Internet Engineering Task Force (IETF) S. Baillargeon
Request for Comments: 6802 C. Flinta
Category: Informational A. Johnsson
ISSN: 2070-1721 Ericsson
November 2012
Internet Engineering Task Force (IETF) S. Baillargeon
Request for Comments: 6802 C. Flinta
Category: Informational A. Johnsson
ISSN: 2070-1721 Ericsson
November 2012
Ericsson Two-Way Active Measurement Protocol (TWAMP) Value-Added Octets
爱立信双向主动测量协议（TWAMP）增值八位字节
Abstract
摘要
This memo describes an extension to the Two-Way Active Measurement Protocol (TWAMP). Specifically, it extends the TWAMP-Test protocol, which identifies and manages packet trains, in order to measure capacity metrics like the available path capacity, tight section capacity, and UDP delivery rate in the forward and reverse path directions.
本备忘录描述了双向主动测量协议（TWAMP）的扩展。具体而言，它扩展了识别和管理数据包序列的TWAMP测试协议，以测量可用路径容量、紧段容量以及正向和反向路径方向上的UDP交付率等容量指标。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
This document is a product of the Internet Engineering Task Force (IETF). It has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
本文件是互联网工程任务组（IETF）的产品。互联网工程指导小组（IESG）已批准将其出版。并非IESG批准的所有文件都适用于任何级别的互联网标准；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/rfc6802.
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/rfc6802.
Copyright Notice
版权公告
Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2012 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 ....................................................2
1.1. Requirements Language ......................................3
2. Purpose and Scope ...............................................3
3. Capacity Measurement Principles .................................4
4. TWAMP-Control Extensions ........................................5
4.1. Additional Considerations ..................................6
5. Extended TWAMP-Test .............................................6
5.1. Sender Behavior ............................................6
5.1.1. Packet Timings ......................................7
5.1.2. Session-Sender Packet Format ........................7
5.2. Reflector Behavior ........................................12
5.2.1. Session-Reflector Packet Format ....................13
5.3. Additional Considerations .................................13
6. Experiments ....................................................14
7. Security Considerations ........................................14
8. Acknowledgements ...............................................14
9. References .....................................................15
9.1. Normative References ......................................15
9.2. Informative References ....................................15
1. Introduction ....................................................2
1.1. Requirements Language ......................................3
2. Purpose and Scope ...............................................3
3. Capacity Measurement Principles .................................4
4. TWAMP-Control Extensions ........................................5
4.1. Additional Considerations ..................................6
5. Extended TWAMP-Test .............................................6
5.1. Sender Behavior ............................................6
5.1.1. Packet Timings ......................................7
5.1.2. Session-Sender Packet Format ........................7
5.2. Reflector Behavior ........................................12
5.2.1. Session-Reflector Packet Format ....................13
5.3. Additional Considerations .................................13
6. Experiments ....................................................14
7. Security Considerations ........................................14
8. Acknowledgements ...............................................14
9. References .....................................................15
9.1. Normative References ......................................15
9.2. Informative References ....................................15
The notion of embedding a number of meaningful fields in the padding octets has been established as a viable methodology for carrying additional information within the TWAMP-Test protocol running between a Session-Sender and a Session-Reflector [RFC5357] [RFC6038].
在填充八位字节中嵌入大量有意义字段的概念已被确立为在会话发送方和会话反射器之间运行的TWAMP测试协议中承载附加信息的可行方法[RFC5357][RFC6038]。
This memo describes an optional extension to the Two-Way Active Measurement Protocol (TWAMP) [RFC5357]. It is called the Ericsson TWAMP Value-Added Octets feature. This memo defines version 1.
本备忘录描述了双向主动测量协议（TWAMP）[RFC5357]的可选扩展。它被称为爱立信TWAMP增值八位字节功能。本备忘录定义了版本1。
This feature enables the controller host to measure capacity metrics like the IP-type-P available path capacity (APC) [RFC5136], IP-layer tight section capacity (TSC) [Y1540], and UDP delivery rate on both forward and reverse paths using a single TWAMP test session. The actual method to calculate the APC, TSC, or the UDP delivery rate from packet-level performance data is not discussed in this memo.
此功能使控制器主机能够使用单个TWAMP测试会话测量正向和反向路径上的容量指标，如IP-type-P可用路径容量（APC）[RFC5136]、IP层紧密段容量（TSC）[Y1540]和UDP交付速率。本备忘录中未讨论从数据包级性能数据计算APC、TSC或UDP传递率的实际方法。
The Valued-Added Octets feature consists of new behaviors for the Session-Sender and Session-Reflector and a set of value-added octets of information that are placed at the beginning of the Packet Padding [RFC5357] or immediately after the Server Octets in the Packet Padding (to be reflected) [RFC6038] by the Session-Sender and are reflected or returned by the Session-Reflector. The length of the value-added octets in version 1 is 10 octets. The Valued-Added
增值八位字节功能包括会话发送方和会话反射器的新行为以及一组信息增值八位字节，这些信息放在数据包填充[RFC5357]的开头或数据包填充（待反映）中服务器八位字节的后面。[RFC6038]由会话发送方发送，并由会话反射器反射或返回。版本1中增值八位字节的长度为10个八位字节。增值税
Octets feature does not change the basic roles and functions of the TWAMP hosts, which are still responsible to include timestamp(s) and sequence number(s) in the test packets.
八位字节特性不会改变TWAMP主机的基本角色和功能，它们仍然负责在测试数据包中包含时间戳和序列号。
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。
The purpose of this memo is to describe the Ericsson TWAMP Valued-Added Octets feature (version 1) for TWAMP [RFC5357].
本备忘录旨在描述爱立信TWAMP[RFC5357]的增值八位字节功能（第1版）。
The scope of the memo is limited to specifications of the following enhancements:
备忘录的范围仅限于以下增强功能的规范：
o The definition of a structure for embedding a sequence of value-added fields at the beginning of the Packet Padding [RFC5357] or Packet Padding (to be reflected) [RFC6038] in the TWAMP-Test packets
o 在TWAMP测试数据包中的数据包填充[RFC5357]或数据包填充（待反映）[RFC6038]开始处嵌入一系列增值字段的结构定义
o The definition of new Session-Sender and Session-Reflector behaviors
o 新会话发送方和会话反射方行为的定义
The motivation for this feature is to enable the measurement of capacity metrics on both the forward and reverse paths using a single TWAMP test session. Multiple TWAMP test sessions between a controller and a responder with different Diffserv Code Points (DSCPs) may also be used to evaluate the QoS impacts on the capacity metrics.
此功能的动机是使用单个TWAMP测试会话来测量正向和反向路径上的容量度量。控制器和具有不同区分服务码点（DSCP）的响应者之间的多个TWAMP测试会话也可用于评估QoS对容量度量的影响。
This memo captures the prototype presented and demonstrated at IETF 80. It may be used as a reference for future work or may be used during benchmark analysis to compare the accuracy or performance of the available path capacity estimates under various condition or use cases.
本备忘录捕获了IETF 80上展示和演示的原型。它可以用作未来工作的参考，也可以在基准分析期间用于比较各种条件或用例下可用路径容量估计的准确性或性能。
This memo does not extend the standard modes of operation through assignment of a new value in the Modes field (see Section 3.1 of [RFC4656] for the format of the Server Greeting message). This memo does not define a vendor-specific or experimental mode since the Modes field as currently defined does not explicitly reserve a value or range of values for this purpose.
本备忘录不通过在模式字段中分配新值来扩展标准操作模式（有关服务器问候语的格式，请参见[RFC4656]第3.1节）。由于当前定义的“模式”字段未明确保留用于此目的的值或值范围，因此本备忘录未定义特定于供应商的模式或实验模式。
This memo assumes the TWAMP controller is capable to send test packets with value-added padding octets and the TWAMP responder is configured to interpret the value-added padding octets embedded in each TWAMP-Test packet. Bootstrapping such behavior at the TWAMP responder is implementation specific. By default, the feature MUST be disabled on the TWAMP host. The Value-Added Octets feature MUST be deployed in an environment where both controller and responder are managed by the same administrative entity and such entity has established an agreement to operate the Value-Added Octets feature between the pair of hosts or between specific UDP endpoints between the pair of hosts. See Sections 4 and 5.3 for additional considerations.
本备忘录假设TWAMP控制器能够发送带有增值填充八位字节的测试数据包，并且TWAMP响应器配置为解释嵌入在每个TWAMP测试数据包中的增值填充八位字节。在TWAMP响应程序上引导此类行为是特定于实现的。默认情况下，必须在TWAMP主机上禁用该功能。增值八位字节功能必须部署在以下环境中：控制器和响应程序均由同一管理实体管理，且该实体已建立协议，以在主机对之间或主机对之间的特定UDP端点之间操作增值八位字节功能。更多注意事项见第4节和第5.3节。
The Value-Added Octets Version 1 feature is intended to work in conjunction with any TWAMP modes. When the Server and Control-Client are configured or have agreed to use the Value-Added Octets Version 1 feature, then the Control-Client, the Server, the Session-Sender, and the Session-Reflector must all conform to the requirements of that feature, as identified below.
增值八位字节版本1功能旨在与任何TWAMP模式结合使用。当服务器和控制客户端已配置或同意使用增值八位字节版本1功能时，控制客户端、服务器、会话发送器和会话反射器都必须符合该功能的要求，如下所示。
Most capacity estimation methods for APC [RRBNC] [PDM] [ENHJMMB] [SBW] and for UDP delivery rate need to send and receive packets in groups, called "packet trains" or simply "trains". Each train is sent at a specific transmission rate in a given direction. These trains must be identified within each bidirectional test session stream.
对于APC[RRBNC][PDM][ENHJMMB][SBW]和UDP交付速率，大多数容量估计方法都需要分组发送和接收数据包，称为“数据包序列”或简称“序列”。每列列车在给定方向上以特定的传输速率发送。必须在每个双向测试会话流中识别这些序列。
The first measurement principle is to send multiple trains within a test session stream from one IP node to another IP node in order to estimate the APC, TSC, or UDP delivery rate in the forward direction. Each train consists of a group of test packets that are separated from each other by a packet interval, as shown in the figure below. The packet interval is measured using either the first bit or the last bit of two consecutive packets.
第一个测量原理是在测试会话流中从一个IP节点向另一个IP节点发送多个序列，以估计前进方向上的APC、TSC或UDP交付速率。每列列车由一组测试数据包组成，这些数据包通过数据包间隔相互分离，如下图所示。使用两个连续数据包的第一位或最后一位来测量数据包间隔。
tt tt tt
|<---------->| |<---------->| |<---------->|
| | | | | |
+------------+ +------------+ +------------+
| Packet 1 | | Packet 2 | | Packet 3 |
+------------+ +------------+ +------------+
| | |
|<--------------------->|<--------------------->|
packet interval 1 packet interval 2
tt tt tt
|<---------->| |<---------->| |<---------->|
| | | | | |
+------------+ +------------+ +------------+
| Packet 1 | | Packet 2 | | Packet 3 |
+------------+ +------------+ +------------+
| | |
|<--------------------->|<--------------------->|
packet interval 1 packet interval 2
The test packet size and interval between consecutive packets for each train sent by the Session-Sender and reflected by the Session-Reflector MUST be calculated and determined by the controller or an application or entity communicating with the controller. The packet size and interval MAY vary within a train and/or between trains. Determination of the packet size and interval is implementation specific.
控制器或与控制器通信的应用程序或实体必须计算并确定由会话发送器发送并由会话反射器反映的每列列车的测试数据包大小和连续数据包之间的间隔。数据包大小和间隔在一列和/或两列之间可能不同。包大小和间隔的确定是特定于实现的。
The transmission time tt to send one packet (i.e., determined by the interface speed and the IP packet size) is also shown in the figure above. Observe that the packet interval MUST be larger than or equal to tt.
发送一个分组的传输时间tt（即，由接口速度和IP分组大小确定）也如上图所示。请注意，数据包间隔必须大于或等于tt。
At the Session-Reflector, each received test packet within a forward train is time stamped. This provides a second set of packet interval values. Methods for measuring the APC, TSC, and UDP delivery rate use the packet intervals obtained from both endpoints in the estimation process. The method of measuring the UDP delivery rate may also require the rate of packet loss. The estimation process itself, as well as any requirements on software or hardware, is implementation specific.
在会话反射器处，前向序列内的每个接收到的测试包都带有时间戳。这提供了第二组数据包间隔值。用于测量APC、TSC和UDP交付速率的方法使用在估计过程中从两个端点获得的数据包间隔。测量UDP传输速率的方法可能还需要数据包丢失率。评估过程本身以及对软件或硬件的任何要求都是特定于实现的。
The second measurement principle is referred to as "self-induced congestion". According to this principle, in order to measure APC, TSC, and UDP delivery rates, some trains MUST cause momentary congestion on the network path. In essence, this means that some trains MUST be sent at a higher rate than what is available on the network path.
第二个测量原理称为“自感拥塞”。根据这一原理，为了测量APC、TSC和UDP传输速率，某些列车必须在网络路径上造成瞬时拥塞。本质上，这意味着某些列车的发送速率必须高于网络路径上的可用速率。
In order to fulfill the above measurement principles and to measure the APC, TSC, and UDP delivery rates in the reverse direction, the test packets at the Session-Reflector MUST be regrouped into trains and then transmitted back to the Session-Sender with a provided packet interval.
为了实现上述测量原则，并测量反向的APC、TSC和UDP交付速率，会话反射器处的测试数据包必须重新组合成序列，然后以规定的数据包间隔发送回会话发送器。
TWAMP connection establishment follows the procedure defined in Section 3.1 of [RFC4656] and Section 3.1 of [RFC5357]. The TWAMP-Control protocol [RFC5357] uses the Modes field to identify and select specific communication capabilities. According to the standard specifications, the Value-Added Octets feature requires one new bit position (and value) to identify the ability of the Server/Session-Reflector to read and act upon the new fields in the value-added octets. Such bit position (and value) is not defined in this memo. Bootstrapping the TWAMP Value-Added Octets Version 1 feature is implementation specific.
TWAMP连接建立遵循[RFC4656]第3.1节和[RFC5357]第3.1节中定义的程序。TWAMP控制协议[RFC5357]使用模式字段来识别和选择特定的通信能力。根据标准规范，增值八位字节功能需要一个新的位位置（和值），以识别服务器/会话反射器读取增值八位字节中的新字段并对其进行操作的能力。该位位置（和值）未在本备忘录中定义。引导TWAMP增值八位字节版本1功能是特定于实现的。
Both the Reflect Octets mode and Symmetrical Size mode MAY be selected to ensure the reflection of the value-added padding octets by the Session-Reflector and symmetrical size TWAMP-Test packets in the forward and reverse directions of transmission.
可以选择反射八位字节模式和对称大小模式，以确保会话反射器和对称大小TWAMP测试分组在传输的正向和反向上反射增值填充八位字节。
In the TWAMP control architecture, the TWAMP reflector (server) signals the modes it wishes to operate and the TWAMP controller (control-client) selects the mode or modes supported by the responder. This feature is designed to retain backward compatibility with the original TWAMP-Control and TWAMP-Test protocols. As an alternative, the user may opt for TWAMP Light architecture, which does not require the TWAMP-Control protocol.
在TWAMP控制体系结构中，TWAMP反射器（服务器）向其希望操作的模式发送信号，TWAMP控制器（控制客户端）选择响应者支持的一种或多种模式。此功能旨在保持与原始TWAMP控制和TWAMP测试协议的向后兼容性。作为替代方案，用户可以选择不需要TWAMP控制协议的TWAMP灯光体系结构。
The methods to determine if the Value-Added Octets feature is supported on a TWAMP reflector is implementation specific. When the Value-Added Octets feature is not supported on a TWAMP reflector, the TWAMP controller MUST NOT select the Value-Added Octets feature and MUST NOT include any value-added octets in the test packets. If the TWAMP controller inadvertently sends value-added octets in the test packets to a TWAMP responder that does not support such feature, the TWAMP responder shall treat the value-added octets as regular padding octets and return the test packets as quickly as possible to the Session-Sender as defined in [RFC5357].
确定TWAMP反射器是否支持增值八位字节功能的方法是特定于实现的。当TWAMP反射器不支持增值八位字节功能时，TWAMP控制器不得选择增值八位字节功能，且不得在测试数据包中包含任何增值八位字节。如果TWAMP控制器无意中将测试数据包中的增值八位字节发送给不支持该功能的TWAMP应答器，则TWAMP应答器应将增值八位字节视为常规填充八位字节，并按照[RFC5357]中的定义尽快将测试数据包返回给会话发送器。
The forward and reverse APC, TSC, and UDP delivery rate measurement characteristics depend on the size and packet intervals of the test packets. This memo allows variable packet sizes and packet intervals between trains and even between packets in the same train. The functionality is described below.
正向和反向APC、TSC和UDP传递速率测量特性取决于测试数据包的大小和数据包间隔。此备忘录允许在列车之间，甚至在同一列车的数据包之间，可变数据包大小和数据包间隔。下面描述了该功能。
The TWAMP-Test protocol carrying the value-added padding octets is identical to TWAMP [RFC5357] except for the definition of the first 10 octets in the Packet Padding that the Session-Sender expects to be reflected. The new octets define fields for Value-Added Octets Version, Flags, Last Sequence Number in Train, and Desired Reverse Packet Interval. Each of these fields are described in detail below.
携带增值填充八位字节的TWAMP测试协议与TWAMP[RFC5357]相同，除了会话发送方希望反映的数据包填充中前10个八位字节的定义。新的八位字节定义了增值八位字节版本、标志、序列中的最后序列号和所需的反向数据包间隔的字段。下面详细描述这些字段中的每一个。
The Session-Sender and Session-Reflector behaviors are also modified.
还修改了会话发送者和会话反射者的行为。
This section describes the extensions to the behavior of the TWAMP Session-Sender.
本节介绍对TWAMP会话发送方行为的扩展。
The Send Schedule is not utilized in TWAMP, and this is unchanged in this memo.
TWAMP中未使用发送计划，此备忘中也未更改。
The Session-Sender packet format follows the same procedure and guidelines as defined in TWAMP [RFC5357] and TWAMP Reflect Octets and Symmetrical Size Features [RFC6038].
会话发送方数据包格式遵循TWAMP[RFC5357]和TWAMP反射八位字节和对称大小特征[RFC6038]中定义的相同程序和准则。
This feature allows the Session-Sender to set the first few octets in the TWAMP-Test Packet Padding with information to communicate value-added padding version number, flag bits, sequence number of the last packet in a train, and desired reverse packet interval (or per-packet waiting time) for the reverse path direction of transmission.
此功能允许会话发送方使用信息设置TWAMP测试数据包填充中的前几个八位字节，以传递增值填充版本号、标志位、序列中最后一个数据包的序列号，以及传输反向路径方向所需的反向数据包间隔（或每个数据包等待时间）。
The Valued-Added Octets feature must be placed immediately after the TWAMP header or immediately after any new field that could be added to the TWAMP header or added to the beginning of the padding octets in the future. Therefore, the placement of the first bit from the valued-added octets depends on the mode(s) being selected.
增值八位字节功能必须紧跟在TWAMP头之后，或者紧跟在将来可能添加到TWAMP头或添加到填充八位字节开头的任何新字段之后。因此，来自加值八位字节的第一位的位置取决于所选择的模式。
A version number and a sequence of flag bits are defined at the very beginning of the value-added padding octets. The version number identifies the version of the value-added padding octets and meaning of the flag bits and corresponding fields. Each flag bit indicates if a specific field is used in the valued-added padding octets. The version number and flag bits provide an effective method for extracting information at Session-Reflector and Session-Sender. This document defines version 1 with two flag bits: L and I.
版本号和标志位序列在增值填充八位字节的最开始处定义。版本号标识增值填充八位字节的版本以及标志位和相应字段的含义。每个标志位指示是否在加值填充八位字节中使用特定字段。版本号和标志位为在会话反射器和会话发送器处提取信息提供了一种有效的方法。本文档使用两个标志位定义了版本1：L和I。
The format of the test packet depends on the TWAMP modes. The Value-Added Octets Version 1 feature is intended to work with any TWAMP modes.
测试数据包的格式取决于TWAMP模式。增值八位字节版本1功能旨在与任何TWAMP模式一起使用。
The Session-Sender SHALL use the following TWAMP-Test packet format when the Value-Added Octets Version 1 feature is selected in conjunction with the Unauthenticated mode:
当结合未经验证的模式选择增值八位字节版本1功能时，会话发送方应使用以下TWAMP测试数据包格式：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | Ver |L|I| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Seqno In Train |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Desired Reverse Packet Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Packet Padding |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | Ver |L|I| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Seqno In Train |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Desired Reverse Packet Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Packet Padding |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Session-Sender SHALL use the following TWAMP-Test packet format when the Value-Added Octets Version 1 feature is selected in conjunction with the Unauthenticated mode, Symmetrical Size mode, and Reflect Octets mode:
当结合未经验证模式、对称大小模式和反射八位字节模式选择增值八位字节版本1功能时，会话发送方应使用以下TWAMP测试数据包格式：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| |
| MBZ (27 octets) |
| |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Ver |L|I| Reserved | Last... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Seqno in Train | Desired... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reverse Packet Interval | Additional... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packet Padding |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| |
| MBZ (27 octets) |
| |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Ver |L|I| Reserved | Last... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Seqno in Train | Desired... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reverse Packet Interval | Additional... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packet Padding |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Session-Sender SHALL use the following TWAMP-Test packet format when the Value-Added Octets Version 1 feature is selected in conjunction with the Unauthenticated mode, Symmetrical Size mode, and Reflect Octets mode with a non-zero value in the Server Octets field:
当选择增值八位字节第1版功能时，会话发送方应使用以下TWAMP测试数据包格式，同时选择未经验证模式、对称大小模式，并在服务器八位字节字段中使用非零值反映八位字节模式：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| |
| MBZ (27 octets) |
| |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Server Octets | Ver |L|I|...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Last Seqno in... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Train | Desired Reverse Packet... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval | Additional Packet Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| |
| MBZ (27 octets) |
| |
| |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Server Octets | Ver |L|I|...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Last Seqno in... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Train | Desired Reverse Packet... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interval | Additional Packet Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In the mode using Reflect Octets illustrated above, the value-added padding octets are embedded in the Packet Padding (to be reflected).
在上面所示的使用反射八位字节的模式中，增值填充八位字节嵌入在分组填充（待反射）中。
The Version (Ver) field MUST be encoded in the first 4 bits. It identifies the version number of the value-added padding octets and meaning of the flag bits and the corresponding fields. This memo defines version 1 with two flag bits: L and I. When the Value-Added Octets Version 1 feature is selected, the Session-Sender MUST set the Ver field to 1.
版本（Ver）字段必须在前4位进行编码。它标识增值填充八位字节的版本号以及标志位和相应字段的含义。此备忘录使用两个标志位定义版本1：L和I。选择增值八位字节版本1功能时，会话发送方必须将版本字段设置为1。
The 2 bits after the Version field are used for flags: L and I.
版本字段后的2位用于标志：L和I。
The Last Seqno in Train bit (L) is the first flag. When the Value-Added Octets Version 1 feature is selected, the Session-Sender MAY set the Last Seqno in Train bit L to 1.
列车位（L）中的最后一个Seqno是第一个标志。当选择增值八位字节版本1功能时，会话发送方可将序列位L中的最后一个Seqno设置为1。
The Desired Reverse Packet Interval bit (I) is the second flag. When the Value-Added Octets Version 1 feature is selected, the Session-Sender MAY set the Desired Reverse Packet Interval bit I to 1.
期望的反向分组间隔位（I）是第二个标志。当选择增值八位字节版本1功能时，会话发送方可将所需的反向分组间隔位I设置为1。
The Reserved field is reserved for future use. All 10 bits of the Reserved field MUST be transmitted as zero by the Session-Sender.
保留字段保留供将来使用。会话发送方必须将保留字段的所有10位传输为零。
If the Last Seqno in Train bit is set to 1, then the Last Seqno in Train field MUST contain an unsigned 32-bit integer generated by the Session-Sender. It MUST indicate the expected sequence number of the last packet in the train. It SHOULD be used by the Session-Sender and Session-Reflector to identify the train to which a test packet belongs. The packets belonging to a train are determined by observing the test packet Sequence Number in relation to the Last Seqno in Train. The Last Seqno in Train MUST be higher or equal to Sequence Number of the packet. It must also be higher than the Last Seqno in Train for the previous train. If the L bit is set to 0, the Session-Sender shall set all the bits in the Last Seqno in Train field to zero.
如果序列中的最后一个Seqno位设置为1，则序列中的最后一个Seqno字段必须包含会话发送方生成的无符号32位整数。它必须指示列车上最后一个数据包的预期序列号。会话发送方和会话反射器应使用它来识别测试数据包所属的列车。通过观察与列车中最后一个序列号相关的测试数据包序列号，确定属于列车的数据包。序列中的最后一个序列号必须高于或等于数据包的序列号。它还必须高于上一列车的最后一个序列号。如果L位设置为0，会话发送方应将列车字段中最后一个序列号中的所有位设置为0。
If the Desired Reverse Packet Interval bit is set to 1, then the Desired Reverse Packet Interval field MUST contain an unsigned 32 bit integer generated by the Session-Sender. It MUST indicate the desired packet interval (or the waiting time) that the Session-Reflector SHOULD use when transmitting the reflected test packets towards the Session-Sender. The value 0 means the Session-Reflector SHOULD return the test packet to the Session-Sender as quickly as possible. The format of this field MUST be a fractional part of a second as defined in the One-Way Active Measurement Protocol (OWAMP) [RFC4656]. If the I bit is set to 0, the Session-Sender shall set all the bits in the Desired Reverse Packet Interval field to zero.
如果所需反向数据包间隔位设置为1，则所需反向数据包间隔字段必须包含会话发送方生成的无符号32位整数。它必须指示会话反射器在向会话发送器发送反射的测试数据包时应使用的期望数据包间隔（或等待时间）。值0表示会话反射器应尽快将测试数据包返回给会话发送器。此字段的格式必须是单向主动测量协议（OWAMP）[RFC4656]中定义的秒的小数部分。如果I位设置为0，会话发送方应将所需反向数据包间隔字段中的所有位设置为0。
The values of the above fields are usually provided by a measurement method, tool, or algorithm. This measurement algorithm is outside the scope of this specification.
上述字段的值通常由测量方法、工具或算法提供。此测量算法不在本规范的范围内。
The TWAMP Session-Reflector follows the procedures and guidelines in Section 4.2 of [RFC5357], with some changes and additional functions.
TWAMP会话反射器遵循[RFC5357]第4.2节中的程序和指南，并进行了一些更改和附加功能。
When the Value-Added Octets Version 1 feature is selected, the behavior of the Session-Reflector SHALL be as follows:
选择增值八位字节版本1功能时，会话反射器的行为应如下所示：
o The Session-Reflector MUST read the Version field. If Ver = 1, the Session-Reflector MUST read the L and I flag bits.
o 会话反射器必须读取版本字段。如果Ver=1，会话反射器必须读取L和I标志位。
o If L=1 and I=1, the Session-Reflector MUST read and extract the information from the Last Seqno in Train field and the Desired Reverse Packet Interval field in the value-added padding octets.
o 如果L=1和I=1，会话反射器必须读取并提取增值填充八位字节中最后一个序列号字段和所需反向数据包间隔字段中的信息。
- The Last Seqno in Train MUST be compared to Sequence Number in the same packet in order to determine when a complete train has been collected. The Session-Reflector SHOULD buffer the packets belonging to the current train (or store the packet-level performance data). After the last packet of the train has been received, the Session-Reflector SHOULD transmit the packets belonging to a reverse train with a waiting time (packet interval) for each packet indicated in the Desired Reverse Packet Interval field. If the Desired Reverse Packet Interval field is set to zero, then the Session-Reflector SHOULD transmit the packet as quickly as possible. The last packet within a train has Sender Sequence Number = Last Seqno in Train.
- 必须将序列中的最后一个序列号与同一数据包中的序列号进行比较，以确定何时收集了完整的序列。会话反射器应缓冲属于当前序列的数据包（或存储数据包级性能数据）。在已经接收到列车的最后一个分组之后，会话反射器应当发送属于反向列车的分组，并且在期望反向分组间隔字段中指示每个分组的等待时间（分组间隔）。如果期望的反向分组间隔字段设置为零，则会话反射器应尽快发送分组。列车内的最后一个数据包的发送方序列号=列车内的最后一个序列号。
- The Last Seqno in Train of a packet MUST also be compared to the Last Seqno in Train of the previous packet in order to determine if a new train needs to be collected. In case of packet loss, the Session-Reflector MUST transmit the incomplete train when it receives a packet with a Last Seqno in Train belonging to another train (e.g., next train) of the test session or after a timeout. The timeout MAY be the REFWAIT timer specified in section 4.2 of [RFC5357].
- 还必须将数据包序列中的最后一个序列号与前一个数据包序列中的最后一个序列号进行比较，以确定是否需要收集新序列。在数据包丢失的情况下，会话反射器必须在接收到属于测试会话的另一个序列（例如，下一个序列）的序列中最后一个序列号的数据包时或在超时后发送未完成序列。超时可能是[RFC5357]第4.2节中规定的REFWAIT定时器。
- Packets arriving out-of-order within a train MUST be buffered at the Session-Reflector if the train is not yet transmitted to the Session-Sender. If the train is already transmitted, the test packet SHOULD be returned to the Session-Sender as quickly as possible. The Session-Reflector MUST NOT reorder the test packets if they happen to arrive out-of-sequence.
- 如果列车尚未发送至会话发送方，则列车内无序到达的数据包必须在会话反射器处缓冲。如果列车已经传输，测试数据包应尽快返回给会话发送方。会话反射器不得对测试数据包重新排序，如果测试数据包的到达顺序不正确。
- Duplicate packets within a train MUST be buffered at the Session-Reflector if the train is not yet transmitted to the Session-Sender. If the train is already transmitted, the
- 如果列车尚未发送给会话发送方，则必须在会话反射器处缓冲列车内的重复数据包。如果列车已经传输，则
duplicate test packet SHOULD be returned to the Session-Sender as quickly as possible. The Session-Reflector MUST NOT discard duplicate test packets.
应尽快将重复的测试数据包返回给会话发送方。会话反射器不得丢弃重复的测试数据包。
For any other combinations of the Version field and the L and I flags, the Session-Reflector SHOULD return the test packet to the Session-Sender as quickly as possible.
对于版本字段和L和I标志的任何其他组合，会话反射器应尽快将测试数据包返回给会话发送器。
The Session-Reflector MUST implement the changes described above when the Value-Added Octets Version 1 feature is selected.
当选择增值八位字节版本1功能时，会话反射器必须实现上述更改。
The Session-Reflector packet format follows the same procedure and guidelines as defined in TWAMP [RFC5357] and TWAMP Reflect Octets and Symmetrical Size Features [RFC6038], with the following changes:
会话反射器数据包格式遵循TWAMP[RFC5357]和TWAMP反射八位字节和对称大小特征[RFC6038]中定义的相同程序和准则，但有以下更改：
o The Session-Reflector MUST reuse (reflect) the value-added padding octets (10 octets) provided in the Sender's Packet Padding.
o 会话反射器必须重用（反映）发送方数据包填充中提供的增值填充八位组（10个八位组）。
o The Session-Reflector MAY reuse the rest of the padding octets in the Sender's Packet Padding.
o 会话反射器可以重用发送方的分组填充中剩余的填充八位组。
The truncation process [RFC5357] is recommended when the Symmetrical mode is not used. The Session-Reflector MUST truncate exactly 27 octets of padding in Unauthenticated mode and exactly 56 octets in Authenticated and Encrypted modes.
当不使用对称模式时，建议使用截断过程[RFC5357]。会话反射器必须在未经身份验证的模式下精确截断27个八位字节的填充，在经过身份验证和加密的模式下精确截断56个八位字节。
The Session-Reflector supporting the Value-Added Octets feature should revert back to the standard Session-Reflector behavior if it cannot interpret the value-added padding octets in a given test packet. Section 5.2 also describes such behavior. For instance, the test packet is returned as quickly as possible to the Session-Sender when the Last Seqno in the Train is not what is expected.
如果会话反射器无法解释给定测试数据包中的增值填充八位字节，则支持增值八位字节功能的会话反射器应恢复为标准会话反射器行为。第5.2节也描述了此类行为。例如，当列车中的最后一个Seqno不是预期值时，测试数据包会尽快返回给会话发送方。
Capacity measurements introduce an additional consideration when the test sessions operate in TWAMP Light. When the Session-Reflector does not have knowledge of the session state, the measurement system may be restricted to estimating or calculating the capacity metrics in the forward path direction of transmission only. Capacity measurements in the reverse path direction is best handled with a Session-Reflector supporting knowledge of the session state and being capable of identifying the test packets belonging to a specific test session. A method for creating a session state from the initial test packet may be implemented on the TWAMP Light Session-Reflector. This is outside the scope of this specification.
当测试会话在TWAMP灯光下运行时，容量测量引入了额外的考虑因素。当会话反射器不知道会话状态时，测量系统可仅限于估计或计算传输的前向路径方向上的容量度量。反向路径方向上的容量测量最好使用支持会话状态知识并能够识别属于特定测试会话的测试分组的会话反射器来处理。可以在TWAMP光会话反射器上实现用于从初始测试分组创建会话状态的方法。这超出了本规范的范围。
This memo describes the protocol used in the current working prototype implementation of the Value-Added Octets feature in the Ericsson lab. The prototype has been tested in real network environments. The conclusion from these tests is that the Value-Added Octets feature is able to enable estimation of capacity metrics such as available path capacity in both the forward and reverse directions of the network path.
本备忘录描述了爱立信实验室增值八位字节功能的当前工作原型实现中使用的协议。该原型已在实际网络环境中进行了测试。这些测试得出的结论是，增值八位字节功能能够估计容量指标，如网络路径正向和反向的可用路径容量。
During the experiments with the protocol described in this memo, we have identified a need for the controller and responder to use the same maximum train length. The reflector must be able to buffer the whole train received from the controller. In order to reduce the risk for buffer overrun, the maximum train length should be negotiated. This can be resolved through configuration, introduction of a new field in the value-added octets, or a new maximum train length field in the Request-TW-Session message.
在本备忘录所述协议的实验过程中，我们发现控制器和响应器需要使用相同的最大列车长度。反射器必须能够缓冲从控制器接收到的整个列车。为了降低缓冲区超限的风险，应协商最大列车长度。这可以通过配置、在增值八位字节中引入新字段或在请求TW会话消息中引入新的最大列车长度字段来解决。
The Sender Discriminator (SD) field, which was proposed in an early draft of this document, was removed because of complications with different Session-Reflector implementations. A Session-Reflector may not be able to easily identify the SD field or associate it with a specific Session-Sender, which may skew the test results.
在本文档的早期草稿中提出的发送方鉴别器（SD）字段由于不同会话反射器实现的复杂性而被删除。会话反射器可能无法轻松识别SD字段或将其与特定会话发送者关联，这可能会扭曲测试结果。
The flags defined in the value-added octets now indicate the usage of fields and not the presence of fields. This modification was needed to simplify the responder implementation in the working prototype.
增值八位字节中定义的标志现在表示字段的使用，而不是字段的存在。为了简化工作原型中的响应器实现，需要进行此修改。
The value-added padding octets permit DoS attacks on the responder host communicating with core TWAMP [RFC5357]. For instance, a DoS condition could arise when the Last Seqno in Train is too large to handle, potentially causing undesirable processing delay or discard of the TWAMP-Test packets. The responder host MUST provide a mechanism to protect or limit the use of its local memory, buffer space, or maximum transmission time for a train.
增值的填充八位组允许对与核心TWAMP[RFC5357]通信的响应主机进行DoS攻击。例如，当序列中的最后一个Seqno太大而无法处理时，可能会出现DoS情况，这可能会导致不良的处理延迟或丢弃TWAMP测试数据包。响应主机必须提供一种机制来保护或限制列车本地内存、缓冲空间或最大传输时间的使用。
The security considerations that apply to any active measurement of live networks are relevant here as well. See [RFC4656] and [RFC5357].
适用于实时网络的任何主动测量的安全注意事项也与此相关。参见[RFC4656]和[RFC5357]。
The authors thank Svante Ekelin for providing direction and comments on this document.
作者感谢Svante Ekelin为本文件提供指导和意见。
[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。
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. Zekauskas, "A One-way Active Measurement Protocol (OWAMP)", RFC 4656, September 2006.
[RFC4656]Shalunov，S.，Teitelbaum，B.，Karp，A.，Boote，J.，和M.Zekauskas，“单向主动测量协议（OWAMP）”，RFC 46562006年9月。
[RFC5136] Chimento, P. and J. Ishac, "Defining Network Capacity", RFC 5136, February 2008.
[RFC5136]Chimento，P.和J.Ishac，“定义网络容量”，RFC 5136，2008年2月。
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, October 2008.
[RFC5357]Hedayat，K.，Krzanowski，R.，Morton，A.，Yum，K.，和J.Babiarz，“双向主动测量协议（TWAMP）”，RFC 5357，2008年10月。
[RFC6038] Morton, A. and L. Ciavattone, "Two-Way Active Measurement Protocol (TWAMP) Reflect Octets and Symmetrical Size Features", RFC 6038, October 2010.
[RFC6038]Morton，A.和L.Ciavattone，“双向主动测量协议（TWAMP）反映八位组和对称尺寸特征”，RFC 6038，2010年10月。
[ENHJMMB] Ekelin, S., Nilsson, M., Hartikainen, E., Johnsson, A., Mangs, J., Melander, B., and M. Bjorkman, "Real-Time Measurement of End-to-End Available Bandwidth Using Kalman Filtering", Proceedings to the IEEE/IFIP Network Operations and Management Symposium, 2006.
[ENHJMMB]Ekelin，S.，Nilsson，M.，Hartikainen，E.，Johnsson，A.，Mangs，J.，Melander，B.，和M.Bjorkman，“使用卡尔曼滤波实时测量端到端可用带宽”，IEEE/IFIP网络运营和管理研讨会论文集，2006年。
[PDM] Dovrolis, C., Ramanathan, P., and D. Moore, "Packet-Dispersion Techniques and a Capacity-Estimation Methodology", IEEE/ACM Transactions on Networking, December 2004.
[PDM]Dovrolis，C.，Ramanathan，P.，和D.Moore，“数据包分散技术和容量估计方法”，IEEE/ACM网络事务，2004年12月。
[RRBNC] Ribeiro, V., Riedi, R., Baraniuk, R., Navratil, J., and L. Cottrel, "pathChirp: Efficient Available Bandwidth Estimation for Network Paths", Passive and Active Monitoring Workshop, 2003.
[RRBNC]Ribeiro，V.，Riedi，R.，Baraniuk，R.，Navratil，J.，和L.Cottrel，“路径啁啾：网络路径的有效可用带宽估计”，被动和主动监测研讨会，2003年。
[SBW] Sommers, J., Barford, P., and W. Willinger, "Laboratory-based Calibration of Available Bandwidth Estimation Tools", Microprocessors and Microsystems, 2007.
[SBW]Sommers，J.，Barford，P.，和W.Willinger，“可用带宽估计工具的实验室校准”，微处理器和微系统，2007年。
[Y1540] International Telecommunications Union, "Internet protocol data communication service - IP packet transfer and availability performance parameters", ITU-T Recommendation Y.1540, 2011.
[Y1540]国际电信联盟，“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”，ITU-T建议Y.1540，2011年。
Authors' Addresses
作者地址
Steve Baillargeon Ericsson 3500 Carling Avenue Ottawa, Ontario K2H 8E9 Canada
Steve Baillargeon Ericsson加拿大安大略省渥太华卡林大道3500号K2H 8E9
EMail: steve.baillargeon@ericsson.com
EMail: steve.baillargeon@ericsson.com
Christofer Flinta Ericsson Farogatan 6 Stockholm, 164 80 Sweden
Christofer Flinta Ericsson Farogatan 6斯德哥尔摩16480瑞典
EMail: christofer.flinta@ericsson.com
EMail: christofer.flinta@ericsson.com
Andreas Johnsson Ericsson Farogatan 6 Stockholm, 164 80 Sweden
Andreas Johnsson Ericsson Farogatan 6斯德哥尔摩16480瑞典
EMail: andreas.a.johnsson@ericsson.com
EMail: andreas.a.johnsson@ericsson.com