draft-ietf-xrblock-rtcp-xr-post-repair-loss-count-02.txt   draft-ietf-xrblock-rtcp-xr-post-repair-loss-count-03.txt 
INTERNET-DRAFT R. Huang INTERNET-DRAFT R. Huang
Intended Status: Standard Huawei Intended Status: Standard Huawei
Expires: September 4, 2014 V. Singh Expires: October 10, 2014 V. Singh
Aalto University Aalto University
March 3, 2014 April 8, 2014
RTP Control Protocol (RTCP) Extended Report (XR) for Post-Repair RTP Control Protocol (RTCP) Extended Report (XR) for Post-Repair
Loss Count Metrics Loss Count Metrics
draft-ietf-xrblock-rtcp-xr-post-repair-loss-count-02 draft-ietf-xrblock-rtcp-xr-post-repair-loss-count-03
Abstract Abstract
This document defines an RTP Control Protocol (RTCP) Extended Report This document defines an RTP Control Protocol (RTCP) Extended Report
(XR) Block that allows reporting of post-repair loss count metrics (XR) Block that allows reporting of post-repair loss count metrics
for a range of RTP applications. for a range of RTP applications.
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
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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 . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Post-Repair Loss Count Metrics Report Block . . . . . . . . . . 4 3 Post-Repair Loss Count Metrics Report Block . . . . . . . . . . 4
4 SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1 SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 5 4.1 SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . 6
4.2 Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 6 4.2 Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . 6
5 Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5 Security Considerations . . . . . . . . . . . . . . . . . . . . 6
6 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6.1 New RTCP XR Block Type value . . . . . . . . . . . . . . . 6 6.1 New RTCP XR Block Type value . . . . . . . . . . . . . . . 6
6.2 New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 7 6.2 New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 7
6.3 Contact Information for registrations . . . . . . . . . . . 7 6.3 Contact Information for registrations . . . . . . . . . . . 7
7 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7 7 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
8 References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8 References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1 Normative References . . . . . . . . . . . . . . . . . . . 7 8.1 Normative References . . . . . . . . . . . . . . . . . . . 7
8.2 Informative References . . . . . . . . . . . . . . . . . . 7 8.2 Informative References . . . . . . . . . . . . . . . . . . 8
Appendix A. Metrics Represented Using the Template from RFC 6390 . 8 Appendix A. Metrics Represented Using the Template from RFC 6390 . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
1 Introduction 1 Introduction
RTCP SR/RR [RFC3550] contains some rough statistics about the data RTCP SR/RR [RFC3550] contains some rough statistics about the data
received from the particular source indicated in that block. One of received from the particular source indicated in that block. One of
them is the cumulative number of packet lost, which is called pre- them is the cumulative number of packet lost, which is called pre-
repair loss metric in this document. This metric conveys information repair loss metric in this document. This metric conveys information
regarding the total number of RTP data packets that have been lost regarding the total number of RTP data packets that have been lost
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specifies a post-repair loss Run-length Encoding (RLE) XR report specifies a post-repair loss Run-length Encoding (RLE) XR report
block to address this issue. The sending endpoint is able to infer block to address this issue. The sending endpoint is able to infer
which packets were repaired from the RLE report block, but at the which packets were repaired from the RLE report block, but at the
cost of higher overhead. When applications use multiple XR blocks, cost of higher overhead. When applications use multiple XR blocks,
the endpoints may require more concise reporting to save bandwidth. the endpoints may require more concise reporting to save bandwidth.
This document defines a new XR block type to augment those defined in This document defines a new XR block type to augment those defined in
[RFC3611] and complement the report block defined in [RFC5725] for [RFC3611] and complement the report block defined in [RFC5725] for
use in a range of RTP application. This new block type reports the use in a range of RTP application. This new block type reports the
number of primary source RTP packets that are still lost after number of primary source RTP packets that are still lost after
applying one or more loss repair mechanisms. When comparing this applying one or more loss repair mechanisms. The metrics defined in
metric with pre-repair loss metric of RTCP SR/RR, ambiguity may occur this document are packet level rather than slice/picture level, which
as noted in [RFC5725]: Some packets will not be repaired in current means the partial recovery of a packet will not be regarded as a
RTCP interval. Thus it is RECOMMENDED that this report block should repaired packet. When comparing this metric with pre-repair loss
be generated for those source packets that have no further chance of metric of RTCP SR/RR, ambiguity may occur as noted in [RFC5725]: Some
being repaired. But a potential ambiguity may result from sequence packets will not be repaired in current RTCP interval. Thus it is
number range inconsistent. The sequence number range reported by RTCP RECOMMENDED that this report block should be generated for those
SR/RR may contain some sequence numbers of packets for which repair source packets that have no further chance of being repaired. But a
might still be possible. To address this issue, we use begin sequence potential ambiguity may result from sequence number range
number and end sequence number to explicitly indicate the actual inconsistent. The sequence number range reported by RTCP SR/RR may
sequence number range that this RTCP XR report block reports on. In contain some sequence numbers of packets for which repair might still
addition, another metric, repaired loss count, is also introduced in be possible. To address this issue, we use begin sequence number and
this report block for calculating the pre-repair loss count during end sequence number to explicitly indicate the actual sequence number
the this range, so that the RTP sender or a third-party entity is range that this RTCP XR report block reports on. In addition,
able to evaluate the effectiveness of the repair methods used by the another metric, repaired loss count, is also introduced in this
system. Note that the metrics in this report block MUST NOT be report block for calculating the pre-repair loss count during the
directly compared with the pre-repair loss metric of [RFC3550]. this range, so that the RTP sender or a third-party entity is able to
evaluate the effectiveness of the repair methods used by the system.
Note that the metrics in this report block MUST NOT be directly
compared with the pre-repair loss metric of [RFC3550].
The metrics defined in this document belongs to the class of The metrics defined in this document belongs to the class of
transport-related metrics defined in [RFC6792]. And it is in transport-related metrics defined in [RFC6792]. And it is in
accordance with the guidelines in [RFC6390] and [RFC6792]. These accordance with the guidelines in [RFC6390] and [RFC6792]. These
metrics are applicable to any RTP application, especially those that metrics are applicable to any RTP application, especially those that
use loss repair mechanisms. use loss repair mechanisms.
2 Terminology 2 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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"RTP Control Protocol Extended Reports (RTCP XR)", "RTP Control Protocol Extended Reports (RTCP XR)",
RFC 3611, November 2003. RFC 3611, November 2003.
[RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE [RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE
Report Block Type for RTP Control Protocol (RTCP) Extended Report Block Type for RTP Control Protocol (RTCP) Extended
Reports (XRs)", RFC 5725, February 2010. Reports (XRs)", RFC 5725, February 2010.
[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.
[RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
July 2006.
[RFC5109] Li, A., Ed., "RTP Payload Format for Generic Forward Error
Correction", RFC 5109, December 2007.
8.2 Informative References 8.2 Informative References
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development", BCP 170, RFC 6390, Performance Metric Development", BCP 170, RFC 6390,
October 2011. October 2011.
[RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the [RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
RTP Monitoring Framework", RFC 6792, November 2012. RTP Monitoring Framework", RFC 6792, November 2012.
Appendix A. Metrics Represented Using the Template from RFC 6390 Appendix A. Metrics Represented Using the Template from RFC 6390
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