RTP Control Protocol (RTCP) Extended Report (XR) for Post-Repair Loss Count Metrics
RFC 7509
Document | Type | RFC - Proposed Standard (May 2015; No errata) | |
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Authors | Rachel Huang , Varun Singh | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Dan Romascanu | ||
Shepherd write-up | Show (last changed 2014-12-02) | ||
IESG | IESG state | RFC 7509 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Alissa Cooper | ||
Send notices to | (None) | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) R. Huang Request for Comments: 7509 Huawei Category: Standards Track V. Singh ISSN: 2070-1721 Aalto University May 2015 RTP Control Protocol (RTCP) Extended Report (XR) for Post-Repair Loss Count Metrics Abstract This document defines an RTP Control Protocol (RTCP) Extended Report (XR) block that allows reporting of a post-repair loss count metric for a range of RTP applications. In addition, another metric, repaired loss count, is also introduced in this report block for calculating the pre-repair loss count when needed, so that the RTP sender or a third-party entity is able to evaluate the effectiveness of the repair methods used by the system. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7509. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Singh & Huang Standards Track [Page 1] RFC 7509 Post-Repair Non-RLE Loss Count May 2015 Table of Contents 1. Introduction ....................................................2 2. Terminology .....................................................3 3. Post-Repair Loss Count Metrics Report Block .....................3 3.1. Report Block Structure .....................................4 3.2. Example Usage ..............................................5 4. SDP Signaling ...................................................6 4.1. SDP rtcp-xr-attrib Attribute Extension .....................6 4.2. Offer/Answer Usage .........................................7 5. Security Considerations .........................................7 6. IANA Considerations .............................................7 6.1. New RTCP XR Block Type Value ...............................7 6.2. New RTCP XR SDP Parameter ..................................7 6.3. Contact Information for Registrations ......................7 7. References ......................................................8 7.1. Normative References .......................................8 7.2. Informative References .....................................9 Appendix A. Metrics Represented Using the Template from RFC 6390 ..10 Acknowledgments ...................................................11 Authors' Addresses ................................................11 1. Introduction RTCP Sender Reports (SRs) / Receiver Reports (RRs) [RFC3550] contain some rough statistics about the data received from the particular source indicated in that block. One of them is the cumulative number of packets lost, which is called the pre-repair loss metric in this document. This metric conveys information regarding the total number of RTP data packets that have been lost since the beginning of the RTP session. However, this metric is measured on the media stream before any loss- repair mechanism, e.g., retransmission [RFC4588] or Forward Error Correction (FEC) [RFC5109], is applied. Using a repair mechanism usually results in recovering some or all of the lost packets. The recovery process does not reduce the values reported by the two loss metrics in RTCP RR [RFC3550] -- namely, the fraction lost and the cumulative loss. Hence, the sending endpoint cannot infer the performance of the repair mechanism based on the aforementioned metrics in [RFC3550]. Consequently, [RFC5725] specifies a post-repair loss Run-Length Encoding (RLE) XR report block to address this issue. The sending endpoint is able to infer which packets were repaired from the RLEShow full document text