Internet Engineering Task Force (IETF) V. Singh
Request for Comments: 8015 callstats.io
Category: Standards Track C. Perkins
ISSN: 2070-1721 University of Glasgow
A. Clark
Telchemy
R. Huang
Huawei
November 2016
Internet Engineering Task Force (IETF) V. Singh
Request for Comments: 8015 callstats.io
Category: Standards Track C. Perkins
ISSN: 2070-1721 University of Glasgow
A. Clark
Telchemy
R. Huang
Huawei
November 2016
RTP Control Protocol (RTCP) Extended Report (XR) Block for Independent Reporting of Burst/Gap Discard Metrics
RTP控制协议（RTCP）扩展报告（XR）块，用于独立报告突发/间隙丢弃度量
Abstract
摘要
This document defines an RTP Control Protocol (RTCP) Extended Report (XR) block that allows the reporting of burst/gap discard metrics independently of the burst/gap loss metrics for use in a range of RTP applications.
本文档定义了一个RTP控制协议（RTCP）扩展报告（XR）块，该块允许在一系列RTP应用程序中独立于突发/间隙丢失度量报告突发/间隙丢弃度量。
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 7841.
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 7841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/rfc8015.
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/rfc8015.
Copyright Notice
版权公告
Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2016 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
1.1. Independent Burst/Gap Discard Metrics Block . . . . . . . 3
1.2. RTCP and RTCP Extended Reports . . . . . . . . . . . . . 4
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Independent Burst/Gap Discard Metrics Block . . . . . . . . . 5
3.1. Report Block Structure . . . . . . . . . . . . . . . . . 6
3.2. Definition of Fields in the Independent Burst/Gap Discard
Metrics Block . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Derived Metrics Based on the Reported Metrics . . . . . . 8
4. Considerations for Voice-over-IP Applications . . . . . . . . 9
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. SDP rtcp-xr Attribute Extension . . . . . . . . . . . . . 9
5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6.1. New RTCP XR Block Type Value . . . . . . . . . . . . . . 10
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10
6.3. Contact Information for Registrations . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Metrics Represented Using the Template from RFC 6390 13
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 14
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Independent Burst/Gap Discard Metrics Block . . . . . . . 3
1.2. RTCP and RTCP Extended Reports . . . . . . . . . . . . . 4
1.3. Performance Metrics Framework . . . . . . . . . . . . . . 4
1.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Independent Burst/Gap Discard Metrics Block . . . . . . . . . 5
3.1. Report Block Structure . . . . . . . . . . . . . . . . . 6
3.2. Definition of Fields in the Independent Burst/Gap Discard
Metrics Block . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Derived Metrics Based on the Reported Metrics . . . . . . 8
4. Considerations for Voice-over-IP Applications . . . . . . . . 9
5. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. SDP rtcp-xr Attribute Extension . . . . . . . . . . . . . 9
5.2. Offer/Answer Usage . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6.1. New RTCP XR Block Type Value . . . . . . . . . . . . . . 10
6.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . 10
6.3. Contact Information for Registrations . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Metrics Represented Using the Template from RFC 6390 13
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 14
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
This document defines a new block type that extends the metrics defined in [RFC7003]. The new block type reports the proportion of packets discarded in a burst by the de-jitter buffer at the receiver. The number of packets discarded depends on the de-jitter buffer algorithm implemented by the endpoint.
本文档定义了扩展[RFC7003]中定义的度量的新块类型。新的块类型报告接收器处的去抖动缓冲器在突发中丢弃的数据包的比例。丢弃的数据包数量取决于端点实现的去抖动缓冲算法。
The new report block defined in this document is different from the one defined in [RFC7003]. The metrics in [RFC7003] depend on the metrics in the burst/gap loss metric defined in [RFC6958]. Consequently, an endpoint that sends a Burst/Gap Discard Metrics Block [RFC7003] also needs to send a Burst/Gap Loss Metrics Block [RFC6958]. The combined usage is useful when an endpoint observes correlated packet losses and discard. However, when the burst of packet losses and discards do not occur simultaneously, the application could prefer to send a concise report block that just reports the burst/gap of discarded packets. The report block in this document provides the complete information and does not require additional report blocks. That is, this block reports the total number of packets discarded, the total burst duration, and the total number of bursts. All of these metrics are missing in [RFC7003].
本文档中定义的新报告块与[RFC7003]中定义的报告块不同。[RFC7003]中的指标取决于[RFC6958]中定义的突发/间隙损失指标中的指标。因此，发送突发/间隔丢弃度量块[RFC7003]的端点还需要发送突发/间隔丢失度量块[RFC6958]。当端点观察到相关的数据包丢失和丢弃时，组合使用非常有用。然而，当分组丢失和丢弃的突发不同时发生时，应用程序可能更倾向于发送一个简明的报告块，该报告块只报告丢弃分组的突发/间隔。本文档中的报告块提供了完整的信息，不需要额外的报告块。也就是说，该块报告丢弃的数据包总数、总突发持续时间和突发总数。[RFC7003]中缺少所有这些指标。
This block provides information on transient network issues. Burst/ gap metrics are typically used in cumulative reports; however, they can also be used in interval reports (see the Interval Metric flag in Section 3.2). The variation in the number of packet discards in a burst affects the user experience. Based on the metrics reported in the block, the sending endpoint can change the packetization interval, vary the bitrate, etc. The report can additionally be used for diagnostics [RFC6792]. The metric belongs to the class of transport-related end-system metrics defined in [RFC6792].
此块提供有关瞬时网络问题的信息。突发/间隙指标通常用于累积报告中；但是，它们也可用于间隔报告（参见第3.2节中的间隔度量标志）。突发中数据包丢弃数量的变化会影响用户体验。根据块中报告的度量，发送端点可以更改分组间隔、改变比特率等。该报告还可用于诊断[RFC6792]。该指标属于[RFC6792]中定义的与传输相关的终端系统指标类别。
The definitions of "burst", "gap", "loss", and "discard" are consistent with the definitions in [RFC3611]. To accommodate a range of de-jitter buffer algorithms and packet discard logic that can be used by implementers, the method used to distinguish between bursts and gaps uses an equivalent method to that defined in Section 4.7.2 of [RFC3611]. Note that reporting the specific de-jitter buffer algorithm and/or the packet discard logic is out of the scope of this document.
“突发”、“间隙”、“丢失”和“丢弃”的定义与[RFC3611]中的定义一致。为了适应实施者可以使用的一系列去抖动缓冲算法和数据包丢弃逻辑，用于区分突发和间隙的方法使用了[RFC3611]第4.7.2节中定义的等效方法。请注意，报告特定的去抖动缓冲算法和/或数据包丢弃逻辑不在本文档范围内。
The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] defined an extensible structure for reporting using an RTCP Extended Report (XR). This document defines a new Extended Report block for use with [RFC3550] and [RFC3611].
[RFC3550]中定义了使用RTCP进行报告。[RFC3611]定义了使用RTCP扩展报告（XR）进行报告的可扩展结构。本文档定义了一个新的扩展报告块，用于[RFC3550]和[RFC3611]。
The Performance Metrics Framework [RFC6390] provides guidance on the definition and specification of performance metrics. The RTP Monitoring Framework [RFC6792] provides guidelines for reporting the block format using RTCP XR. The metrics block described in this document is in accordance with the guidelines in [RFC6390] and [RFC6792].
性能指标框架[RFC6390]提供了有关性能指标定义和规范的指导。RTP监控框架[RFC6792]提供了使用RTCP XR报告块格式的指南。本文件中描述的度量块符合[RFC6390]和[RFC6792]中的指南。
These metrics are applicable to a range of RTP applications that contain de-jitter buffers at the receiver to smooth variation in packet-arrival time and don't use stream repair means, e.g., Forward Error Correction (FEC) [FLEX_FEC] and/or retransmission [RFC4588].
这些量度适用于一系列RTP应用，这些RTP应用在接收器处包含去抖动缓冲器，以平滑分组到达时间的变化，并且不使用流修复手段，例如前向纠错（FEC）[FLEX_-FEC]和/或重传[RFC4588]。
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 RFC 2119 [RFC2119].
本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。
In addition, the following terms are defined:
此外，定义了以下术语：
Received, Lost, and Discarded
接收、丢失和丢弃
A packet is regarded as "lost" if it fails to arrive within an implementation-specific time window. A packet that arrives within this time window but is too early to be played out, too late to be played out, or thrown away before playout due to packet duplication or redundancy is be recorded as "discarded". A packet SHALL NOT be regarded as "discarded" if it arrives within this time window but is dropped during decoding by some higher-layer decoder, e.g., due to a decoding error. Each packet is classified as one of "received" (or "OK"), "discarded", or "lost". The metric "cumulative number of packets lost" defined in [RFC3550] reports a count of packets lost from the media stream (single synchronization source (SSRC) within a single RTP session). Similarly, the metric "number of packets discarded" defined in [RFC7002] reports a count of packets discarded from the media stream (single SSRC within a single RTP session) arriving at the
如果数据包未能在特定于实现的时间窗口内到达，则视为“丢失”。在该时间窗口内到达但由于数据包重复或冗余而过早播放、太晚播放或在播放前丢弃的数据包将被记录为“丢弃”。如果数据包在此时间窗口内到达，但在某个更高层解码器解码期间（例如，由于解码错误）被丢弃，则该数据包不应被视为“丢弃”。每个数据包被分类为“接收”（或“确定”）、“丢弃”或“丢失”中的一个。[RFC3550]中定义的度量“累计丢失的数据包数”报告从媒体流（单个RTP会话中的单个同步源（SSRC））丢失的数据包计数。类似地，[RFC7002]中定义的度量“丢弃的数据包数量”报告从媒体流（单个RTP会话中的单个SSRC）丢弃的数据包的计数，该媒体流到达终端
receiver. Another metric, defined in [RFC5725], is available to report on packets that are not recovered by any repair techniques that are in use. Note that the term "discard" defined here builds on the "discard" definition in [RFC3611] but extends the concept to take into account packet duplication and reports different types of discard counts [RFC7002].
接受者[RFC5725]中定义的另一个指标可用于报告使用的任何修复技术都无法恢复的数据包。注意，此处定义的术语“丢弃”基于[RFC3611]中的“丢弃”定义，但扩展了该概念，以考虑数据包重复并报告不同类型的丢弃计数[RFC7002]。
Bursts and Gaps
爆发和缺口
The terms "burst" and "gap" are used in a manner consistent with that of RTCP XR [RFC3611]. RTCP XR views an RTP stream as being divided into bursts, which are periods during which the discard rate is high enough to cause noticeable quality degradation (generally a discard rate over 5 percent), and gaps, which are periods during which discarded packets are infrequent, and hence quality is generally acceptable.
术语“突发”和“间隙”的使用方式与RTCP XR[RFC3611]一致。RTCP XR将RTP流视为被划分为突发，突发是指丢弃率高到足以导致明显质量下降（通常丢弃率超过5%）的时段，间隙是指丢弃的数据包不频繁的时段，因此质量通常是可接受的。
Metrics in this block report on burst/gap discard in the stream arriving at the RTP system. Measurements of these metrics are made at the receiving end of the RTP stream. Instances of this metrics block use the synchronization source (SSRC) to refer to the separate auxiliary Measurement Information Block [RFC6776], which describes measurement periods in use (see [RFC6776], Section 4.2).
此块中的度量报告到达RTP系统的流中的突发/间隙丢弃。在RTP流的接收端对这些度量进行测量。此度量块的实例使用同步源（SSRC）引用单独的辅助度量信息块[RFC6776]，该信息块描述了使用中的度量周期（请参见[RFC6776]，第4.2节）。
This metrics block relies on the measurement period in the Measurement Information Block indicating the span of the report. Senders MUST send this block in the same compound RTCP packet as the Measurement Information Block. Receivers MUST verify that the measurement period is received in the same compound RTCP packet as this metrics block. If not, this metrics block MUST be discarded.
此度量块依赖于度量信息块中指示报告范围的度量周期。发送方必须在与测量信息块相同的复合RTCP数据包中发送此数据块。接收器必须验证测量周期是否在与此度量块相同的复合RTCP数据包中接收。如果不是，则必须放弃此度量块。
The structure of the Independent Burst/Gap Discard Metrics Block is as follows.
独立突发/间隙丢弃度量块的结构如下所示。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=35 | I | resv | Block Length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold | Sum of Burst Durations (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packets Discarded in Bursts | Number of |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bursts | Total Packets Expected in Bursts |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discard Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=35 | I | resv | Block Length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold | Sum of Burst Durations (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packets Discarded in Bursts | Number of |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bursts | Total Packets Expected in Bursts |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discard Count |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Report Block Structure
图1：报告块结构
3.2. Definition of Fields in the Independent Burst/Gap Discard Metrics Block
3.2. 独立突发/间隙丢弃度量块中字段的定义
Block Type (BT): 8 bits
块类型（BT）：8位
An Independent Burst/Gap Discard Metrics Block is identified by the constant 35.
独立的突发/间隙丢弃度量块由常数35标识。
Interval Metric flag (I): 2 bits
间隔度量标志（I）：2位
This field is used to indicate whether the burst/gap discard metrics are Sampled, Interval, or Cumulative metrics [RFC6792]:
此字段用于指示突发/间隔丢弃度量是采样、间隔还是累积度量[RFC6792]：
I=10: Interval Duration - the reported value applies to the most recent measurement interval duration between successive metrics reports.
I=10：间隔持续时间-报告值适用于连续度量报告之间的最新度量间隔持续时间。
I=11: Cumulative Duration - the reported value applies to the accumulation period characteristic of cumulative measurements.
I=11：累积持续时间-报告值适用于累积测量的累积周期特征。
In this document, burst/gap discard metrics can only be measured over definite intervals and cannot be sampled. Also, the value I=00 is reserved for future use. Senders MUST NOT use the values I=00 or I=01. If a block is received with I=00 or I=01, the receiver MUST discard the block.
在本文档中，突发/间隙丢弃度量只能在确定的时间间隔内进行测量，不能进行采样。此外，值I=00保留供将来使用。发件人不得使用I=00或I=01的值。如果接收到I=00或I=01的块，接收器必须丢弃该块。
Reserved (resv): 6 bits
保留（resv）：6位
These bits are reserved. They MUST be set to zero by senders and ignored by receivers (see [RFC6709], Section 4.2).
这些位是保留的。发送方必须将其设置为零，接收方必须忽略（见[RFC6709]，第4.2节）。
Block Length: 16 bits
块长度：16位
The length of this report block in 32-bit words, minus one. For the Independent Burst/Gap Discard Metrics Block, the block length is equal to 5. The block MUST be discarded if the block length is set to a different value.
此报表块的长度（32位字）减去1。对于独立突发/间隙丢弃度量块，块长度等于5。如果块长度设置为不同的值，则必须丢弃该块。
SSRC of Source: 32 bits
源的SSRC：32位
As defined in Section 4 of [RFC3611].
如[RFC3611]第4节所定义。
Threshold: 8 bits
阈值：8位
The Threshold is equivalent to Gmin in [RFC3611], i.e., the number of successive packets that have to be received prior to, and following, a discarded packet in order for that discarded packet to be regarded as part of a gap. Note that the Threshold is set in accordance with the Gmin calculation defined in Section 4.7.2 of [RFC3611].
阈值相当于[RFC3611]中的Gmin，即在丢弃的分组之前和之后必须接收的连续分组的数量，以便将该丢弃的分组视为间隙的一部分。注意，阈值是根据[RFC3611]第4.7.2节中定义的Gmin计算设置的。
Sum of Burst Durations (ms): 24 bits
突发持续时间之和（毫秒）：24位
The total duration of bursts of discarded packets in the period of the report (Interval or Cumulative).
报告期间丢弃数据包突发的总持续时间（间隔或累积）。
The measured value is an unsigned value. If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFFFF MUST be reported.
测量值为无符号值。如果测量值超过0xFFFFFD，则必须报告值0xFFFFFE以指示超量程测量。如果测量不可用，则必须报告值0xFFFFFF。
Packets Discarded in Bursts: 24 bits
突发丢弃的数据包：24位
The total number of packets discarded during discard bursts, as defined in Section 3.2 of [RFC7002].
丢弃突发期间丢弃的数据包总数，如[RFC7002]第3.2节所定义。
Number of Bursts: 16 bits
突发数：16位
The number of discard bursts in the period of the report (Interval or Cumulative).
报告期间的丢弃突发数（间隔或累积）。
The measured value is an unsigned value. If the measured value exceeds 0xFFFD, the value 0xFFFE MUST be reported to indicate an over-range measurement. If the measurement is unavailable, the value 0xFFFF MUST be reported.
测量值为无符号值。如果测量值超过0xFFFD，则必须报告值0xFFFE以指示超量程测量。如果测量不可用，则必须报告值0xFFFF。
Total Packets Expected in Bursts: 24 bits
突发中预期的数据包总数：24位
The total number of packets expected during the discard bursts (that is, the sum of received packets and lost packets). The metric is defined in [RFC7003].
丢弃突发期间预期的数据包总数（即接收到的数据包和丢失的数据包之和）。该指标在[RFC7003]中定义。
Discard Count: 32 bits
丢弃计数：32位
Number of packets discarded over the period (Interval or Cumulative) covered by this report, as defined in Section 3.2 of [RFC7002].
根据[RFC7002]第3.2节的定义，在本报告涵盖的时间段（间隔或累积）内丢弃的数据包数。
The metrics described here are intended to be used in conjunction with information from the Measurement Information Block [RFC6776].
此处描述的指标旨在与测量信息块[RFC6776]中的信息结合使用。
These metrics provide the following information relevant to statistical parameters (depending on cumulative of interval measures), for example:
这些指标提供了与统计参数相关的以下信息（取决于累积的间隔度量），例如：
o The average discarded burst size, which can be calculated by dividing the metric "Packets Discarded in Bursts" by the "Number of Bursts".
o 平均丢弃的突发大小，可通过将度量“突发中丢弃的数据包”除以“突发数”来计算。
o The average burst duration, which can be calculated by dividing the metric "Sum of Burst Durations (ms)" by the "Number of Bursts".
o 平均突发持续时间，可通过将度量“突发持续时间总和（ms）”除以“突发次数”来计算。
This metrics block is applicable to a broad range of RTP applications. Where the metric is used with a Voice-over-IP (VoIP) application and the stream repair means is not available, the following considerations apply.
此度量块适用于广泛的RTP应用程序。如果该度量用于IP语音（VoIP）应用程序，且流修复手段不可用，则以下注意事项适用。
RTCP XR views a call as being divided into bursts, which are periods during which the discard rate is high enough to cause noticeable call quality degradation (generally a discard rate over 5 percent) and gaps, which are periods during which discarded packets are infrequent, and hence call quality is generally acceptable.
RTCP XR将呼叫视为分为突发，突发是指丢弃率高到足以导致明显呼叫质量下降（通常丢弃率超过5%）的时段和间隔，间隔是指丢弃的数据包不频繁的时段，因此呼叫质量通常是可接受的。
If voice activity detection is used, the burst/gap duration is determined as if silence packets had been sent, i.e., a period of silence in excess of Gmin packets will terminate a burst condition.
如果使用语音活动检测，则突发/间隔持续时间的确定与静默分组已发送的情况相同，即，超过Gmin分组的静默时间将终止突发条件。
The RECOMMENDED value for the threshold Gmin in [RFC3611] results in a burst being a period of time during which the call quality is degraded to a similar extent to a typical pulse code modulation (PCM) severely errored second.
[RFC3611]中阈值Gmin的建议值会导致突发，这是一段时间，在此期间，呼叫质量下降到与典型脉冲编码调制（PCM）严重错误秒相似的程度。
[RFC3611] defines the use of SDP (Session Description Protocol) [RFC4566] for signaling the use of XR blocks. XR blocks can be used without prior signaling.
[RFC3611]定义了SDP（会话描述协议）[RFC4566]的使用，用于发送使用XR块的信号。XR块可以在没有事先信令的情况下使用。
This section augments the SDP [RFC4566] attribute "rtcp-xr" defined in [RFC3611] by providing an additional value of "xr-format" to signal the use of the report block defined in this document. The ABNF [RFC5234] syntax is as follows.
本节增加了[RFC3611]中定义的SDP[RFC4566]属性“rtcp xr”，提供了“xr format”的附加值，以表示使用了本文档中定义的报告块。ABNF[RFC5234]语法如下所示。
xr-format =/ xr-ind-bgd-block
xr format=/xr ind bgd块
xr-ind-bgd-block = "ind-burst-gap-discard"
xr ind bgd block=“ind突发间隔丢弃”
When SDP is used in Offer/Answer context, the SDP Offer/Answer usage defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters applies. For detailed usage in Offer/Answer for unilateral parameters, refer to Section 5.2 of [RFC3611].
在提供/应答上下文中使用SDP时，[RFC3611]中为单边“rtcp xr”属性参数定义的SDP提供/应答用法适用。有关单边参数在报价/应答中的详细用法，请参阅[RFC3611]第5.2节。
New block types for RTCP XR are subject to IANA registration. For general guidelines on IANA considerations for RTCP XR, refer to [RFC3611].
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[RFC3611]。
This document assigns the block type value 35 in the IANA "RTP Control Protocol Extended Reports (RTCP XR) Block Type Registry" to the "Independent Burst/Gap Discard Metrics Block".
本文档将IANA“RTP控制协议扩展报告（RTCP XR）块类型注册表”中的块类型值35分配给“独立突发/间隙丢弃度量块”。
This document also registers a new parameter "ind-burst-gap-discard" in the "RTP Control Protocol Extended Reports (RTCP XR) Session Description Protocol (SDP) Parameters Registry".
本文档还在“RTP控制协议扩展报告（RTCP XR）会话描述协议（SDP）参数注册表”中注册一个新参数“ind突发间隔丢弃”。
The contact information for the registrations is:
注册的联系信息为：
ART Area Directors <art-ads@ietf.org>
ART Area Directors <art-ads@ietf.org>
This block does not provide per-packet statistics, so the risk to confidentiality documented in Section 7, paragraph 3 of [RFC3611] does not apply. However, the gap indicated within this block could be used to detect the timing of other events on the path between the sender and receiver. For example, a competing multimedia stream might cause a discard burst for the duration of the stream, allowing the receiver of this block to know when the competing stream was active. This risk is not a significant threat since the only information leaked is the timing of the discard, not the cause.
该块不提供每包统计数据，因此[RFC3611]第7节第3段中记录的保密风险不适用。然而，该块中指示的间隙可用于检测发送方和接收方之间路径上其他事件的定时。例如，竞争多媒体流可能在流的持续时间内导致丢弃突发，从而允许该块的接收器知道竞争流何时处于活动状态。这种风险不是重大威胁，因为泄漏的唯一信息是丢弃的时间，而不是原因。
Where this is a concern, the implementation SHOULD apply encryption and authentication to this report block. For example, this can be achieved by using the Audio-Visual Profile with Feedback (AVPF) profile together with the Secure RTP profile, as defined in [RFC3711]; an appropriate combination of those two profiles ("SAVPF") is specified in [RFC5124]. Besides this, it is believed that this RTCP XR block introduces no new security considerations beyond those described in [RFC3611].
考虑到这一点，实现应该对此报告块应用加密和身份验证。例如，如[RFC3711]中所定义，这可以通过使用带反馈的视听配置文件（AVPF）配置文件以及安全RTP配置文件来实现；[RFC5124]中规定了这两个配置文件的适当组合（“SAVPF”）。除此之外，人们认为，除了[RFC3611]中所述的安全注意事项外，该RTCP XR块没有引入任何新的安全注意事项。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<http://www.rfc-editor.org/info/rfc2119>.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July 2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC3550]Schulzrinne，H.，Casner，S.，Frederick，R.，和V.Jacobson，“RTP：实时应用的传输协议”，STD 64，RFC 3550，DOI 10.17487/RFC3550，2003年7月<http://www.rfc-editor.org/info/rfc3550>.
[RFC3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed., "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, DOI 10.17487/RFC3611, November 2003, <http://www.rfc-editor.org/info/rfc3611>.
[RFC3611]Friedman，T.，Ed.，Caceres，R.，Ed.，和A.Clark，Ed.，“RTP控制协议扩展报告（RTCP XR）”，RFC 3611，DOI 10.17487/RFC36112003年11月<http://www.rfc-editor.org/info/rfc3611>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, DOI 10.17487/RFC3711, March 2004, <http://www.rfc-editor.org/info/rfc3711>.
[RFC3711]Baugher，M.，McGrew，D.，Naslund，M.，Carrara，E.，和K.Norrman，“安全实时传输协议（SRTP）”，RFC 3711，DOI 10.17487/RFC3711，2004年3月<http://www.rfc-editor.org/info/rfc3711>.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, DOI 10.17487/RFC4566, July 2006, <http://www.rfc-editor.org/info/rfc4566>.
[RFC4566]Handley，M.，Jacobson，V.，和C.Perkins，“SDP：会话描述协议”，RFC 4566，DOI 10.17487/RFC4566，2006年7月<http://www.rfc-editor.org/info/rfc4566>.
[RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC5124, February 2008, <http://www.rfc-editor.org/info/rfc5124>.
[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 5124DOI 10.17487/RFC5124，2008年2月<http://www.rfc-editor.org/info/rfc5124>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, DOI 10.17487/RFC5234, January 2008, <http://www.rfc-editor.org/info/rfc5234>.
[RFC5234]Crocker，D.，Ed.和P.Overell，“语法规范的扩充BNF:ABNF”，STD 68，RFC 5234，DOI 10.17487/RFC5234，2008年1月<http://www.rfc-editor.org/info/rfc5234>.
[RFC5725] Begen, A., Hsu, D., and M. Lague, "Post-Repair Loss RLE Report Block Type for RTP Control Protocol (RTCP) Extended Reports (XRs)", RFC 5725, DOI 10.17487/RFC5725, February 2010, <http://www.rfc-editor.org/info/rfc5725>.
[RFC5725]Begen，A.，Hsu，D.，和M.Lague，“RTP控制协议（RTCP）扩展报告（XRs）的修复后损失RLE报告块类型”，RFC 5725，DOI 10.17487/RFC5725，2010年2月<http://www.rfc-editor.org/info/rfc5725>.
[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, DOI 10.17487/RFC6776, October 2012, <http://www.rfc-editor.org/info/rfc6776>.
[RFC6776]Clark，A.和Q.Wu，“使用源描述（SDES）项和RTCP扩展报告（XR）块的测量标识和信息报告”，RFC 6776，DOI 10.17487/RFC6776，2012年10月<http://www.rfc-editor.org/info/rfc6776>.
[RFC7003] Clark, A., Huang, R., and Q. Wu, Ed., "RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap Discard Metric Reporting", RFC 7003, DOI 10.17487/RFC7003, September 2013, <http://www.rfc-editor.org/info/rfc7003>.
[RFC7003]Clark，A.，Huang，R.，和Q.Wu，Ed.，“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，DOI 10.17487/RFC7003，2013年9月<http://www.rfc-editor.org/info/rfc7003>.
[FLEX_FEC] Singh, V., Begen, A., Zanaty, M., and G. Mandyam, "RTP Payload Format for Flexible Forward Error Correction (FEC)", Work in Progress, draft-ietf-payload-flexible-fec-scheme-03, October 2016.
[FLEX_FEC]Singh，V.，Begen，A.，Zanaty，M.，和G.Mandyam，“灵活前向纠错（FEC）的RTP有效载荷格式”，正在进行的工作，草案-ietf-Payload-Flexible-FEC-scheme-032016年10月。
[RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R. Hakenberg, "RTP Retransmission Payload Format", RFC 4588, DOI 10.17487/RFC4588, July 2006, <http://www.rfc-editor.org/info/rfc4588>.
[RFC4588]Rey，J.，Leon，D.，Miyazaki，A.，Varsa，V.，和R.Hakenberg，“RTP重传有效载荷格式”，RFC 4588，DOI 10.17487/RFC4588，2006年7月<http://www.rfc-editor.org/info/rfc4588>.
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New Performance Metric Development", BCP 170, RFC 6390, DOI 10.17487/RFC6390, October 2011, <http://www.rfc-editor.org/info/rfc6390>.
[RFC6390]Clark，A.和B.Claise，“考虑新绩效指标开发的指南”，BCP 170，RFC 6390，DOI 10.17487/RFC6390，2011年10月<http://www.rfc-editor.org/info/rfc6390>.
[RFC6709] Carpenter, B., Aboba, B., Ed., and S. Cheshire, "Design Considerations for Protocol Extensions", RFC 6709, DOI 10.17487/RFC6709, September 2012, <http://www.rfc-editor.org/info/rfc6709>.
[RFC6709]Carpenter，B.，Aboba，B.，Ed.，和S.Cheshire，“协议扩展的设计考虑”，RFC 6709，DOI 10.17487/RFC6709，2012年9月<http://www.rfc-editor.org/info/rfc6709>.
[RFC6792] Wu, Q., Ed., Hunt, G., and P. Arden, "Guidelines for Use of the RTP Monitoring Framework", RFC 6792, DOI 10.17487/RFC6792, November 2012, <http://www.rfc-editor.org/info/rfc6792>.
[RFC6792]Wu，Q.，Ed.，Hunt，G.，和P.Arden，“RTP监测框架的使用指南”，RFC 6792，DOI 10.17487/RFC6792，2012年11月<http://www.rfc-editor.org/info/rfc6792>.
[RFC6958] Clark, A., Zhang, S., Zhao, J., and Q. Wu, Ed., "RTP Control Protocol (RTCP) Extended Report (XR) Block for Burst/Gap Loss Metric Reporting", RFC 6958, DOI 10.17487/RFC6958, May 2013, <http://www.rfc-editor.org/info/rfc6958>.
[RFC6958]Clark，A.，Zhang，S.，Zhao，J.，和Q.Wu，Ed.，“用于突发/间隙损失度量报告的RTP控制协议（RTCP）扩展报告（XR）块”，RFC 6958，DOI 10.17487/RFC6958，2013年5月<http://www.rfc-editor.org/info/rfc6958>.
[RFC7002] Clark, A., Zorn, G., and Q. Wu, "RTP Control Protocol (RTCP) Extended Report (XR) Block for Discard Count Metric Reporting", RFC 7002, DOI 10.17487/RFC7002, September 2013, <http://www.rfc-editor.org/info/rfc7002>.
[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，DOI 10.17487/RFC7002，2013年9月<http://www.rfc-editor.org/info/rfc7002>.
a. Threshold Metric
a. 阈值度量
* Defined in item a of Appendix A of [RFC7003].
* 定义见[RFC7003]附录a第a项。
b. Sum of Burst Durations (ms)
b. 突发持续时间之和（ms）
* Metric Name: Sum of Burst Durations with Discarded RTP Packets.
* 度量名称：丢弃RTP数据包的突发持续时间之和。
* Metric Description: The total duration of bursts of discarded RTP packets in the period of the report.
* 度量说明：报告期间丢弃的RTP数据包突发的总持续时间。
* Method of Measurement or Calculation: See Section 3.2, Sum of Burst Durations definition.
* 测量或计算方法：见第3.2节，爆破持续时间总和定义。
* Units of Measurement: See Section 3.2, Sum of Burst Durations definition.
* 测量单位：见第3.2节，脉冲持续时间总和定义。
* Measurement Point(s) with Potential Measurement Domain: See Section 3, first paragraph.
* 具有潜在测量域的测量点：见第3节第一段。
* Measurement Timing: See Section 3, second paragraph for measurement timing and Section 3.2 for Interval Metric flag.
* 测量定时：测量定时见第3节第二段，间隔公制标志见第3.2节。
* Use and Applications: See Section 1.4.
* 用途和应用：见第1.4节。
* Reporting Model: See [RFC3611].
* 报告模型：请参见[RFC3611]。
c. Packets Discarded in Bursts Metric
c. 在突发度量中丢弃的数据包
* Defined in item b of Appendix A of [RFC7003].
* 定义见[RFC7003]附录A第b项。
d. Number of Bursts
d. 爆发次数
* Metric Name: Number of discard bursts in RTP.
* 度量名称：RTP中的丢弃突发数。
* Metric Description: The total number of bursts with discarded RTP packets in the period of the report.
* 度量说明：报告期间丢弃RTP数据包的突发总数。
* Method of Measurement or Calculation: See Section 3.2, Number of Bursts definition.
* 测量或计算方法：见第3.2节，爆炸次数定义。
* Units of Measurement: See Section 3.2 for the Number of Bursts definition.
* 测量单位：有关突发次数的定义，请参见第3.2节。
* Measurement Point(s) with Potential Measurement Domain: See Section 3, first paragraph.
* 具有潜在测量域的测量点：见第3节第一段。
* Measurement Timing: See Section 3, second paragraph for measurement timing and Section 3.2 for Interval Metric flag.
* 测量定时：测量定时见第3节第二段，间隔公制标志见第3.2节。
* Use and Applications: See Section 1.4.
* 用途和应用：见第1.4节。
* Reporting Model: See [RFC3611].
* 报告模型：请参见[RFC3611]。
e. Total Packets Expected in Bursts Metric
e. 突发度量中预期的数据包总数
* Defined in item c of Appendix A of [RFC7003].
* 定义见[RFC7003]附录A第c项。
f. Discard Count
f. 丢弃计数
* Defined in Appendix A of [RFC7002].
* 在[RFC7002]的附录A中定义。
Acknowledgments
致谢
The authors would like to thank Ben Campbell, Stephen Farrell, Paul Kyzivat, Shucheng LIU, Jan Novak, and Dan Romascanu for providing valuable feedback on this document.
作者要感谢Ben Campbell、Stephen Farrell、Paul Kyzivat、Shucheng LIU、Jan Novak和Dan Romascanu为本文件提供了宝贵的反馈。
Contributors
贡献者
Qin Wu, Rachel Huang, and Alan Clark wrote RFC 7003, which this document extends.
秦武、雷切尔·黄和艾伦·克拉克编写了RFC 7003，本文档对其进行了扩展。
Authors' Addresses
作者地址
Varun Singh CALLSTATS I/O Oy Runeberginkatu 4c A 4 Helsinki 00100 Finland
Varun Singh CALLSTATS I/O Oy Runeberginkatu 4c A 4赫尔辛基00100芬兰
Email: varun@callstats.io
URI: https://www.callstats.io/about
Email: varun@callstats.io
URI: https://www.callstats.io/about
Colin Perkins University of Glasgow School of Computing Science Glasgow G12 8QQ United Kingdom
柯林帕金斯格拉斯哥大学计算科学学院格拉斯哥G128QQ英国
Email: csp@csperkins.org
Email: csp@csperkins.org
Alan Clark Telchemy Incorporated 2905 Premiere Parkway, Suite 280 Duluth, GA 30097 United States of America
Alan Clark Telchemy Incorporated 2905 Premiere Parkway，美国佐治亚州德卢斯280号套房，邮编30097
Email: alan.d.clark@telchemy.com
Email: alan.d.clark@telchemy.com
Rachel Huang Huawei Technologies Co., Ltd. 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China
中国江苏省南京市雨花区软件大道101号瑞秋黄华为技术有限公司210012
Email: Rachel@huawei.com
Email: Rachel@huawei.com