Internet Engineering Task Force (IETF) J. Ott
Request for Comments: 7097 V. Singh, Ed.
Category: Standards Track Aalto University
ISSN: 2070-1721 I. Curcio
Nokia Research Center
January 2014
Internet Engineering Task Force (IETF) J. Ott
Request for Comments: 7097 V. Singh, Ed.
Category: Standards Track Aalto University
ISSN: 2070-1721 I. Curcio
Nokia Research Center
January 2014
RTP Control Protocol (RTCP) Extended Report (XR) for RLE of Discarded Packets
用于丢弃数据包的RLE的RTP控制协议（RTCP）扩展报告（XR）
Abstract
摘要
The RTP Control Protocol (RTCP) is used in conjunction with the Real-time Transport Protocol (RTP) in order 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.
RTP控制协议（RTCP）与实时传输协议（RTP）结合使用，以提供各种短期和长期接收统计数据。可用的报告可以包括跨较长时间段的聚合信息以及单个分组报告。本文档指定了一个每个数据包报告指标，用于捕获成功接收后从去抖动缓冲区丢弃的各个数据包。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
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.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 5741第2节。
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/rfc7097.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc7097.
Copyright Notice
版权公告
Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2014 IETF信托基金和确定为文件作者的人员。版权所有。
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.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction ....................................................3
2. Terminology .....................................................4
3. RTCP XR Discard RLE Report Block ................................4
4. Protocol Operation ..............................................6
4.1. Reporting Node (Receiver) ..................................6
4.2. Media Sender ...............................................6
5. SDP Signaling ...................................................6
6. Security Considerations .........................................7
7. IANA Considerations .............................................7
7.1. XR Report Block Registration ...............................7
7.2. SDP Parameter Registration .................................8
7.3. Contact Information for IANA Registrations .................8
8. Acknowledgments .................................................8
9. References ......................................................8
9.1. Normative References .......................................8
9.2. Informative References .....................................9
Appendix A. Metrics Represented Using the Template from RFC 6390 ..10
1. Introduction ....................................................3
2. Terminology .....................................................4
3. RTCP XR Discard RLE Report Block ................................4
4. Protocol Operation ..............................................6
4.1. Reporting Node (Receiver) ..................................6
4.2. Media Sender ...............................................6
5. SDP Signaling ...................................................6
6. Security Considerations .........................................7
7. IANA Considerations .............................................7
7.1. XR Report Block Registration ...............................7
7.2. SDP Parameter Registration .................................8
7.3. Contact Information for IANA Registrations .................8
8. Acknowledgments .................................................8
9. References ......................................................8
9.1. Normative References .......................................8
9.2. Informative References .....................................9
Appendix A. Metrics Represented Using the Template from RFC 6390 ..10
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.
RTP[RFC3550]与RTP控制协议（RTCP）一起为实时媒体流（如音频和视频）提供传输，RTP控制协议（RTCP）提供关于在特定持续时间内接收的媒体流的定期反馈。此外，RTCP可用于及时反馈要报告的单个事件（例如，数据包丢失）[RFC4585]。长期和短期反馈使媒体发送者能够根据观察到的路径特征动态地调整其媒体传输和/或编码。
RFC 3611 [RFC3611] defines RTCP Extended Reports as a detailed reporting framework to provide more than just the coarse Receiver 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.
RFC 3611[RFC3611]将RTCP扩展报告定义为一个详细的报告框架，提供的不仅仅是粗略的接收器报告（RR）统计数据。详细报告可以使媒体发送者能够对观察到的网络条件作出更适当的反应，因为这些条件可以被更好地描述，尽管以额外开销为代价。
Among many other report blocks, RFC 3611 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, RFC 3611 defines the notion of "discarded" packets: packets that were received but dropped from the de-jitter buffer because they were either too early (for buffering) or too late (for playout). The "discard rate" metric is part of the Voice over IP (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 RFC 3611 [RFC3611]). The discard metric is believed to be applicable to a large class of RTP applications that use a de-jitter buffer [RFC5481].
在许多其他报告块中，RFC 3611指定了丢失游程编码（RLE）块，该块报告接收到的和丢失的数据包的运行情况以及各个数据包的粒度。这有助于错误恢复和路径损耗特性描述。除了丢失的数据包外，RFC 3611还定义了“丢弃”数据包的概念：接收到的数据包由于太早（用于缓冲）或太晚（用于播放）而从去抖动缓冲区丢弃。“丢弃率”指标是IP语音（VoIP）指标报告块的一部分，尽管它不仅适用于音频：它被指定为自会话开始以来丢弃的数据包的分数（参见RFC 3611[RFC3611]第4.7.1节）。丢弃度量被认为适用于使用去抖动缓冲器[RFC5481]的一大类RTP应用程序。
Recently proposed extensions to the Extended Reports (XRs) reporting suggest enhancing this discard metric:
最近提出的扩展报告（XRs）报告的扩展建议加强这一丢弃指标：
o Reporting the number of discarded packets in a measurement interval, i.e., either during the last reporting interval or since the beginning of the session, as indicated by a flag in the suggested XR [RFC7002]. If an endpoint needs to report packet discard due to reasons other than early and late arrival (for example, discard due to duplication, redundancy, etc.), then it should consider using the Discarded Packets report block [RFC7002].
o 报告测量间隔内丢弃数据包的数量，即在最后一个报告间隔期间或自会话开始以来，如建议的XR[RFC7002]中的标志所示。如果一个端点需要报告由于早和迟到达的原因而丢弃的报文丢弃（例如，由于重复、冗余等而丢弃），那么它应该考虑使用丢弃的数据包报告块[RCF702]。
o Reporting gaps and bursts of discarded packets during a measurement interval, i.e., the last reporting interval or the duration of the session [RFC7003].
o 在测量间隔（即最后一个报告间隔或会话持续时间）期间报告丢弃数据包的间隔和突发[RFC7003]。
o Reporting the sum of payload bytes discarded during a measurement interval, i.e., the last reporting interval or the duration of the session [DISCARD-METRIC].
o 报告在测量间隔期间丢弃的有效负载字节总数，即最后一个报告间隔或会话持续时间[DISCARD-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 [RFC7002] or from the gap/burst report [RFC7003], 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 incurs significant complexity and reporting overhead and might still not deliver the desired accuracy.
然而，这些指标都不允许接收者精确地报告丢弃了哪些数据包。虽然理论上可以从丢弃数据包数量的高频报告[RFC7002]或从间隙/突发报告[RFC7003]中得出此信息，但这两种机制似乎不可行：前者需要过高的报告量，由于RTCP数据包的非确定性调度，这可能仍然不够。后者会带来巨大的复杂性和报告开销，并且可能仍然无法提供所需的准确性。
This document defines a discard report block following the idea of the run-length encoding applied for lost and received packets in [RFC3611].
本文档根据[RFC3611]中应用于丢失和接收数据包的运行长度编码的思想，定义了丢弃报告块。
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].
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照BCP 14、RFC 2119[RFC2119]中的说明进行解释。
The terminology defined in RTP [RFC3550] and in the extensions for XR reporting [RFC3611] applies.
RTP[RFC3550]和XR报告扩展[RFC3611]中定义的术语适用。
The RTCP XR Discard RLE report block uses the same format as specified for the loss and duplicate report blocks in RFC 3611 [RFC3611]. Figure 1 describes the packet format. The fields "BT", "T", "block length", "SSRC of source", "begin_seq", and "end_seq" have the same semantics and representation as defined in [RFC3611], with the addition of the "E" flag to indicate the reason for discard. The "chunks" encoding the run length have the same representation as in RFC 3611, but encode discarded packets. A definition of a discarded packet is given in RFC 7002 [RFC7002].
RTCP XR Discard RLE报告块使用与RFC 3611[RFC3611]中为丢失和重复报告块指定的格式相同的格式。图1描述了数据包格式。字段“BT”、“T”、“块长度”、“源的SSRC”、“开始顺序”和“结束顺序”具有与[RFC3611]中定义的相同的语义和表示，并添加了“E”标志以指示丢弃的原因。编码游程长度的“块”具有与RFC3611中相同的表示，但编码丢弃的数据包。RFC 7002[RFC7002]中给出了丢弃数据包的定义。
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=25 |rsvd |E| T | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| chunk 1 | chunk 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| chunk n-1 | chunk n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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=25 |rsvd |E| T | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| chunk 1 | chunk 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| chunk n-1 | chunk n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: RTCP XR Discard RLE Report Block
图1:RTCP XR Discard RLE报告块
Block Type (BT, 8 bits): A Discard RLE report block is identified by the constant 25.
块类型（BT，8位）：丢弃RLE报告块由常数25标识。
rsvd (3 bits): This field is reserved for future definition. In the absence of such definition, the bits in this field MUST be set to zero and MUST be ignored by the receiver.
rsvd（3位）：此字段保留供将来定义。在没有这种定义的情况下，此字段中的位必须设置为零，并且必须被接收器忽略。
The 'E' bit is introduced to distinguish between packets discarded due to early arrival and those discarded due to late arrival. The 'E' bit is set to '1' if the chunks represent packets discarded due to arriving too early and is set to '0' otherwise.
引入“E”位以区分由于提前到达而丢弃的数据包和由于延迟到达而丢弃的数据包。如果数据块表示由于过早到达而丢弃的数据包，“E”位设置为“1”，否则设置为“0”。
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. If packets appear in both report blocks, the conflicting packets will be ignored. Packets not reported in either block are considered to be properly received and not discarded.
如果同时报告早期和晚期丢弃的数据包，则必须包括两个丢弃RLE报告块；它们的序列号范围可能重叠，但单个数据包只能报告为早或晚，并且不能同时显示为标记。如果数据包出现在两个报告块中，则冲突的数据包将被忽略。两个块中均未报告的数据包被视为已正确接收且未被丢弃。
Discard RLE report blocks SHOULD be sent in conjunction with an RTCP RR as a compound RTCP packet.
丢弃RLE报告块应与RTCP RR一起作为复合RTCP数据包发送。
This section describes the behavior of the reporting node (= media receiver) and the media sender.
本节介绍报告节点（=媒体接收器）和媒体发送者的行为。
Transmission of RTCP XR Discard RLE report blocks is up to the discretion of the media receiver, as is the reporting granularity. However, it is RECOMMENDED that the media receiver signal all discarded packets using the method defined in this document. If all packets over a reporting period are discarded, the media receiver MAY use the Discard Report Block [RFC7002] instead. In case of limited available reporting bandwidth, it is up to the receiver whether or not to include RTCP XR Discard RLE report blocks.
RTCP XR Discard RLE报告块的传输由媒体接收器决定，报告粒度也是如此。但是，建议媒体接收器使用本文档中定义的方法向所有丢弃的数据包发送信号。如果报告期间的所有数据包都被丢弃，则媒体接收器可以使用丢弃报告块[RFC7002]。在可用报告带宽有限的情况下，是否包括RTCP XR Discard RLE报告块取决于接收器。
The media receiver MAY send the Discard RLE report blocks as part of the regularly scheduled RTCP packets, as per RFC 3550. It MAY also include Discard RLE report blocks in immediate or early feedback packets, as per RFC 4585.
根据RFC 3550，媒体接收器可将丢弃RLE报告块作为定期调度的RTCP分组的一部分发送。根据RFC 4585，它还可以包括在即时或早期反馈包中丢弃RLE报告块。
The media sender MUST be prepared to operate without receiving any Discard RLE report blocks. If Discard RLE report blocks 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 media receiver.
媒体发送器必须准备好在不接收任何丢弃RLE报告块的情况下运行。如果丢弃RLE报告块是由媒体接收器生成的，则媒体发送器不能依赖于接收到的所有这些报告，媒体发送器也不能依赖于来自媒体接收器的常规生成模式。
However, if the media sender receives RTCP XR reports but the reports contain 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.
但是，如果媒体发送方接收到RTCP XR报告，但该报告不包含丢弃的RLE报告块，并且知道媒体接收方支持丢弃的RLE报告块，则可能认为媒体接收方未丢弃任何数据包。
A participant of a media session MAY use SDP to signal its support for the report block specified in this document or use them without any prior signaling (see Section 5 of RFC 3611 [RFC3611]).
媒体会话的参与者可以使用SDP来表示其支持本文档中指定的报告块，也可以在没有任何事先信号的情况下使用SDP（参见RFC 3611[RFC3611]第5节）。
For signaling in SDP, the RTCP XR attribute as defined in RFC 3611 [RFC3611] MUST be used. The SDP [RFC4566] attribute 'xr-format' defined in RFC 3611 is augmented as described in the following to indicate the discard RLE metric.
对于SDP中的信令，必须使用RFC 3611[RFC3611]中定义的RTCP XR属性。RFC 3611中定义的SDP[RFC4566]属性“xr format”按如下所述进行扩充，以指示丢弃RLE度量。
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)]
CRLF ; defined in [RFC3611]
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)]
CRLF ; defined in [RFC3611]
xr-format =/ xr-discard-rle
xr format=/xr discard rle
xr-discard-rle = "discard-rle"
xr-discard-rle = "discard-rle"
The parameter 'discard-rle' is used to indicate support for the Discard RLE report block defined in Section 3.
参数“discard rle”用于表示对第3节中定义的discard rle报告块的支持。
When SDP is used in Offer/Answer context, the mechanism defined in RFC 3611 [RFC3611] for unilateral "rtcp-xr" attribute parameters applies (see Section 5.2 of RFC 3611 [RFC3611]).
在报价/应答上下文中使用SDP时，RFC 3611[RFC3611]中定义的单边“rtcp xr”属性参数机制适用（参见RFC 3611[RFC3611]第5.2节）。
The Discard RLE report block provides per-packet statistics so the risk to confidentiality documented in Section 7, Paragraph 3, of RFC 3611 [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 [NO-SRTP] 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 RFC 3711 [RFC3711]; an appropriate combination of the two profiles (an "SAVPF") is specified in RFC 5124 [RFC5124]. However, other mechanisms also exist [SRTP-OPTIONS] and might be more suitable.
丢弃RLE报告块提供每个数据包的统计信息，因此RFC 3611[RFC3611]第7节第3段中记录的保密风险适用。在某些情况下，使用此报告块返回非常详细的错误信息（例如，超范围测量或测量不可用）可以让攻击者深入了解安全处理。实现者应该考虑[NO-SRTP ]中使用适当的安全机制的指导，即在安全性关注的地方，实现应该对报告块应用加密和认证。例如，这可以通过将AVPF配置文件与RFC 3711[RFC3711]中定义的安全RTP配置文件一起使用来实现；RFC 5124[RFC5124]中规定了两个配置文件的适当组合（“SAVPF”）。然而，也存在其他机制[SRTP-OPTIONS]，可能更合适。
Additionally, The security considerations of RFC 3550 [RFC3550], RFC 3611 [RFC3611], and RFC 4585 [RFC4585] apply.
此外，RFC 3550[RFC3550]、RFC 3611[RFC3611]和RFC 4585[RFC4585]的安全注意事项也适用。
New block types for RTCP XR are subject to IANA registration. For general guidelines on IANA considerations for RTCP XR, refer to RFC 3611.
RTCP XR的新块类型需要IANA注册。有关RTCP XR的IANA注意事项的一般指南，请参阅RFC 3611。
This document extends the IANA "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry" by assigning value 25 to DRLE (Discard RLE Report).
本文档通过将值25分配给DRLE（放弃RLE报告），扩展IANA“RTP控制协议扩展报告（RTCP XR）块类型注册表”。
This document registers 'discard-rle' in the "RTCP XR SDP Parameters".
本文档在“RTCP XR SDP参数”中注册“放弃rle”。
Joerg Ott (jo@comnet.tkk.fi)
约格奥特(jo@comnet.tkk.fi)
Aalto University Comnet, Otakaari 5A, 02150 Espoo, Finland.
芬兰埃斯波奥塔卡里5A奥尔托大学通信网，邮编：02150。
The authors would like to thank Alan Clark, Roni Even, Sam Hartman, Colin Perkins, Dan Romascanu, Dan Wing, and Qin Wu for providing valuable feedback on earlier draft versions of this document.
作者要感谢Alan Clark、Roni Even、Sam Hartman、Colin Perkins、Dan Romascanu、Dan Wing和Qin Wu为本文件的早期草稿提供了宝贵的反馈。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003.
[RFC3550]Schulzrinne，H.，Casner，S.，Frederick，R.，和V.Jacobson，“RTP：实时应用的传输协议”，STD 64，RFC 35502003年7月。
[RFC3611] Friedman, T., Caceres, R., and A. Clark, "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, November 2003.
[RFC3611]Friedman，T.，Caceres，R.，和A.Clark，“RTP控制协议扩展报告（RTCP XR）”，RFC 36112003年11月。
[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.
[RFC4585]Ott，J.，Wenger，S.，Sato，N.，Burmeister，C.，和J.Rey，“基于实时传输控制协议（RTCP）的反馈（RTP/AVPF）的扩展RTP配置文件”，RFC 45852006年7月。
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, July 2006.
[RFC4566]Handley，M.，Jacobson，V.，和C.Perkins，“SDP：会话描述协议”，RFC4566，2006年7月。
[RFC7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count Metric Reporting", RFC 7002, September 2013.
[RFC7002]Clark，A.，Zorn，G.，和Q.Wu，“用于丢弃计数度量报告的RTP控制协议（RTCP）扩展报告（XR）块”，RFC 7002，2013年9月。
[RFC7003] Clark, A., Huang, R., and Q. Wu, "RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap Discard Metric Reporting", RFC 7003, September 2013.
[RFC7003]Clark，A.，Huang，R.，和Q.Wu，“用于突发/间隙丢弃度量报告的RTP控制协议（RTCP）扩展报告（XR）块”，RFC 7003，2013年9月。
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation Applicability Statement", RFC 5481, March 2009.
[RFC5481]Morton，A.和B.Claise，“数据包延迟变化适用性声明”，RFC 54812009年3月。
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004.
[RFC3711]Baugher，M.，McGrew，D.，Naslund，M.，Carrara，E.，和K.Norrman，“安全实时传输协议（SRTP）”，RFC 37112004年3月。
[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.
[RFC5124]Ott，J.和E.Carrara，“基于实时传输控制协议（RTCP）的反馈扩展安全RTP配置文件（RTP/SAVPF）”，RFC 51242008年2月。
[NO-SRTP] Perkins, C. and M. Westerlund, "Securing the RTP Protocol Framework: Why RTP Does Not Mandate a Single Media Security Solution", Work in Progress, October 2013.
[NO-SRTP]Perkins，C.和M.Westerlund，“保护RTP协议框架：为什么RTP不要求单一媒体安全解决方案”，正在进行的工作，2013年10月。
[SRTP-OPTIONS] Westerlund, M. and C. Perkins, "Options for Securing RTP Sessions", Work in Progress, November 2013.
[SRTP-OPTIONS]Westerlund，M.和C.Perkins，“确保RTP会议安全的选项”，正在进行的工作，2013年11月。
[DISCARD-METRIC] Singh, V., Ed., Ott, J., and I. Curcio, "RTP Control Protocol (RTCP) Extended Report (XR) for Bytes Discarded Metric", Work in Progress, November 2013.
[DISCARD-METRIC]Singh，V.，Ed.，Ott，J.，和I.Curcio，“RTP控制协议（RTCP）扩展报告（XR）字节丢弃度量”，正在进行的工作，2013年11月。
a. RLE of Discarded RTP Packets Metric
a. 丢弃RTP包的RLE度量
* Metric Name: RLE - Run-length encoding of Discarded RTP Packets Metric.
* 度量名称：RLE-丢弃RTP数据包的运行长度编码度量。
* Metric Description: Instances of RTP packets discarded over the period covered by this report.
* 指标说明：在本报告涵盖的期间内丢弃的RTP数据包的实例。
* Method of Measurement or Calculation: See Section 3 for the definition of Discard RLE, and Section 4.1 of RFC 3611 for RLE.
* 测量或计算方法：报废RLE的定义见第3节，RLE见RFC 3611第4.1节。
* Units of Measurement: Every RTP packet in the interval is reported as discarded or not. See Section 3 for the definition.
* 测量单位：间隔内的每个RTP数据包都报告为已丢弃或未丢弃。定义见第3节。
* Measurement Point(s) with Potential Measurement Domain: The measurement of these metrics is made at the receiving end of the RTP stream.
* 具有潜在测量域的测量点：这些度量的测量在RTP流的接收端进行。
* Measurement Timing: Each RTP packet between a beginning sequence number (begin_seq) and ending sequence number (end_seq) is reported as discarded or not. See Section 3 for the definition of Discard RLE.
* 测量定时：开始序列号（begin_seq）和结束序列号（end_seq）之间的每个RTP数据包被报告为已丢弃或未丢弃。有关报废RLE的定义，请参见第3节。
* Use and applications: See Section 1, paragraph 1.
* 用途和应用：见第1节第1段。
* Reporting model: See RFC 3611.
* 报告模式：见RFC 3611。
Authors' Addresses
作者地址
Joerg Ott Aalto University School of Electrical Engineering Otakaari 5 A Espoo, FIN 02150 Finland
芬兰芬兰埃斯波奥塔卡里5 A埃斯波约尔格奥特阿尔托大学电气工程学院，邮编：02150
EMail: jo@comnet.tkk.fi
EMail: jo@comnet.tkk.fi
Varun Singh (editor) Aalto University School of Electrical Engineering Otakaari 5 A Espoo, FIN 02150 Finland
Varun Singh（编辑）芬兰芬兰阿尔托大学电气工程学院Otakaari 5 A Espoo 02150
EMail: varun@comnet.tkk.fi
URI: http://www.netlab.tkk.fi/~varun/
EMail: varun@comnet.tkk.fi
URI: http://www.netlab.tkk.fi/~varun/
Igor D.D. Curcio Nokia Research Center P.O. Box 1000 (Visiokatu 3) Tampere, FIN 33721 Finland
芬兰芬兰芬兰坦佩雷Igor D.D.Curcio诺基亚研究中心邮政信箱1000（Visiokatu 3）33721
EMail: igor.curcio@nokia.com
EMail: igor.curcio@nokia.com