Network Working Group H. Uijterwaal
Request for Comments: 5560 RIPE NCC
Category: Standards Track May 2009
Network Working Group H. Uijterwaal
Request for Comments: 5560 RIPE NCC
Category: Standards Track May 2009
A One-Way Packet Duplication Metric
一种单向数据包复制度量
Status of This Memo
关于下段备忘
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document.
本文件受BCP 78和IETF信托在本文件出版之日生效的与IETF文件有关的法律规定的约束(http://trustee.ietf.org/license-info). 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。
Abstract
摘要
When a packet is sent from one host to the other, one normally expects that exactly one copy of the packet that was sent arrives at the destination. It is, however, possible that a packet is either lost or that multiple copies arrive.
当一个数据包从一个主机发送到另一个主机时，通常期望发送的数据包的一个副本正好到达目的地。然而，有可能一个数据包丢失或多个副本到达。
In earlier work, a metric for packet loss was defined. This metric quantifies the case where a packet that is sent does not arrive at its destination within a reasonable time. In this memo, a metric for another case is defined: a packet is sent, but multiple copies arrive. The document also discusses streams and methods to summarize the results of streams.
在早期的工作中，定义了数据包丢失的度量。该度量量化了发送的数据包未在合理时间内到达目的地的情况。在本备忘录中，定义了另一种情况的度量：发送一个数据包，但到达多个副本。本文档还讨论了流和总结流结果的方法。
Table of Contents
目录
1. Introduction ....................................................3
1.1. Requirements Notation ......................................3
1.2. Motivation .................................................4
2. A Singleton Definition for One-Way Packet Arrival Count .........4
2.1. Metric Name ................................................4
2.2. Metrics Parameters .........................................4
2.3. Metric Units ...............................................4
2.4. Definition .................................................4
2.5. Discussion .................................................5
2.6. Methodology ................................................6
2.7. Errors and Uncertainties ...................................6
2.8. Reporting the Metric .......................................6
3. A Singleton Definition for One-Way Packet Duplication ...........6
3.1. Metric Name ................................................6
3.2. Metrics Parameters .........................................7
3.3. Metric Units ...............................................7
3.4. Definition .................................................7
3.5. Discussion .................................................7
4. Definition for Samples for One-Way Packet Duplication ...........7
4.1. Poisson Streams ............................................7
4.1.1. Metric Name .........................................7
4.1.2. Metric Parameters ...................................8
4.1.3. Metric Units ........................................8
4.1.4. Definition ..........................................8
4.1.5. Methodology .........................................8
4.1.6. Errors and Uncertainties ............................8
4.1.7. Reporting the Metric ................................8
4.2. Periodic Streams ...........................................9
4.2.1. Metric Name .........................................9
4.2.2. Metric Parameters ...................................9
4.2.3. Metric Units ........................................9
4.2.4. Definition ..........................................9
4.2.5. Methodology .........................................9
4.2.6. Errors and uncertainties ............................9
4.2.7. Reporting the metric ...............................10
5. Some Statistics Definitions for One-Way Duplication ............10
5.1. Type-P-one-way-packet-duplication-fraction ................10
5.2. Type-P-one-way-replicated-packet-rate .....................10
5.3. Examples ..................................................11
6. Security Considerations ........................................12
7. IANA Considerations ............................................12
8. Acknowledgements ...............................................13
9. References .....................................................13
9.1. Normative References ......................................13
9.2. Informative References ....................................13
1. Introduction ....................................................3
1.1. Requirements Notation ......................................3
1.2. Motivation .................................................4
2. A Singleton Definition for One-Way Packet Arrival Count .........4
2.1. Metric Name ................................................4
2.2. Metrics Parameters .........................................4
2.3. Metric Units ...............................................4
2.4. Definition .................................................4
2.5. Discussion .................................................5
2.6. Methodology ................................................6
2.7. Errors and Uncertainties ...................................6
2.8. Reporting the Metric .......................................6
3. A Singleton Definition for One-Way Packet Duplication ...........6
3.1. Metric Name ................................................6
3.2. Metrics Parameters .........................................7
3.3. Metric Units ...............................................7
3.4. Definition .................................................7
3.5. Discussion .................................................7
4. Definition for Samples for One-Way Packet Duplication ...........7
4.1. Poisson Streams ............................................7
4.1.1. Metric Name .........................................7
4.1.2. Metric Parameters ...................................8
4.1.3. Metric Units ........................................8
4.1.4. Definition ..........................................8
4.1.5. Methodology .........................................8
4.1.6. Errors and Uncertainties ............................8
4.1.7. Reporting the Metric ................................8
4.2. Periodic Streams ...........................................9
4.2.1. Metric Name .........................................9
4.2.2. Metric Parameters ...................................9
4.2.3. Metric Units ........................................9
4.2.4. Definition ..........................................9
4.2.5. Methodology .........................................9
4.2.6. Errors and uncertainties ............................9
4.2.7. Reporting the metric ...............................10
5. Some Statistics Definitions for One-Way Duplication ............10
5.1. Type-P-one-way-packet-duplication-fraction ................10
5.2. Type-P-one-way-replicated-packet-rate .....................10
5.3. Examples ..................................................11
6. Security Considerations ........................................12
7. IANA Considerations ............................................12
8. Acknowledgements ...............................................13
9. References .....................................................13
9.1. Normative References ......................................13
9.2. Informative References ....................................13
This document defines a metric for one-way packet duplication across Internet paths. It builds on the IP Performance Metrics (IPPM) Framework document [RFC2330]; the reader is assumed to be familiar with that document.
本文档定义了跨Internet路径的单向数据包复制的度量。它建立在IP性能指标（IPPM）框架文件[RFC2330]的基础上；假定读者熟悉该文档。
This document follows the same structure as the document for one-way packet loss [RFC2680]; the reader is assumed to be familiar with that document as well.
本文件采用与单向分组丢失[RFC2680]文件相同的结构；假定读者也熟悉该文档。
The structure of this memo is as follows:
本备忘录的结构如下：
o First, a singleton metric, called Type-P-one-way-packet-arrival-count, is introduced to measure the number of arriving packets for each packet sent.
o 首先，引入称为Type-P-one-way-packet-arrival-count的单例度量来度量每个发送的数据包的到达数据包数。
o Then, a singleton metric, called Type-P-one-way-packet-duplication, is defined to describe a single instance of packet duplication.
o 然后，定义了一个称为Type-P-one-way-packet-duplication的单例度量来描述数据包复制的单个实例。
o Next, this singleton metric is used to define samples, Type-P-one-way-Packet-Duplication-Poisson-Stream and Type-P-one-way-Packet-Duplication-Periodic-Stream. These are introduced to measure duplication in a series of packets sent with either Poisson-distributed [RFC2680] or periodic [RFC3432] intervals between the packets.
o 接下来，该单例度量用于定义样本、类型-P-单向分组复制-泊松流和类型-P-单向分组复制-周期流。这些被引入来测量以泊松分布[RFC2680]或包之间的周期[RFC3432]间隔发送的一系列包中的重复。
o Finally, statistics that summarize the properties of these samples are introduced.
o 最后，介绍了总结这些样本特性的统计数据。
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 [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[RFC2119]中所述进行解释。
Although RFC 2119 was written with protocols in mind, the key words are used in this document for similar reasons. They are used to ensure the results of measurements from two different implementations are comparable and to note instances when an implementation could perturb the network.
尽管RFC 2119在编写时考虑了协议，但出于类似的原因，本文档中使用了关键词。它们用于确保两个不同实现的测量结果具有可比性，并用于记录一个实现可能干扰网络的实例。
When a packet is sent from one host to the other, one normally expects that exactly one copy of the packet that was sent arrives at the destination. It is, however, possible that a packet is either lost or that multiple copies arrive.
当一个数据包从一个主机发送到另一个主机时，通常期望发送的数据包的一个副本正好到达目的地。然而，有可能一个数据包丢失或多个副本到达。
In earlier work, a metric for packet loss was defined [RFC2680]. This metric distinguishes between cases where the packet arrives and where the packet does not arrive within a reasonable time. In this memo, a metric for a third outcome is defined: a single packet is sent, but multiple copies arrive.
在早期的工作中，定义了分组丢失的度量[RFC2680]。该指标区分数据包到达和数据包未在合理时间内到达的情况。在这份备忘录中，定义了第三种结果的指标：发送一个数据包，但到达多个副本。
As this document describes a case similar to the one discussed in [RFC2680], all considerations from that document on timing and accuracy apply.
由于本文件描述的情况与[RFC2680]中讨论的情况类似，因此该文件中关于时间和准确性的所有注意事项均适用。
Type-P-one-way-packet-arrival-count
Type-P-单向包到达计数
o src, the IP address of a host
o src，主机的IP地址
o dst, the IP address of a host
o dst，主机的IP地址
o T, the wire time of a packet at the source
o T、 数据包在源位置的连线时间
o T0, the maximum waiting time for a packet to arrive at the destination.
o T0，数据包到达目的地的最大等待时间。
An integer number.
整数。
Two packets are considered identical if and only if:
当且仅当满足以下条件时，两个数据包被视为相同：
o Both contain identical information fields (see Section 2.5). The recipient thus could take either packet and use the data in an application. The other packet does not contain any additional information.
o 两者都包含相同的信息字段（见第2.5节）。因此，接收者可以接受任一数据包并在应用程序中使用数据。另一个数据包不包含任何附加信息。
o Both packets appear to have been sent by one and the same host, to one and the same destination. Hosts are identified by their IP addresses.
o 两个数据包似乎都是由同一主机发送到同一目的地。主机由其IP地址标识。
The value of a Type-P-one-way-packet-arrival-count is a positive integer number indicating the number of (uncorrupted and identical) copies received by dst in the interval [T, T+T0] for a packet sent by src at time T.
Type-P-one-way-packet-arrival-count的值是正整数，表示对于src在时间T发送的分组，dst在间隔[T，T+T0]内接收的（未损坏且相同的）拷贝数。
If a packet is sent, but it is lost or does not arrive in the interval [T, T+T0], then the metric is undefined. Applications MAY report an "impossible" value (for example, -1) to indicate this condition instead of undefined.
如果发送了数据包，但数据包丢失或未在间隔[T，T+T0]内到达，则度量未定义。应用程序可能会报告一个“不可能”值（例如，-1），以指示此情况，而不是未定义。
If a packet is fragmented during transport and if, for whatever reason, reassembly does not occur, then the packet will be deemed lost. It is thus not included in the Type-P-one-way-packet-arrival-count.
如果数据包在传输过程中出现碎片，并且由于任何原因没有重新组装，则该数据包将被视为丢失。因此，它不包括在Type-P-one-way-packet-arrival-count中。
This metric counts the number of packets arriving for each packet sent. The time-out value T0 SHOULD be set to a value when the application could potentially still use the packet and would not discard it automatically.
此度量统计每个发送的数据包到达的数据包数。超时值T0应设置为应用程序可能仍然使用数据包且不会自动丢弃数据包时的值。
If this metric is used in parallel with the Packet Loss Metric [RFC2680], the value of T0 MUST be the same for both cases in order to keep the results comparable.
如果此度量与分组丢失度量[RFC2680]并行使用，则两种情况下T0的值必须相同，以保持结果的可比性。
The metric only counts packets that are not corrupted during transmission and may have been resent automatically by lower layers or intermediate devices. Packets that were corrupted during transmission but, nevertheless, still arrived at dst are not counted.
该指标仅统计传输过程中未损坏且可能已由较低层或中间设备自动重新发送的数据包。在传输过程中损坏但仍到达dst的数据包不被统计。
Clocks do have to be synchronized between src and dst such that it is possible to uniquely and accurately determine the interval [T, T+T0] at both sides.
时钟必须在src和dst之间同步，以便能够唯一准确地确定两侧的间隔[T，T+T0]。
If this metric is used in an active measurement system, the system MUST NOT send multiple packets with identical information fields in order to avoid that all packets will be declared duplicates. This metric can be used inside a passive measurement system as well, using packets generated by another source. However, if the source can send two identical packets within the interval [T, T+T0], this will be incorrectly labeled as a duplicate, resulting in a false positive. It is up to the implementor to estimate if this scenario is likely to happen and the rate of false positives that is acceptable.
如果在活动测量系统中使用此度量，系统不得发送具有相同信息字段的多个数据包，以避免所有数据包被声明为重复数据包。该度量也可以在被动测量系统中使用，使用由另一个源生成的数据包。但是，如果源可以在间隔[T，T+T0]内发送两个相同的数据包，这将被错误地标记为重复数据包，从而导致误报。由实现者来估计这种情况是否可能发生，以及可接受的误报率。
The definition of identical information fields is such that two packets are considered to be identical if they are sent from the same source and contain the same information. This does not necessarily mean that all bits in the packet are the same. For example, when a packet is replicated and the copies are transferred along different paths, the Time to Live (TTL) may be different. The implementation MUST specify which fields are compared when deciding whether or not two packets are identical.
相同信息字段的定义是，如果两个数据包从同一来源发送并包含相同信息，则认为它们是相同的。这并不一定意味着数据包中的所有位都是相同的。例如，当数据包被复制并且副本沿着不同的路径传输时，生存时间（TTL）可能不同。实现必须指定在决定两个数据包是否相同时比较哪些字段。
In the case of IPv4, these will usually be: version, ihl, identification, src, dst, protocol, some or all upper-layer protocol data.
在IPv4的情况下，这些数据通常是：版本、ihl、标识、src、dst、协议、部分或所有上层协议数据。
In IPv6, these will usually be: version, next header, source, destination, some or all upper-layer protocol data
在IPv6中，这些数据通常是：版本、下一个标头、源、目标、部分或所有上层协议数据
Note that the use of the identification field is not present in non-fragmented IPv6 packets and may not be sufficient to distinguish packets from each even in IPv4, particularly at higher transmission speeds
请注意，标识字段的使用不存在于非分段IPv6数据包中，并且可能不足以区分各个数据包，即使在IPv4中，尤其是在较高传输速度下
The basic technique to measure this metric follows the methodology described in Section 2.6 of [RFC2680] with one exception.
测量该指标的基本技术遵循[RFC2680]第2.6节所述的方法，但有一个例外。
[RFC2680] does not specify that the receiving host should be able to receive multiple copies of a single packet, as it only needs one copy to determine the metrics. Implementations for this metric should obviously be capable of receiving multiple copies.
[RFC2680]没有指定接收主机应该能够接收单个数据包的多个副本，因为它只需要一个副本来确定度量。此度量的实现显然应该能够接收多个副本。
Refer to Section 2.7 of [RFC2680].
参考[RFC2680]第2.7节。
Refer to Section 2.8 of [RFC2680].
参考[RFC2680]第2.8节。
Type-P-one-way-packet-duplication
P型单向分组复制
o src, the IP address of a host
o src，主机的IP地址
o dst, the IP address of a host
o dst，主机的IP地址
o T, the wire time of a packet at the source
o T、 数据包在源位置的连线时间
o T0, the maximum waiting time for a packet to arrive at the destination.
o T0，数据包到达目的地的最大等待时间。
An integer number.
整数。
The value of a Type-P-one-way-packet-duplication is a positive integer number indicating the number of (uncorrupted and identical) additional copies of an individual packet received by dst in the interval [T, T+T0] as sent by src at time T.
P型单向分组复制的值是正整数，表示在时间T由src发送的间隔[T，T+T0]内由dst接收的单个分组的（未损坏且相同的）附加副本的数量。
If a packet is sent and only one copy arrives in the interval [T, T+T0], then the metric is 0. If no copy arrives in this interval, then the metric is undefined. Applications MAY report an "impossible" value (for example, -1) to indicate this condition.
如果发送了一个数据包，并且在间隔[T，T+T0]中只有一个副本到达，则度量为0。如果在此时间间隔内没有副本到达，则度量未定义。应用程序可能会报告一个“不可能”值（例如，-1）来指示这种情况。
This metric is equal to:
该指标等于：
Type-P-one-way-packet-arrival-count - 1
Type-P-one-way-packet-arrival-count-1
This metric is expected to be used for applications that need to know duplication for an individual packet. All considerations regarding methodology, errors, and reporting from the previous section apply.
该指标预计将用于需要了解单个数据包重复情况的应用程序。上一节中关于方法、错误和报告的所有注意事项均适用。
Type-P-one-way-Packet-Duplication-Poisson-Stream
类型-P-单向-包复制-泊松流
o src, the IP address of a host.
o src，主机的IP地址。
o dst, the IP address of a host.
o dst，主机的IP地址。
o Ts, a time.
o 嗯，一次。
o Tf, a time. Ts and Tf specify the time interval when packets can be sent for this stream.
o Tf，一次。Ts和Tf指定可以为此流发送数据包的时间间隔。
o T0, the maximum waiting time for a packet to arrive at the destination.
o T0，数据包到达目的地的最大等待时间。
o lambda, a rate in reciprocal seconds.
o λ，以倒数秒为单位的速率。
A sequence of pairs; the elements of each pair are:
成对的序列；每对的元素包括：
o T, a time
o T、 一段时间
o Type-P-one-way-packet-arrival-count for the packet sent at T.
o Type-P-one-way-packet-arrival-count用于在T处发送的数据包。
Given Ts, Tf, and lambda, we compute a pseudo-random Poisson process beginning at or before Ts, with average-rate lambda, and ending at or after Tf. Those time values greater than or equal to Ts, and less than or equal to Tf are then selected. At each of the times in this process, we obtain the value of Type-P-one-way-packet-arrival-count. The value of the sample is the sequence made up of the resulting {time, duplication} pairs. If there are no such pairs, the sequence is of length zero, and the sample is said to be empty.
给定Ts、Tf和lambda，我们计算一个伪随机泊松过程，该过程开始于Ts或之前，平均速率为lambda，结束于Tf或之后。然后选择那些大于或等于Ts、小于或等于Tf的时间值。在这个过程中的每一次，我们都获得Type-P-one-way-packet-arrival-count的值。样本的值是由产生的{time，replication}对组成的序列。如果没有这样的对，序列的长度为零，样本称为空。
Refer to Section 3.6 of [RFC2680].
参考[RFC2680]第3.6节。
Refer to Section 3.7 of [RFC2680].
参考[RFC2680]第3.7节。
Refer to Section 3.8 of [RFC2680].
参考[RFC2680]第3.8节。
Type-P-one-way-Packet-Duplication-Periodic-Stream
类型-P-单向-包复制-周期流
o src, the IP address of a host.
o src，主机的IP地址。
o dst, the IP address of a host.
o dst，主机的IP地址。
o Ts, a time.
o 嗯，一次。
o Tf, a time. Ts and Tf specify the time interval when packets can be sent for this stream.
o Tf，一次。Ts和Tf指定可以为此流发送数据包的时间间隔。
o T0, the maximum waiting time for a packet to arrive at the destination.
o T0，数据包到达目的地的最大等待时间。
o lambda, a rate in reciprocal seconds.
o λ，以倒数秒为单位的速率。
A sequence of pairs; the elements of each pair are:
成对的序列；每对的元素包括：
o T, a time
o T、 一段时间
o Type-P-one-way-packet-arrival-count for the packet sent at T.
o Type-P-one-way-packet-arrival-count用于在T处发送的数据包。
At time Ts, we start sending packets with a constant-rate lambda, until time Tf. For each packet sent, we obtain the value of Type-P-one-way-packet-arrival-count. The value of the sample is the sequence made up of the resulting {time, duplication} pairs. If there are no such pairs, the sequence is of length zero and the sample is said to be empty.
在时间Ts，我们开始以恒定速率lambda发送数据包，直到时间Tf。对于发送的每个数据包，我们获得Type-P-one-way-packet-arrival-count的值。样本的值是由产生的{time，replication}对组成的序列。如果没有这样的对，序列的长度为零，样本称为空。
Refer to Section 4.5 of [RFC3432].
参考[RFC3432]第4.5节。
Refer to Section 4.6 of [RFC3432].
参考[RFC3432]第4.6节。
Refer to Section 4.7 of [RFC3432].
参考[RFC3432]第4.7节。
Note: the statistics described in this section can be used for both Type-P-one-way-Packet-Duplication-Poisson-Stream and Type-P-one-way-Packet-Duplication-Periodic-Stream. The application SHOULD report which sample was used as input.
注：本节中描述的统计数据可用于P-单向数据包重复-泊松流和P-单向数据包重复-周期流。应用程序应报告用作输入的样本。
This statistic gives the fraction of additional packets that arrived in a stream.
此统计信息给出了到达流中的附加数据包的分数。
Given a Type-P-one-way-Packet-Duplication-Poisson-Stream, one first removes all values of Type-P-one-way-Packet-Duplication that are undefined. For the remaining pairs in the stream, one calculates: (Sum Type-P-one-way-packet-arrival-count/Number of pairs left) - 1 (In other words, (number of packets received)/(number of packets sent and not lost).)
给定一个P-one-way-Packet-Duplication-Poisson-Stream类型，首先删除所有未定义的P-one-way-Packet-Duplication类型的值。对于流中的其余对，计算：（Sum Type-P-one-way-packet-arrival-count/剩余对数）-1（换句话说，（接收到的包数）/（发送和未丢失的包数）
The number can be expressed as a percentage.
这个数字可以用百分比表示。
Note: this statistic is the equivalent to the Y.1540 IPDR [Y1540].
注：该统计数据相当于Y.1540 IPDR[Y1540]。
This statistic gives the fraction of packets that was duplicated (one or more times) in a stream.
此统计信息给出流中重复（一次或多次）的数据包的分数。
Given a Type-P-one-way-Packet-Duplication-Poisson-Stream, one first removes all values of Type-P-one-way-packet-arrival-count that are undefined. For the remaining pairs in the stream, one counts the number of pairs with Type-P-one-way-packet-arrival-count greater than 1. Then, one calculates the fraction of packets that meet this criterion as a fraction of the total. (In other words: (number of duplicated packets)/(number of packets sent and not lost).)
给定一个P-one-way-Packet-replication-Poisson-Stream类型，首先删除所有未定义的P-one-way-Packet-arrival-count类型的值。对于流中的其余对，计算类型为P-one-way-packet-arrival-count大于1的对的数量。然后，计算满足此标准的数据包的分数作为总数的分数。（换句话说：（重复数据包数）/（已发送且未丢失的数据包数）
The number can be expressed as a percentage.
这个数字可以用百分比表示。
Note: this statistic is the equivalent of the Y.1540 RIPR [Y1540].
注：该统计数据相当于Y.1540 RIPR[Y1540]。
Consider a stream of 4 packets, sent as:
考虑一个4个数据包流，发送如下：
(1, 2, 3, 4)
(1, 2, 3, 4)
and arriving as:
并以下列方式抵达：
o Case 1: (1, 2, 3, 4)
o 案例1：（1,2,3,4）
o Case 2: (1, 1, 2, 2, 3, 3, 4, 4)
o 案例2：（1,1,2,2,3,3,4,4）
o Case 3: (1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4)
o 案例3：（1,1,1,2,2,3,3,4,4,4）
o Case 4: (1, 1, 1, 2, 3, 3, 3, 4)
o 案例4：（1,1,1,2,3,3,4）
Case 1: No packets are duplicated in a stream, and both the Type-P-one-way-packet-duplication-fraction and the Type-P-one-way-packet-replicated-packet-rate are 0.
情况1：流中没有重复的数据包，并且Type-P-one-way-packet-replication-fraction和Type-P-one-way-packet-replicated-packet-rate都是0。
Case 2: Every packet is duplicated once, and the Type-P-one-way-packet-duplication-fraction is 100%. The Type-P-one-way-replicated-packet-rate is 100%, too.
案例2：每个包复制一次，类型P-单向-包复制-分数为100%。P型单向复制包速率也为100%。
Case 3: Every packet is duplicated twice, so the Type-P-one-way-packet-duplication-fraction is 200%. The Type-P-one-way-replicated-packet-rate is still 100%.
案例3：每个数据包复制两次，因此类型-P-单向数据包复制分数为200%。P型单向复制包速率仍然是100%。
Case 4: Half the packets are duplicated twice and the other half are not duplicated. The Type-P-one-way-packet-duplication-fraction is again 100%, and this number does not show the difference with case 2. However, the Type-P-one-way-packet-replicated-packet-rate is 50% in this case and 100% in case 2.
情况4：一半的数据包重复两次，另一半不重复。类型-P-单向-packet-replication-fraction再次是100%，并且该数字没有显示与情况2的差异。然而，在这种情况下，P型单向分组复制分组速率为50%，在情况2中为100%。
However, the Type-P-one-way-packet-duplication-rate will not show the difference between cases 2 and 3. For this, one has to look at the Type-P-one-way-packet-duplication-fraction.
但是，Type-P-one-way-packet-replication-rate不会显示情况2和情况3之间的差异。为此，我们必须查看类型P-one-way-packet-replication-fraction。
Finally, note that the order in which the packets arrived does not affect the results. For example, these variations of case 2:
最后，请注意，数据包到达的顺序不会影响结果。例如，情况2的这些变化：
o Case 2a: (1, 1, 2, 2, 3, 3, 4, 4)
o 案例2a：（1,1,2,2,3,3,4,4）
o Case 2b: (1, 2, 3, 4, 1, 2, 3, 4)
o 案例2b：（1,2,3,4,1,2,3,4）
o Case 2c: (1, 2, 3, 4, 4, 3, 2, 1)
o 案例2c：（1,2,3,4,4,3,2,1）
(as well as any other permutation) all yield the same results for Type-P-one-way-packet-duplication-fraction and the Type-P-one-way-replicated-packet-rate.
（以及任何其他排列）对于Type-P-one-way-packet-replication-fraction和Type-P-one-way-replicated-packet-rate都产生相同的结果。
Conducting Internet measurements raises both security and privacy concerns. This memo does not specify an implementation of the metrics, so it does not directly affect the security of the Internet nor of applications that run on the Internet. However, implementations of these metrics must be mindful of security and privacy concerns.
进行互联网测量会引起安全和隐私问题。此备忘录未指定指标的实现，因此它不会直接影响Internet或在Internet上运行的应用程序的安全性。然而，这些指标的实现必须考虑安全和隐私问题。
There are two types of security concerns: potential harm caused by the measurements and potential harm to the measurements. The measurements could cause harm because they are active, and they inject packets into the network. The measurement parameters MUST be carefully selected so that the measurements inject trivial amounts of additional traffic into the networks they measure. If they inject "too much" traffic, they can skew the results of the measurement, and in extreme cases, cause congestion and denial of service.
有两种类型的安全问题：由测量引起的潜在危害和对测量的潜在危害。这些测量可能会造成危害，因为它们是活动的，并且会将数据包注入网络。必须仔细选择测量参数，以便测量将少量的额外流量注入到它们测量的网络中。如果它们注入了“太多”的流量，它们可能会扭曲测量结果，在极端情况下，会导致拥塞和拒绝服务。
The measurements themselves could be harmed by routers giving measurement traffic a different priority than "normal" traffic or by an attacker injecting artificial measurement traffic. If routers can recognize measurement traffic and treat it separately, the measurements will not reflect actual user traffic. If an attacker injects artificial traffic that is accepted as legitimate, the loss rate will be artificially lowered. Therefore, the measurement methodologies SHOULD include appropriate techniques to reduce the probability that measurement traffic can be distinguished from "normal" traffic. Authentication techniques, such as digital signatures, may be used where appropriate to guard against injected traffic attacks.
路由器给予测量流量不同于“正常”流量的优先级，或者攻击者注入人工测量流量，可能会损害测量本身。如果路由器能够识别测量流量并单独处理，那么测量将不会反映实际的用户流量。如果攻击者注入被认为合法的人工流量，则损失率将被人为降低。因此，测量方法应包括适当的技术，以降低测量流量可与“正常”流量区分的概率。在适当的情况下，可以使用诸如数字签名之类的认证技术来防止注入流量攻击。
The privacy concerns of network measurement are limited by the active measurements described in this memo. Unlike passive measurements, there can be no release of existing user data.
网络测量的隐私问题受到本备忘录中所述的主动测量的限制。与被动测量不同，不能释放现有用户数据。
IANA has registered the metrics defined in this document in the IP Performance Metrics (IPPM) Metrics Registry, see [RFC4148].
IANA已在IP性能度量（IPPM）度量注册表中注册了本文档中定义的度量，请参阅[RFC4148]。
The idea to write this document came up in a meeting with Al Morton, Stanislav Shalunov, Emile Stephan, and the author on the IPPM reporting document.
撰写本文件的想法是在与Al Morton、Stanislav Shalunov、Emile Stephan和IPPM报告文件的作者会面时提出的。
This document relies heavily on [RFC2680], and the author would like to thank the authors of that document for writing it.
本文档严重依赖[RFC2680]，作者谨感谢该文档的作者撰写本文档。
Finally, thanks are due to Lars Eggert, Al Morton, Martin Swany, and Matt Zekauskas for their comments.
最后，感谢Lars Eggert、Al Morton、Martin Swany和Matt Zekauskas的评论。
[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。
[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way Packet Loss Metric for IPPM", RFC 2680, September 1999.
[RFC2680]Almes，G.，Kalidini，S.，和M.Zekauskas，“IPPM的单向数据包丢失度量”，RFC 2680，1999年9月。
[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network performance measurement with periodic streams", RFC 3432, November 2002.
[RFC3432]Raisanen，V.，Grotefeld，G.，和A.Morton，“周期流的网络性能测量”，RFC 3432，2002年11月。
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis, "Framework for IP Performance Metrics", RFC 2330, May 1998.
[RFC2330]Paxson，V.，Almes，G.，Mahdavi，J.，和M.Mathis，“IP性能度量框架”，RFC 2330，1998年5月。
[RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics Registry", BCP 108, RFC 4148, August 2005.
[RFC4148]Stephan，E.“IP性能度量（IPPM）度量注册表”，BCP 108，RFC 4148，2005年8月。
[Y1540] "Y.1540 ITU-T Recommendation Y.1540 (2007), Internet protocol data communication service IP packet transfer and availability performance parameters.", 2007.
[Y1540]“Y.1540 ITU-T建议Y.1540（2007），互联网协议数据通信服务IP数据包传输和可用性性能参数”，2007年。
Author's Address
作者地址
Henk Uijterwaal RIPE NCC Singel 258 1016 AB Amsterdam The Netherlands
荷兰阿姆斯特丹亨克Uijterwaal成熟NCC Singel 258 1016 AB
Phone: +31 20 535 4444
EMail: henk@ripe.net
Phone: +31 20 535 4444
EMail: henk@ripe.net