draft-ietf-avt-rtp-gsm-hr-02.txt   draft-ietf-avt-rtp-gsm-hr-03.txt 
Network Working Group X. Duan Network Working Group X. Duan
Internet-Draft S. Wang Internet-Draft S. Wang
Intended status: Standards Track China Mobile Communications Intended status: Standards Track China Mobile Communications
Expires: April 3, 2010 Corporation Expires: July 25, 2010 Corporation
M. Westerlund M. Westerlund
K. Hellwig K. Hellwig
I. Johansson I. Johansson
Ericsson AB Ericsson AB
Sept 30, 2009 January 21, 2010
RTP Payload format for GSM-HR RTP Payload format for GSM-HR
draft-ietf-avt-rtp-gsm-hr-02 draft-ietf-avt-rtp-gsm-hr-03
Abstract
This document specifies the payload format for packetization of the
GSM Half-Rate speech codec data into the Real-time Transport Protocol
(RTP). The payload format supports transmission of multiple frames
per payload and packet loss robustness methods using redundancy.
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
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 3, 2010. This Internet-Draft will expire on July 25, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2010 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 in effect on the date of Provisions Relating to IETF Documents
publication of this document (http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info) in effect on the date of
Please review these documents carefully, as they describe your rights publication of this document. Please review these documents
and restrictions with respect to this document. carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Abstract include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
This document specifies the payload format for packetization of the described in the BSD License.
GSM Half-Rate speech codec data into the Real-time Transport Protocol
(RTP). The payload format supports transmission of multiple frames
per payload and packet loss robustness methods using redundancy.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. GSM Half Rate . . . . . . . . . . . . . . . . . . . . . . . . 3 3. GSM Half Rate . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Payload format Capabilities . . . . . . . . . . . . . . . . . 4 4. Payload format Capabilities . . . . . . . . . . . . . . . . . 4
4.1. Use of Forward Error Correction (FEC) . . . . . . . . . . 4 4.1. Use of Forward Error Correction (FEC) . . . . . . . . . . 4
5. Payload format . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Payload format . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. RTP Header Usage . . . . . . . . . . . . . . . . . . . . . 6 5.1. RTP Header Usage . . . . . . . . . . . . . . . . . . . . . 6
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parameters. So an implementation of this payload format in an parameters. So an implementation of this payload format in an
application using SDP is required to understand all the payload application using SDP is required to understand all the payload
parameters in their SDP-mapped form. This requirement ensures that parameters in their SDP-mapped form. This requirement ensures that
an implementation always can decide whether it is capable of an implementation always can decide whether it is capable of
communicating when the communicating entities support this version of communicating when the communicating entities support this version of
the specification. the specification.
5.3.1. Transmission of SID frames 5.3.1. Transmission of SID frames
When using this RTP payload format the sender SHOULD generate and When using this RTP payload format the sender SHOULD generate and
send SID frames every 160ms, i.e. every 8th frame. Other SID send SID frames every 160ms, i.e. every 8th frame, during silent
transmission intervals may occur due to gateways to other systems periods. Other SID transmission intervals may occur due to gateways
that uses other transmission intervals. to other systems that uses other transmission intervals.
5.3.2. Receiving Redundant Frames 5.3.2. Receiving Redundant Frames
The reception of redundant audio frames, i.e. more than one audio The reception of redundant audio frames, i.e. more than one audio
frame from the same source for the same time slot, MUST be supported frame from the same source for the same time slot, MUST be supported
by the implementation. by the implementation.
5.3.3. Decoding Validation 5.3.3. Decoding Validation
If the receiver finds a mismatch between the size of a received If the receiver finds a mismatch between the size of a received
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