XR Block Working Group J. Ott Internet-Draft V.
SinghSingh, Ed. Intended status: Standards Track Aalto University Expires: January 06,April 04, 2014 I. Curcio Nokia Research Center July 05,October 01, 2013 RTP Control Protocol (RTCP) Extended ReportsReport (XR) for Run Length Encoding (RLE) of Discarded Packets draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-06.txtdraft-ietf-xrblock-rtcp-xr-discard-rle-metrics-07 Abstract The RTP Control Protocol (RTCP) is used in conjunction with the Real- time Transport Protocol (RTP) in to provide a variety of short-term and long-term reception statistics. The available reporting may include aggregate information across longer periods of time as well as individual packet reporting. This document specifies a per-packet report metric capturing individual packets discarded from the de- jitter buffer after successful reception. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on January 06,April 04, 2014. Copyright Notice Copyright (c) 2013 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. XR Discard RLE Report Block . . . . . . . . . . . . . . . . . 4 4. XR Bytes Discarded Report Block . . . . . . . . . . . . . . . 5 5.Protocol Operation . . . . . . . . . . . . . . . . . . . . . 7 5.1.5 4.1. Reporting Node (Receiver) . . . . . . . . . . . . . . . . 7 5.2.5 4.2. Media Sender . . . . . . . . . . . . . . . . . . . . . . 7 6.6 5. SDP signaling . . . . . . . . . . . . . . . . . . . . . . . . 7 7.6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 8.7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 8.1.7 7.1. XR Report Block Registration . . . . . . . . . . . . . . 8 8.2.7 7.2. SDP Parameter Registration . . . . . . . . . . . . . . . 8 8.3.7 7.3. Contact information for IANA registrations . . . . . . . 9 9.8 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 10.8 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 10.1.8 9.1. Normative References . . . . . . . . . . . . . . . . . . 9 10.2.8 9.2. Informative References . . . . . . . . . . . . . . . . . 108 Appendix A. Metrics represented using RFC6390 Template . . . . . 9 Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 10 A.1.B.1. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-00 . . . . . . . . . . . . . . . . . . . . . . . 10 A.2.B.2. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-01 . . . . . . . . . . . . . . . . . . . . . . . 10 A.3.B.3. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-02 . . . . . . . . . . . . . . . . . . . . . . . 10 A.4.B.4. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-03 . . . . . . . . . . . . . . . . . . . . . . . 10 A.5.B.5. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-04 . . . . . . . . . . . . . . . . . . . . . . . 10 A.6.11 B.6. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-05 . . . . . . . . . . . . . . . . . . . . . . . 11 B.7. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-06 . . . . . . . . . . . . . . . . . . . . . . . 11 B.8. changes in draft-ietf-xrblock-rtcp-xr-discard-rle- metrics-07 . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 1. Introduction RTP [RFC3550] provides a transport for real-time media flows such as audio and video together with the RTP control protocol (RTCP) which provides periodic feedback about the media streams received in a specific duration. In addition, RTCP can be used for timely feedback about individual events to report (e.g., packet loss) [RFC4585]. Both long-term and short-term feedback enable a media sender to adapt its media transmission and/or encoding dynamically to the observed path characteristics. RFC3611 [RFC3611] defines RTCP Extended Reports as a detailed reporting framework to provide more than just the coarse RRReceiver Report (RR) statistics. The detailed reporting may enable a media sender to react more appropriately to the observed networking conditions as these can be characterized better, although at the expense of extra overhead. Among many other report blocks, RFC3611 specifies the Loss Run Length Encoding (RLE) block which reports runs of packets received and lost with the granularity of individual packets. This can help both error recovery and path loss characterization. In addition to lost packets, RFC3611 defines the notion of "discarded" packets: packets that were received but dropped from the jitterde-jitter buffer because they were either too early (for buffering) or too late (for playout). The "discard rate" metric is part of the VoIP metrics report block even though it is not just applicable to audio: it is specified as the fraction of discarded packets since the beginning of the session. See section 4.7.1 of RFC3611 [RFC3611]. The discard metric is believed to be applicable to a large class of RTP applications which use a de-jitter buffer RFC5481 [RFC5481]. Recently proposed extensions to the Extended Reports (XR) reporting suggest enhancing this discard metric: o Reporting the number of discarded packets in a measurement interval, i.e., during either the last reporting interval or since the beginning of the session, as indicated by a flag in the suggested XR report [I-D.ietf-xrblock-rtcp-xr-discard]. If an endpoint needs to report packet discard due to other reasons than early- and late-arrival (for example, discard due to duplication, redundancy, etc.) then it should consider using the Discarded Packets Report Block [I-D.ietf-xrblock-rtcp-xr-discard]. o Reporting gaps and bursts of discarded packets during a measurement interval, i.e., the last reporting interval or the duration of the session [I-D.ietf-xrblock-rtcp-xr-burst-gap-discard]. o Reporting the sum of payload bytes discarded during a measurement interval, i.e., the last reporting interval or the duration of the session [I-D.singh-xrblock-rtcp-xr-bytes-discarded-metric]. However, none of these metrics allow a receiver to report precisely which packets were discarded. While this information could in theory be derived from high-frequency reporting on the number of discarded packets [I-D.ietf-xrblock-rtcp-xr-discard] or from the gap/burst report [I-D.ietf-xrblock-rtcp-xr-burst-gap-discard], these two mechanisms do not appear feasible: The former would require an unduly high amount of reporting which still might not be sufficient due to the non-deterministic scheduling of RTCP packets. The latter incur significant complexity and reporting overhead and might still not deliver the desired accuracy. This document defines a discard report block following the idea of the run-length encoding applied for lost and received packets in [RFC3611]. Complementary to or instead of the indication which packets were discarded, an XR block is defined to indicate the number of bytes discarded, per interval or for the duration of the session, similar to other XR report blocks.2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, RFC 2119 [RFC2119] and indicate requirement levels for compliant implementations.[RFC2119]. The terminology defined in RTP [RFC3550] and in the extensions for XR reporting [RFC3611] applies. 3. XR Discard RLE Report Block The XR Discard RLE report block uses the same format as specified for the loss and duplicate report blocks in [RFC3611]. Figure 1 describes the packet format. The fields "BT", "T", "block length", "SSRC of source", "begin_seq", and "end_seq" SHALLhave the same semantics and representation as defined in [RFC3611].[RFC3611], with the addition of the "E" flag to indicate the reason for discard. The "chunks" encoding the run length SHALLhave the same representation as in RFC3611, but encode discarded packets. A definition of a discarded packet is given in [I-D.ietf-xrblock-rtcp-xr-discard]. 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=DRLE |rsvd |E| T | block length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSRC of source | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | begin_seq | end_seq | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | chunk 1 | chunk 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ : ... : +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | chunk n-1 | chunk n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: XR Discard RLE Report Block Block Type (BT, 8 bits): A Run-length encoded Discarded Packets Report Block is identified by the constant DRLE. [Note to RFC Editor: please replace DRLE with the IANA provided RTCP XR block type for this block. Please remove this note prior to publication as an RFC.] rsvd (3 bits): TheseThis field is reserved for future definition. In the absence of such definition, the bits SHOULDin this field MUST be set to zero by receiversand MUST be ignored by senders.the receiver. The 'E' bit is introduced to distinguish between packets discarded due to early arrival and those discarded due to late arrival. The 'E' bit MUST beis set to '1' if the chunks represent packets discarded due to too early arrival and MUST beis set to '0' otherwise. In case both early and late discarded packets shall be reported, two Discard RLE report blocks MUST be included; their sequence number range MAY overlap, but individual packets MUST only be reported as either early or late and not appear marked in both. Packets reported in neither are considered to be properly received and not discarded. Discard RLE Report Blocks SHOULD be sent in conjunction with an RTCP RR as a compound RTCP packet. 4. XR Bytes Discarded Report Block The XR Bytes Discarded report block uses the following format which follows the model of the framework for performance metric development [RFC6390]. 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=BDR | I |E|reserved | block length=2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SSRC of source | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | number of bytes discarded | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: XR Bytes Discarded Report Block Block Type (BT, 8 bits): A Bytes Discarded Packets Report Block is identified by the constant BDR. [Note to RFC Editor: please replace BDR with the IANA provided RTCP XR block type for this block. Please remove this note prior to publication as an RFC.] The Interval Metric flag (I) (2 bits) is used to indicate whether the discard metric is Interval, or a Cumulative metric, that is, whether the reported value applies to the most recent measurement interval duration between successive reports (I=10, the Interval Duration) or to the accumulation period characteristic of cumulative measurements (I=11, the Cumulative Duration). Since the bytes discarded are not measured at a particular time instance but over one or several reporting intervals, the metric MUST NOT be reported as a Sampled Metric (I=01). The 'E' bit is introduced to distinguish between packets discarded due to early arrival and those discarded due to late arrival. The 'E' bit MUST be set to '1' if it reports bytes discarded due to early arrival and MUST be set to '0' if it reports bytes discarded due to late arrival. In case both early and late discarded packets shall be reported, two Bytes Discarded report blocks MUST be included. These reserved bits (5 bits) SHOULD be set to zero by receivers and MUST be ignored by senders. block length (16 bits) MUST be set to 2, in accordance with the definition of this field in [RFC3611]. The block MUST be discarded if the block length is set to a different value. The 'number of bytes discarded' is a 32-bit unsigned integer value indicating the total number of bytes discarded. If Interval Metric flag (I=11) is set, the value in the field indicates the number of bytes discarded from the start of the session, if Interval Metric flag (I=01) is set, it indicates the number of bytes discarded since the last RTCP XR Byte Discarded Block was received. If the XR block follows a measurement identity block [RFC6776] in the same RTCP compound packet then the cumulative (I=11) or the interval (I=10) for thisIf packets appear in both report block corresponds to the values ofblocks, the "measurement duration"conflicting packets are ignored. Packets reported in the measurement information block. If the receiver sends the Bytes Discardedneither are considered to be properly received and not discarded. Discard RLE Report Block without the measurement identity block then the discard block MUSTBlocks SHOULD be sent in conjunction with an RTCP Receiver Report (RR)RR as a compound RTCP packet. 5.4. Protocol Operation This section describes the behavior of the reporting node (= media receiver) nodeand the media sender. 184.108.40.206. Reporting Node (Receiver) Transmission of RTCP XR Discard RLE Reports is up to the discretion of the media receiver, as is the reporting granularity. However, it is RECOMMENDED that the media receiver signals all discarded packets using the method defined in this document. If all packets over a reporting period were lost,discarded, the media receiver MAY use the Discard Report Block [I-D.ietf-xrblock-rtcp-xr-discard] instead. In case of limited available reporting bandwidth, it is up to the receiver whether or not to include RTCP XR Discard RLE reports. The media receiver MAY send the Discard RLE Reports as part of the regularly scheduled RTCP packets as per RFC3550. It MAY also include Discard RLE Reports in immediate or early feedback packets as per RFC4585. 220.127.116.11. Media Sender The media sender MUST be prepared to operate without receiving any Discard RLE reports. If Discard RLE reports are generated by the media receiver, the media sender cannot rely on all these reports being received, nor can the media sender rely on a regular generation pattern from the receiver side.media receiver. However, if the media sender receives any RTCP reports but no Discard RLE report blocks and is aware that the media receiver supports Discard RLE report blocks, it MAY assume that no packets were discarded at the media receiver. The sender SHOULD accept the Bytes Discarded Report Block only if it is received in a compound RTCP receiver report or if it is preceded by a measurement identity block [RFC6776]. Under all other circumstances it MUST ignore the block. 6.5. SDP signaling A participant of a media session MAY use SDP to signal its support for the tworeport blocksblock specified in this document or use them without any prior signaling (see section 5 of [RFC3611]). For signaling in SDP, the RTCP XR attribute as defined in [RFC3611] MUST be used. The SDP [RFC4566] attribute 'xr-format' defined in RFC3611 is augmented as described in the following to indicate the RLEthe discard metric and bytes discardedRLE metric. rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF ; defined in [RFC3611] xr-format =/ xr-discard-rle / xr-discard-bytesxr-discard-rle = "discard-rle" xr-discard-bytes = "discard-bytes"The parameter 'discard-rle' MUST beis used to indicate support for the Discard RLE Report Block defined in Section 3, the parameter 'discard-bytes' to indicate support for the Bytes Discarded Report Block defined in Section 43. When SDP is used in Offer/Answer context, the mechanism defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters applies (see section 5.2 of [RFC3611]). 7.6. Security Considerations The Discard RLE block provides per-packet statistics so the risk to confidentiality documented in Section 7, paragraph 3 of [RFC3611] applies. In some situations, returning very detailed error information (e.g., over-range measurement or measurement unavailable) using this report block can provide an attacker with insight into the security processing. Implementers should consider the guidance in [I-D.ietf-avt-srtp-not-mandatory] for using appropriate security mechanisms, i.e., where security is a concern, the implementation should apply encryption and authentication to the report block. For example this can be achieved by using the AVPF profile together with the Secure RTP profile as defined in [RFC3711]; an appropriate combination of the two profiles (an "SAVPF") is specified in [RFC5124]. However, other mechanisms also exist (documented in [I-D.ietf-avtcore-rtp-security-options]) and might be more suitable. Additionally, The security considerations of [RFC3550], [RFC3611], and [RFC4585] apply. Since this document offers only a more precise reporting for an already existing metric, no further security implications are foreseen. 8.7. IANA Considerations New block types for RTCP XR are subject to IANA registration. For general guidelines on IANA considerations for RTCP XR, refer to [RFC3611]. 18.104.22.168. XR Report Block Registration This document extends the IANA "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry" by twoa new values:value: DRLE and BDR.(Discard RLE Report). [Note to RFC Editor: please replace DRLE and BDRwith the IANA provided RTCP XR block type for this block here and in the diagrams above. Please remove this note prior to publication as an RFC.] 22.214.171.124. SDP Parameter Registration This document registers twoa new parameters for the Session Description Protocol (SDP), "discard-rle" and "discard-bytes",in the "RTP Control Protocol Extended Reports (RTCP XR) Session Description Protocol (SDP) Parameters Registry". 126.96.36.199. Contact information for IANA registrations Joerg Ott (email@example.com) Aalto University Comnet, Otakaari 5A, 02150 Espoo, Finland. 9.8. Acknowledgments ThanksThe authors would like to Qin Wu,thank Alan Clark, Roni Even, Sam Hartman, Colin Perkins, Dan Romascanu, Roni Even andDan WingWing, and Qin Wu for providing valuable feedback on earlier versions of this draft 10.draft. 9. References 10.1.9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003. [RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, November 2003. [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, "Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July 2006. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006. [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New Performance Metric Development", BCP 170, RFC 6390, October 2011. [RFC6776] Clark, A. and Q. Wu, "Measurement Identity and Information Reporting Using a Source Description (SDES) Item and an RTCP Extended Report (XR) Block", RFC 6776, October 2012. 10.2. Informative References[I-D.ietf-xrblock-rtcp-xr-discard] Clark, A., Zorn, G., and W. Wu, "RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count metric Reporting", draft-ietf-xrblock-rtcp-xr-discard-15 (work in progress), June 2013. 9.2. Informative References [I-D.ietf-xrblock-rtcp-xr-burst-gap-discard] Clark, A., Huang, R., and W. Wu, "RTP Control Protocol(RTCP) Extended Report (XR) Block for Burst/Gap Discard metric Reporting", draft-ietf-xrblock-rtcp-xr- burst-gap-discard-14 (work in progress), April 2013. [RFC5481] Morton, A. and B. Claise, "Packet Delay Variation Applicability Statement", RFC 5481, March 2009. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004. [RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, February 2008. [I-D.ietf-avt-srtp-not-mandatory] Perkins, C. and M. Westerlund, "Securing the RTP Protocol Framework: Why RTP Does Not Mandate a Single Media Security Solution", draft-ietf-avt-srtp-not-mandatory-13 (work in progress), May 2013. [I-D.ietf-avtcore-rtp-security-options] Westerlund, M. and C. Perkins, "Options for Securing RTP Sessions", draft-ietf-avtcore-rtp-security-options-04 (work in progress), July 2013. [I-D.singh-xrblock-rtcp-xr-bytes-discarded-metric] Singh, V., Ott, J., and I. Curcio, "RTP Control Protocol (RTCP) Extended Reports (XR) for Bytes Discarded Metric", draft-singh-xrblock-rtcp-xr-bytes-discarded-metric-00 (work in progress), August 2013. Appendix A. Metrics represented using RFC6390 Template RFC EDITOR NOTE: please change XXXX in [RFCXXXX] by the new RFC number, when assigned. a. Run-length encoding (RLE) of Discarded Packets Metric * Metric Name: Discard Run-length encoding Metric * Metric Description: Instances of packets discarded over the period covered by this report. * Method of Measurement or Calculation: See section 3, for the definition of Discard RLE [RFCXXXX] and section 4.1 of RFC3611 for Run-length encoding. * Units of Measurement: Every packet in the interval is reported as discarded or not. See section 3 for the definition of Discard RLE [RFCXXXX]. * Measurement Point(s) with Potential Measurement Domain: The measurement of these metrics is made at the receiving end of the RTP stream. * Measurement Timing: Each packet between a beginning sequence number (begin_seq) and ending sequence number (end_seq) are reported as discarded or not. See section 3 for the definition of Discard RLE [RFCXXXX]. * Use and applications: See section 1, paragraph 1 of [RFCXXXX]. * Reporting model: See RFC3611. Appendix B. Change Log Note to the RFC-Editor: please remove this section prior to publication as an RFC. A.1.B.1. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-00 o Changed the interval flag from 1 to 2 bits in the discarded bytes report. Also added the measurement identification tag to the block. o Added this section. A.2.B.2. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-01 o Removed the measurement identification tag in the bytes discarded block. A.3.B.3. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-02 o Removed the extra Tag bits from the Discarded bytes XR block. o Clarified use of measurement identity block in Section 4 and 5.2 A.4.B.4. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-03 o Added explanation for block length in bytes discarded block. o Added an acknowledgement section. A.5.B.5. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-04 o Added Block Type definition to each XRBlock. o Made changes requested in WGLC. A.6.B.6. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-05 o Made changes requested by SDP directorate. B.7. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-06 o Editorial fixes based on review from Gen-art and IESG review. B.8. changes in draft-ietf-xrblock-rtcp-xr-discard-rle-metrics-07 o Editorial fixes based on review from IESG. o Editorial fixes based on Security and PM directorate. o Split bytes discarded from this draft to another. o Updated Security Considerations Section. o This draft now normatively cites the definition of discards in 'packets discarded' draft. Authors' Addresses Joerg Ott Aalto University School of Electrical Engineering Otakaari 5 A Espoo, FIN 02150 Finland Email: firstname.lastname@example.org Varun Singh (editor) Aalto University School of Electrical Engineering Otakaari 5 A Espoo, FIN 02150 Finland Email: email@example.com URI: http://www.netlab.tkk.fi/~varun/ Igor D.D. Curcio Nokia Research Center P.O. Box 1000 (Visiokatu 3) Tampere, FIN 33721 Finland Email: firstname.lastname@example.org