Internet Engineering Task Force A. Clark Internet-Draft Telchemy Incorporated Expires: 29th December 2007 A. Pendleton Nortel July 2007 RTCP XR - Audio Metrics Report Block draft-ietf-avt-rtcpxr-audio-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on 29th December 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines extensions to the RTCP XR extended report packet type blocks to support the performance monitoring of audio streams transmitted using RTP. This draft is one of a set of four that replace the -00 version of the ietf-avt-rtcpxr-video-00.txt draft. Clark [Page 1] draft-ietf-avt-rtcpxr-audio-00.txt July 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Audio Metrics Report Block . . . . . . . . . . . . . . . . . X 4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . X 5. Security Considerations . . . . . . . . . . . . . . . . . . 13 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . X 8. Informative References . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . Intellectual Property and Copyright Statements . . . . . . . 1. Introduction This draft defines a block type to augment those defined in RFC3611 for use in Quality of Service reporting for audio over IP. The new block type defined in this draft is the IP Audio Metrics Report Block. This is intended to support both the identification of problems affecting performance and the collection of data that may be useful in optimizing system configuration. Audio performance may be measured using zero (no) reference, partial (reduced) reference or full reference. The primary application of this draft is to support the reporting of real-time, in-service performance obtained using a zero or partial reference model however this approach could also be used to support the remote reporting of metrics from a full reference test. 2. Definitions 3 Audio Metrics Report Block 3.1 Block Description 0 1 2 3 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BT=N | Reserved | block length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSRC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0| Program ID | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Report Timestamp | Clark [Page 2] draft-ietf-avt-rtcpxr-audio-00.txt July 2007 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Measurement Interval (ms) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MOS-A - Audio Quality (M/L) | MOS-A Audio Quality (R) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mean Audio bit rate (bits/sec) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Round Trip Delay | A-V Delay (Video I/F) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Playout Interrupt Count | Mean Playout Interrupt Size | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Audio Playout buffer size | Mean buffer level | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 3.2 Definition of Metrics 3.2.1 Header The header comprises: (i) Block Type for this report block (ii) Reserved (set to 0xFF) (iii) Block length in words (set to 0x0009) (iv) SSRC of the received RTP stream that this report refers to (v) Program ID (PID) for the audio stream (if MPEG Transport encapsulation is used) (vi) Reserved (set to 0xFFFF) 3.2.2 Report Timestamp The time at which this report was generated (format?) 3.2.3 Measurement Interval The interval of time over which these metrics were measured, expressed in milliseconds. 3.2.4 MOS-A (M/L) and MOS-A (R) An estimate of the quality of the received audio stream expressed as a Mean Opinion Score. (i) MOS-A (M/L). The quality score for a monophonic stream or the Left channel for a stereophonic stream (ii) MOS-A (R). The quality score for the Right channel of a stereophonic stream 3.2.5 Mean Audio Bit Rate The average bit rate of the audio stream expressed in bits per second. 3.2.6 Round Trip Delay The Round Trip Delay between the originating and terminating ends of this RTP stream, expressed in millseconds. In unicast or multicast applications this parameter may be set to "undefined" (0xFFFF). Clark [Page 3] draft-ietf-avt-rtcpxr-audio-00.txt July 2007 3.2.7 A-V Delay The relative delay between decoded audio and video streams expressed in milliseconds. 3.2.8 Playout Interrupt Count The number of interruptions that occurred during playout, due to either packet loss or buffer underrun. 3.2.9 Mean Playout Interrupt Size The mean duration of interruptions in playout expressed in milliseconds. 3.2.10 Audio Playout Buffer Size The available playout buffer size, expressed in milliseconds. 3.2.11 Mean Buffer Level The mean playout buffer size, expressed in milliseconds. 4. Summary This draft defines an RTCP XR block for audio quality reporting. This is intended for in-service monitoring of audio streaming, IPTV and IP videoconferencing services to provide real time performance feedback and support performance management. 5. IANA Considerations The block type "mmm" will need to be replaced with an IANA assigned number within those allocated for RTCP XR report blocks (RFC 3611). 6. Security Considerations RTCP reports can contain sensitive information since they can provide information about the nature and duration of a session established between two endpoints. As a result, any third party wishing to obtain this information should be properly authenticated and the information transferred securely. 7. Acknowledgments 8. Informative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003. Clark [Page 4] draft-ietf-avt-rtcpxr-audio-00.txt July 2007 [3] Friedman, T., Caceres, R. and A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, November 2003. Authors' Addresses Alan Clark Telchemy Incorporated 2905 Premiere Parkway, Suite 280 Duluth, GA 30097 Email: alan@telchemy.com Amy Pendleton Nortel 2380 Performance Drive Richardson, TX 75081 Email: aspen@nortel.com Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. Clark [Page 5] draft-ietf-avt-rtcpxr-audio-00.txt July 2007 The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Clark [Page 6]