks Expires: August 2, 2014 Nokia Solutions and Networks
Expires: January 16, 2014 July 15, 2013 January 29, 2014
Offer/Answer Considerations for G723 Annex A and G729 Annex B Offer/Answer Considerations for G723 Annex A and G729 Annex B
draft-ietf-mmusic-sdp-g723-g729-04 draft-ietf-mmusic-sdp-g723-g729-05
Abstract Abstract
RFC4856 describes the annexa parameter for G723 and the annexb This document provides the offer/answer considerations for the annexa
parameter for G729, G729D and G729E. However, the specification does parameter of G723 and the annexb parameter of G729, G729D and G729E
not describe the offerer and answerer behavior when the value of the when the value of the annexa or annexb parameter does not match in
annexa or annexb parameter does not match in the Session Description the Session Description protocol (SDP) offer and answer.
protocol(SDP) offer and answer. This document provides the offer/
answer considerations for these parameters and updates RFC4856.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF 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
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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 January 16, 2014. This Internet-Draft will expire on August 2, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 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
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Offer/Answer Considerations . . . . . . . . . . . . . . . . . . 4 3. Offer/Answer Considerations . . . . . . . . . . . . . . . . . . 3
3.1. Offer/Answer Considerations for G723 Annex A . . . . . . . 4 3.1. Offer/Answer Considerations for G723 Annex A . . . . . . . 4
3.2. Offer/Answer Considerations for G729 Annex B, G729D 3.2. Offer/Answer Considerations for G729 Annex B, G729D
Annex B and G729E Annex B . . . . . . . . . . . . . . . . . 4 Annex B and G729E Annex B . . . . . . . . . . . . . . . . . 4
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Offer with G729 annexb=yes and answer with G729 4.1. Offer with G729 annexb=yes and answer with G729
annexb=no . . . . . . . . . . . . . . . . . . . . . . . . . 5 annexb=no . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Offer with G729 annexb=yes and answer with G729 and no 4.2. Offer with G729 annexb=yes and answer with G729 and no
annexb parameter . . . . . . . . . . . . . . . . . . . . . 6 annexb parameter . . . . . . . . . . . . . . . . . . . . . 6
4.3. Offer with G729 and no annexb parameter and answer 4.3. Offer with G729 and no annexb parameter and answer
with G729 annexb=no . . . . . . . . . . . . . . . . . . . . 6 with G729 annexb=no . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . 7
8. Normative References . . . . . . . . . . . . . . . . . . . . . 8 8. Normative References . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
[RFC4856] describes the annexa parameter for G723 as follows: [RFC4856] describes the annexa parameter for G723 as follows:
annexa: indicates that Annex A, voice activity detection, is used annexa: indicates that Annex A, voice activity detection, is used
or preferred. Permissible values are "yes" and "no" (without the or preferred. Permissible values are "yes" and "no" (without the
quotes); "yes" is implied if this parameter is omitted. quotes); "yes" is implied if this parameter is omitted.
Also, [RFC4856] describes the annexb parameter for G729, G729D and Also, [RFC4856] describes the annexb parameter for G729, G729D and
G729E as follows: G729E as follows:
annexb: indicates that Annex B, voice activity detection, is used annexb: indicates that Annex B, voice activity detection, is used
or preferred. Permissible values are "yes" and "no" (without the or preferred. Permissible values are "yes" and "no" (without the
quotes); "yes" is implied if this parameter is omitted. quotes); "yes" is implied if this parameter is omitted.
However, it does not have any normative statement for the case where However, problem arises when the value of the annexa or annexb
the value of this parameter does not match in the SDP [RFC4566] offer parameter does not match in the SDP [RFC4566] offer and answer.
and answer. For example, if the offer has G729 with annexb=yes and
the answer has G729 with annexb=no, it can be interpreted in two For example, if the offer has G729 with annexb=yes and the answer has
different ways: G729 with annexb=no, it can be interpreted in two different ways:
o The offerer and answerer proceed as if G729 is negotiated with o The offerer and answerer proceed as if G729 is negotiated with
annexb=yes, or annexb=yes, or
o The offerer and answerer proceed as if G729 is negotiated with o The offerer and answerer proceed as if G729 is negotiated with
annexb=no. annexb=no.
Since [RFC4856] does not state it clearly, various implementations Since this is not clear in the existing specifications, various
have interpreted the offer/answer in their own ways, resulting in a implementations have interpreted the offer/answer in their own ways,
different codec being chosen to call failure, when the parameter resulting in a different codec being chosen to call failure, when the
value does not match in the offer and answer. parameter value does not match in the offer and answer.
[RFC3264] requires SDP extensions that define new fmtp parameters to [RFC3264] requires SDP extensions that define new fmtp parameters to
specify their proper interpretation in offer/answer. But, [RFC4856] specify their proper interpretation in offer/answer. This document
does not specify it for the Annex A flavor of G723 and the Annex B specifies the proper interpretation for the annexa and annexb
flavors of G729, G729D and G729E. parameters in offer/answer.
This document describes the offer/answer considerations for these
parameters and provides the necessary clarifications.
2. Terminology 2. Terminology
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 [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Offer/Answer Considerations 3. Offer/Answer Considerations
[RFC3551] states that [RFC3551] states that
skipping to change at page 7, line 38 skipping to change at page 7, line 38
5. Security Considerations 5. Security Considerations
There is no extra security consideration apart from what is described There is no extra security consideration apart from what is described
in [RFC4856]. in [RFC4856].
6. IANA Considerations 6. IANA Considerations
There is no IANA consideration for this draft. There is no IANA consideration for this draft.
7. Acknowledgement 7. Acknowledgment
Thanks to Flemming Andreasen (Cisco), Miguel A. Garcia (Ericsson), Thanks to Flemming Andreasen (Cisco), Miguel A. Garcia (Ericsson),
Ali C. Begen (Cisco), Paul Kyzivat (Huawei), Roni Even (Huawei), Ali C. Begen (Cisco), Paul Kyzivat (Huawei), Roni Even (Huawei),
Kevin Riley (Sonus), Ashish Sharma (Sonus), Kevin P. Fleming Kevin Riley (Sonus), Ashish Sharma (Sonus), Kevin P. Fleming
(Digium), Dale Worley (Avaya), Cullen Jennings (Cisco), Ari Keranen (Digium), Dale Worley (Avaya), Cullen Jennings (Cisco), Ari Keranen
(Ericsson), Harprit S. Chhatwal (InnoMedia) and Aurelien Sollaud (Ericsson), Harprit S. Chhatwal (InnoMedia), Aurelien Sollaud
(Orange) for their valuable inputs and comments. Martin Dolly (ATT) (Orange), SM, Stephen Casner and Keith Drage (Alcatel-Lucent) for
and Hadriel Kaplan (Acme Packet) provided useful suggestions at the their valuable inputs and comments. Martin Dolly (ATT) and Hadriel
mic at IETF-83. Kaplan (Acme Packet) provided useful suggestions at the mic at
IETF-83.
8. Normative References 8. Normative References
[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.
skipping to change at page 8, line 37 skipping to change at page 8, line 37
Muthu Arul Mozhi Perumal Muthu Arul Mozhi Perumal
Cisco Systems Cisco Systems
Cessna Business Park Cessna Business Park
Sarjapur-Marathahalli Outer Ring Road Sarjapur-Marathahalli Outer Ring Road
Bangalore, Karnataka 560103 Bangalore, Karnataka 560103
India India
Email: mperumal@cisco.com Email: mperumal@cisco.com
Parthasarathi Ravindran Parthasarathi Ravindran
Nokia Siemens Networks Nokia Solutions and Networks
Manyata Embassy Business park Manyata Embassy Business park
Bangalore, Karnataka Bangalore, Karnataka 560045
India India
Email: partha@parthasarathi.co.in Email: partha@parthasarathi.co.in
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