Internet Engineering Task Force (IETF) L. Ginsberg, Ed.
Request for Comments: 8570 Cisco Systems, Inc.
Obsoletes: 7810 S. Previdi, Ed.
Category: Standards Track Huawei
ISSN: 2070-1721 S. Giacalone
Microsoft
D. Ward
Cisco Systems, Inc.
J. Drake
Juniper Networks
Q. Wu
Huawei
March 2019
Internet Engineering Task Force (IETF) L. Ginsberg, Ed.
Request for Comments: 8570 Cisco Systems, Inc.
Obsoletes: 7810 S. Previdi, Ed.
Category: Standards Track Huawei
ISSN: 2070-1721 S. Giacalone
Microsoft
D. Ward
Cisco Systems, Inc.
J. Drake
Juniper Networks
Q. Wu
Huawei
March 2019
IS-IS Traffic Engineering (TE) Metric Extensions
IS-IS流量工程（TE）度量扩展
Abstract
摘要
In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network-performance criteria (e.g., latency) are becoming as critical to data-path selection as other metrics.
在某些网络中，例如但不限于金融信息网络（例如股票市场数据提供商），网络性能标准（例如延迟）对于数据路径选择的重要性与其他指标一样。
This document describes extensions to IS-IS Traffic Engineering Extensions (RFC 5305). These extensions provide a way to distribute and collect network-performance information in a scalable fashion. The information distributed using IS-IS TE Metric Extensions can then be used to make path-selection decisions based on network performance.
本文档描述IS-IS流量工程扩展（RFC 5305）的扩展。这些扩展提供了一种以可扩展方式分发和收集网络性能信息的方法。使用IS-IS TE度量扩展分发的信息可用于根据网络性能做出路径选择决策。
Note that this document only covers the mechanisms with which network-performance information is distributed. The mechanisms for measuring network performance or acting on that information, once distributed, are outside the scope of this document.
请注意，本文档仅介绍分发网络性能信息的机制。测量网络性能或对该信息采取行动的机制，一旦分发，不在本文件的范围之内。
This document obsoletes RFC 7810.
本文件淘汰了RFC 7810。
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 https://www.rfc-editor.org/info/rfc8570.
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https://www.rfc-editor.org/info/rfc8570.
Copyright Notice
版权公告
Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.
版权（c）2019 IETF信托基金和被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 (https://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(https://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. Requirements Language ......................................4
2. TE Metric Extensions to IS-IS ...................................5
3. Interface and Neighbor Addresses ................................6
4. Sub-TLV Details .................................................7
4.1. Unidirectional Link Delay Sub-TLV ..........................7
4.2. Min/Max Unidirectional Link Delay Sub-TLV ..................8
4.3. Unidirectional Delay Variation Sub-TLV .....................9
4.4. Unidirectional Link Loss Sub-TLV ..........................10
4.5. Unidirectional Residual Bandwidth Sub-TLV .................11
4.6. Unidirectional Available Bandwidth Sub-TLV ................12
4.7. Unidirectional Utilized Bandwidth Sub-TLV .................13
5. Announcement Thresholds and Filters ............................13
6. Announcement Suppression .......................................14
7. Network Stability and Announcement Periodicity .................15
8. Enabling and Disabling Sub-TLVs ................................15
9. Static Metric Override .........................................15
10. Compatibility .................................................15
11. Security Considerations .......................................15
12. IANA Considerations ...........................................16
13. References ....................................................17
13.1. Normative References .....................................17
13.2. Informative References ...................................18
Appendix A. Changes from RFC 7810 .................................19
Acknowledgements ..................................................20
Contributors ......................................................20
Authors' Addresses ................................................21
1. Introduction ....................................................3
1.1. Requirements Language ......................................4
2. TE Metric Extensions to IS-IS ...................................5
3. Interface and Neighbor Addresses ................................6
4. Sub-TLV Details .................................................7
4.1. Unidirectional Link Delay Sub-TLV ..........................7
4.2. Min/Max Unidirectional Link Delay Sub-TLV ..................8
4.3. Unidirectional Delay Variation Sub-TLV .....................9
4.4. Unidirectional Link Loss Sub-TLV ..........................10
4.5. Unidirectional Residual Bandwidth Sub-TLV .................11
4.6. Unidirectional Available Bandwidth Sub-TLV ................12
4.7. Unidirectional Utilized Bandwidth Sub-TLV .................13
5. Announcement Thresholds and Filters ............................13
6. Announcement Suppression .......................................14
7. Network Stability and Announcement Periodicity .................15
8. Enabling and Disabling Sub-TLVs ................................15
9. Static Metric Override .........................................15
10. Compatibility .................................................15
11. Security Considerations .......................................15
12. IANA Considerations ...........................................16
13. References ....................................................17
13.1. Normative References .....................................17
13.2. Informative References ...................................18
Appendix A. Changes from RFC 7810 .................................19
Acknowledgements ..................................................20
Contributors ......................................................20
Authors' Addresses ................................................21
In certain networks, such as, but not limited to, financial information networks (e.g., stock market data providers), network-performance information (e.g., latency) is becoming as critical to data-path selection as other metrics.
在某些网络中，例如但不限于金融信息网络（例如，股票市场数据提供商），网络性能信息（例如，延迟）与其他指标一样，对数据路径选择至关重要。
In these networks, extremely large amounts of money rest on the ability to access market data in "real time" and to predictably make trades faster than the competition. Because of this, using metrics such as hop count or cost as routing metrics is becoming only tangentially important. Rather, it would be beneficial to be able to make path-selection decisions based on performance data (such as latency) in a cost-effective and scalable way.
在这些网络中，大量资金依赖于“实时”访问市场数据的能力，以及可以预见的交易速度快于竞争对手的能力。因此，使用跃点计数或成本等指标作为路由指标变得非常重要。相反，能够以经济高效且可扩展的方式基于性能数据（如延迟）做出路径选择决策将是有益的。
This document describes extensions (hereafter called "IS-IS TE Metric Extensions") to the Extended IS Reachability TLV defined in [RFC5305]; these extensions can be used to distribute network-performance information (such as link delay, delay variation, packet loss, residual bandwidth, and available bandwidth).
本文件描述了[RFC5305]中定义的扩展IS可达性TLV的扩展（以下称为“IS-IS TE度量扩展”）；这些扩展可用于分发网络性能信息（例如链路延迟、延迟变化、数据包丢失、剩余带宽和可用带宽）。
The data distributed by the IS-IS TE Metric Extensions described in this document is meant to be used as part of the operation of the routing protocol (e.g., by replacing cost with latency or considering bandwidth as well as cost), to enhance Constrained Shortest Path First (CSPF), or for other uses such as supplementing the data used by an Application-Layer Traffic Optimization (ALTO) server [RFC7285]. With respect to CSPF, the data distributed by IS-IS TE Metric Extensions can be used to set up, fail over, and fail back data paths using protocols such as RSVP-TE [RFC3209].
本文件中描述的IS-IS TE度量扩展所分发的数据旨在用作路由协议操作的一部分（例如，用延迟替换成本或考虑带宽和成本），以增强受限最短路径优先（CSPF），或用于其他用途，如补充应用层流量优化（ALTO）服务器使用的数据[RFC7285]。关于CSPF，IS-IS TE度量扩展分发的数据可用于使用诸如RSVP-TE[RFC3209]等协议建立、故障转移和故障回复数据路径。
Note that the mechanisms described in this document only disseminate performance information. The methods for initially gathering that performance information (such as the methods described in [RFC6375]) or how to act on the information once it is distributed are outside the scope of this document. Example mechanisms to measure latency, delay variation, and loss in an MPLS network are given in [RFC6374]. While this document does not specify how the performance information should be obtained, the measurement of delay SHOULD NOT vary significantly based upon the offered traffic load. Thus, queuing delays SHOULD NOT be included in the delay measurement. For links such as forwarding adjacencies [RFC4206], care must be taken that measurement of the associated delay avoids significant queuing delays; that could be accomplished in a variety of ways, including either (1) measuring with a traffic class that experiences minimal queuing or (2) summing the measured link delays of the components of the link's path.
请注意，本文档中描述的机制仅传播性能信息。最初收集该性能信息的方法（如[RFC6375]中描述的方法）或在信息发布后如何对其采取行动不在本文件的范围内。[RFC6374]中给出了测量MPLS网络中的延迟、延迟变化和丢失的示例机制。虽然本文件未规定应如何获得性能信息，但延迟的测量值不应根据提供的交通负荷发生显著变化。因此，延迟测量中不应包括排队延迟。对于诸如转发邻接[RFC4206]之类的链路，必须注意相关延迟的测量避免显著的排队延迟；这可以通过多种方式实现，包括（1）使用经历最小排队的流量类别进行测量，或（2）将测量的链路路径组件的链路延迟相加。
This document obsoletes [RFC7810].
本文件废除了[RFC7810]。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
This document registers new IS-IS TE sub-TLVs in the "Sub-TLVs for TLVs 22, 23, 141, 222, and 223" registry. These new sub-TLVs provide ways to distribute network-performance information. The extensions in this document build on the extensions provided in IS-IS TE [RFC5305] and GMPLS [RFC4203].
本文件将新IS-IS TE子TLV登记在“TLV 22、23、141、222和223子TLV”登记册中。这些新的子TLV提供了分发网络性能信息的方法。本文档中的扩展基于IS-IS TE[RFC5305]和GMPLS[RFC4203]中提供的扩展。
The Extended IS Reachability TLV (type 22) (defined in [RFC5305]), Inter-AS Reachability TLV (also called "inter-AS reachability information TLV") (type 141) (defined in [RFC5316]), and MT-ISN TLV (type 222) (defined in [RFC5120]) have nested sub-TLVs that permit the TLVs to be readily extended. This document registers several sub-TLVs:
扩展IS可达性TLV（类型22）（在[RFC5305]中定义）、内部AS可达性TLV（也称为“内部AS可达性信息TLV”）（类型141）（在[RFC5316]中定义）和MT-ISN TLV（类型222）（在[RFC5120]中定义）具有允许TLV容易扩展的嵌套子TLV。本文件登记了多个子TLV：
Type Description
----------------------------------------------------
33 Unidirectional Link Delay
Type Description
----------------------------------------------------
33 Unidirectional Link Delay
34 Min/Max Unidirectional Link Delay
34最小/最大单向链路延迟
35 Unidirectional Delay Variation
35单向延迟变化
36 Unidirectional Link Loss
36单向链路损耗
37 Unidirectional Residual Bandwidth
37单向剩余带宽
38 Unidirectional Available Bandwidth
38单向可用带宽
39 Unidirectional Utilized Bandwidth
39单向利用带宽
As can be seen in the list above, the sub-TLVs described in this document carry different types of network-performance information. The new sub-TLVs include a bit called the Anomalous (or "A") bit. When the A bit is clear (or when the sub-TLV does not include an A bit), the sub-TLV describes steady-state link performance. This information could conceivably be used to construct a steady-state performance topology for initial tunnel-path computation or to verify alternative failover paths.
从上面的列表中可以看出，本文档中描述的子TLV携带不同类型的网络性能信息。新的子TLV包括一个称为异常（或“a”）位的位。当A位清除时（或当子TLV不包括A位时），子TLV描述稳态链路性能。可以想象，该信息可用于构建用于初始隧道路径计算的稳态性能拓扑，或用于验证替代故障切换路径。
When network performance violates configurable link-local thresholds, a sub-TLV with the A bit set is advertised. That sub-TLV could be used by the receiving node to determine whether to (1) fail traffic to a backup path or (2) calculate an entirely new path. From an MPLS perspective, the intent of the A bit is to permit label switched path ingress nodes to determine whether the link referenced in the sub-TLV affects any of the label switched paths for which it is ingress. If
当网络性能违反可配置的链路本地阈值时，将公布具有位集的子TLV。接收节点可以使用该子TLV来确定是（1）使通信失败到备份路径，还是（2）计算一个全新的路径。从MPLS的角度来看，比特的目的是允许标签交换路径入口节点确定子TLV中引用的链路是否影响其所进入的任何标签交换路径。如果
they are affected, then they can determine whether those label switched paths still meet end-to-end performance objectives. If not, then the node could conceivably move affected traffic to a pre-established protection label switched path or establish a new label switched path and place the traffic in it.
它们会受到影响，然后可以确定这些标签交换路径是否仍然满足端到端性能目标。如果不是，则节点可以想象地将受影响的业务移动到预先建立的保护标签交换路径，或者建立新的标签交换路径并将业务置于其中。
If link performance then improves beyond a configurable minimum value (reuse threshold), that sub-TLV can be re-advertised with the A bit cleared. In this case, a receiving node can conceivably do whatever re-optimization (or failback) it wishes to do (including nothing).
若链路性能改善超过了可配置的最小值（重用阈值），那个么子TLV可以在清除位的情况下重新发布。在这种情况下，可以想象接收节点可以执行其希望执行的任何重新优化（或故障回复）（不包括任何操作）。
Note that when a sub-TLV does not include the A bit, that sub-TLV cannot be used for failover purposes. The A bit was intentionally omitted from some sub-TLVs to help mitigate oscillations. See Section 5 for more information.
请注意，当子TLV不包括a位时，该子TLV不能用于故障切换目的。一些子TLV故意省略了A位，以帮助缓解振荡。更多信息请参见第5节。
Consistent with the existing IS-IS TE specification [RFC5305], the bandwidth advertisements defined in this document MUST be encoded as IEEE floating-point values [IEEE754]. The delay and delay-variation advertisements defined in this document MUST be encoded as integer values. Delay values MUST be quantified in units of microseconds, packet loss MUST be quantified as a percentage of packets sent, and bandwidth MUST be sent as bytes per second. All values (except residual bandwidth) MUST be calculated as rolling averages, where the averaging period MUST be a configurable period of time. See Section 5 for more information.
与现有IS-IS TE规范[RFC5305]一致，本文件中定义的带宽广告必须编码为IEEE浮点值[IEEE754]。本文件中定义的延迟和延迟变化广告必须编码为整数值。延迟值必须以微秒为单位进行量化，数据包丢失必须以发送数据包的百分比进行量化，带宽必须以每秒字节数的形式发送。所有值（剩余带宽除外）必须计算为滚动平均值，其中平均周期必须是可配置的时间段。更多信息请参见第5节。
The use of IS-IS TE Metric Extensions sub-TLVs is not confined to the TE context. In other words, IS-IS TE Metric Extensions sub-TLVs defined in this document can also be used for computing paths in the absence of a TE subsystem.
IS-IS TE度量扩展子TLV的使用不限于TE上下文。换句话说，本文档中定义的IS-IS TE度量扩展子TLV也可用于在没有TE子系统的情况下计算路径。
However, as for the TE case, Interface Address and Neighbor Address sub-TLVs (IPv4 or IPv6) MUST be present. The encoding is defined in [RFC5305] for IPv4 and in [RFC6119] for IPv6.
但是，对于TE情况，接口地址和邻居地址子TLV（IPv4或IPv6）必须存在。编码在[RFC5305]中针对IPv4定义，在[RFC6119]中针对IPv6定义。
This sub-TLV advertises the average link delay between two directly connected IS-IS neighbors. The delay advertised by this sub-TLV MUST be the delay from the local neighbor to the remote neighbor (i.e., the forward-path latency). The format of this sub-TLV is shown in the following diagram:
此子TLV播发两个直接连接的IS-IS邻居之间的平均链路延迟。此子TLV公布的延迟必须是从本地邻居到远程邻居的延迟（即，前向路径延迟）。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
图1
where:
哪里：
Type: 33
类型：33
Length: 4
长度：4
A bit: This field represents the Anomalous (A) bit. The A bit is set when the measured value of this parameter exceeds its configured maximum threshold. The A bit is cleared when the measured value falls below its configured reuse threshold. If the A bit is cleared, the sub-TLV represents steady-state link performance.
A位：此字段表示异常（A）位。当此参数的测量值超过其配置的最大阈值时，将设置A位。当测量值低于其配置的重用阈值时，A位被清除。如果A位被清除，则子TLV表示稳态链路性能。
RESERVED: This field is reserved for future use. It MUST be set to 0 when sent and MUST be ignored when received.
保留：此字段保留供将来使用。发送时必须将其设置为0，接收时必须忽略。
Delay: This 24-bit field carries the average link delay over a configurable interval in microseconds, encoded as an integer value. When set to the maximum value 16,777,215 (16.777215 seconds), then the delay is at least that value and may be larger.
延迟：此24位字段以微秒为单位携带可配置间隔内的平均链路延迟，编码为整数值。当设置为最大值16777215（16.777215秒）时，延迟至少为该值且可能更大。
This sub-TLV advertises the minimum and maximum delay values between two directly connected IS-IS neighbors. The delay advertised by this sub-TLV MUST be the delay from the local neighbor to the remote neighbor (i.e., the forward-path latency). The format of this sub-TLV is shown in the following diagram:
此子TLV播发两个直接连接的IS-IS邻居之间的最小和最大延迟值。此子TLV公布的延迟必须是从本地邻居到远程邻居的延迟（即，前向路径延迟）。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Min Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Max Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Min Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Max Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
图2
where:
哪里：
Type: 34
类型：34
Length: 8
长度：8
A bit: This field represents the Anomalous (A) bit. The A bit is set when one or more measured values exceed a configured maximum threshold. The A bit is cleared when the measured value falls below its configured reuse threshold. If the A bit is cleared, the sub-TLV represents steady-state link performance.
A位：此字段表示异常（A）位。当一个或多个测量值超过配置的最大阈值时，设置A位。当测量值低于其配置的重用阈值时，A位被清除。如果A位被清除，则子TLV表示稳态链路性能。
RESERVED: This field is reserved for future use. It MUST be set to 0 when sent and MUST be ignored when received.
保留：此字段保留供将来使用。发送时必须将其设置为0，接收时必须忽略。
Min Delay: This 24-bit field carries the minimum measured link delay value (in microseconds) over a configurable interval, encoded as an integer value.
Min Delay（最小延迟）：该24位字段在可配置的时间间隔内携带最小测量链路延迟值（以微秒为单位），编码为整数值。
Max Delay: This 24-bit field carries the maximum measured link delay value (in microseconds) over a configurable interval, encoded as an integer value.
最大延迟：此24位字段在可配置的时间间隔内携带最大测量链路延迟值（以微秒为单位），编码为整数值。
Implementations MAY also permit the configuration of an offset value (in microseconds) to be added to the measured delay value, to facilitate the communication of operator-specific delay constraints.
实现还可以允许将偏移值（以微秒为单位）的配置添加到测量的延迟值，以促进特定于操作员的延迟约束的通信。
It is possible for Min Delay and Max Delay to be the same value.
最小延迟和最大延迟可能是相同的值。
When the delay value (Min Delay or Max Delay) is set to the maximum value 16,777,215 (16.777215 seconds), then the delay is at least that value and may be larger.
当延迟值（最小延迟或最大延迟）设置为最大值16777215（16.777215秒）时，延迟至少为该值且可能更大。
This sub-TLV advertises the average link delay variation between two directly connected IS-IS neighbors. The delay variation advertised by this sub-TLV MUST be the delay from the local neighbor to the remote neighbor (i.e., the forward-path latency). The format of this sub-TLV is shown in the following diagram:
该子TLV播发两个直接连接的IS-IS邻居之间的平均链路延迟变化。此子TLV公布的延迟变化必须是从本地邻居到远程邻居的延迟（即，前向路径延迟）。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Delay Variation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Delay Variation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
图3
where:
哪里：
Type: 35
类型：35
Length: 4
长度：4
RESERVED: This field is reserved for future use. It MUST be set to 0 when sent and MUST be ignored when received.
保留：此字段保留供将来使用。发送时必须将其设置为0，接收时必须忽略。
Delay Variation: This 24-bit field carries the average link delay variation over a configurable interval in microseconds, encoded as an integer value. When set to 0, it has not been measured. When set to the maximum value 16,777,215 (16.777215 seconds), then the delay is at least that value and may be larger.
延迟变化：该24位字段以微秒为单位携带可配置间隔内的平均链路延迟变化，编码为整数值。设置为0时，未对其进行测量。当设置为最大值16777215（16.777215秒）时，延迟至少为该值且可能更大。
This sub-TLV advertises the loss (as a packet percentage) between two directly connected IS-IS neighbors. The link loss advertised by this sub-TLV MUST be the packet loss from the local neighbor to the remote neighbor (i.e., the forward-path loss). The format of this sub-TLV is shown in the following diagram:
此子TLV播发两个直接连接的IS-IS邻居之间的丢失（以数据包百分比表示）。此子TLV公布的链路丢失必须是从本地邻居到远程邻居的数据包丢失（即，前向路径丢失）。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Link Loss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Link Loss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4
图4
where:
哪里：
Type: 36
类型：36
Length: 4
长度：4
A bit: This field represents the Anomalous (A) bit. The A bit is set when the measured value of this parameter exceeds its configured maximum threshold. The A bit is cleared when the measured value falls below its configured reuse threshold. If the A bit is cleared, the sub-TLV represents steady-state link performance.
A位：此字段表示异常（A）位。当此参数的测量值超过其配置的最大阈值时，将设置A位。当测量值低于其配置的重用阈值时，A位被清除。如果A位被清除，则子TLV表示稳态链路性能。
RESERVED: This field is reserved for future use. It MUST be set to 0 when sent and MUST be ignored when received.
保留：此字段保留供将来使用。发送时必须将其设置为0，接收时必须忽略。
Link Loss: This 24-bit field carries link packet loss as a percentage of the total traffic sent over a configurable interval. The basic unit is 0.000003%, where (2^24 - 2) is 50.331642%. This value is the highest packet-loss percentage that can be expressed (the assumptions being that (1) precision is more important on high-speed links than the ability to advertise loss rates greater than this and (2) high-speed links with over 50% loss are unusable). Therefore, measured values that are larger than the field maximum SHOULD be encoded as the maximum value.
链路丢失：此24位字段以在可配置间隔内发送的总通信量的百分比表示链路数据包丢失。基本单位为0.000003%，其中（2^24-2）为50.331642%。该值是可以表示的最高数据包丢失百分比（假设：（1）在高速链路上，精度比公布大于该值的丢失率的能力更重要；（2）丢失率超过50%的高速链路不可用）。因此，大于字段最大值的测量值应编码为最大值。
This sub-TLV advertises the residual bandwidth between two directly connected IS-IS neighbors. The residual bandwidth advertised by this sub-TLV MUST be the residual bandwidth from the system originating the Link State Advertisement (LSA) to its neighbor.
该子TLV播发两个直接连接的IS-IS邻居之间的剩余带宽。此子TLV播发的剩余带宽必须是从发起链路状态播发（LSA）的系统到其邻居的剩余带宽。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Residual Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Residual Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5
图5
where:
哪里：
Type: 37
类型：37
Length: 4
长度：4
Residual Bandwidth: This field carries the residual bandwidth on a link, forwarding adjacency [RFC4206], or bundled link in IEEE floating-point format with units of bytes per second. For a link or forwarding adjacency, residual bandwidth is defined to be the maximum bandwidth [RFC5305] minus the bandwidth currently allocated to RSVP-TE label switched paths. For a bundled link, residual bandwidth is defined to be the sum of the component link residual bandwidths.
剩余带宽：该字段携带链路、转发邻接[RFC4206]或IEEE浮点格式捆绑链路上的剩余带宽，单位为字节/秒。对于链路或转发邻接，剩余带宽定义为最大带宽[RFC5305]减去当前分配给RSVP-TE标签交换路径的带宽。对于捆绑链路，剩余带宽定义为组件链路剩余带宽之和。
The calculation of residual bandwidth is different than that of unreserved bandwidth [RFC5305]. This calculation subtracts tunnel reservations from maximum bandwidth (i.e., the link capacity) [RFC5305] and provides an aggregated remainder across priorities. Unreserved bandwidth, on the other hand, is subtracted from the maximum reservable bandwidth (the bandwidth that can theoretically be reserved) and provides per-priority remainders. Residual bandwidth and unreserved bandwidth [RFC5305] can be used concurrently, and each has a separate use case (e.g., the former can be used for applications like Weighted ECMP, while the latter can be used for call admission control).
剩余带宽的计算不同于未保留带宽的计算[RFC5305]。此计算从最大带宽（即链路容量）中减去隧道预留量[RFC5305]，并提供跨优先级的聚合余数。另一方面，从最大可保留带宽（理论上可以保留的带宽）中减去未保留带宽，并提供每优先级剩余。剩余带宽和非保留带宽[RFC5305]可以同时使用，并且每个都有单独的用例（例如，前者可用于加权ECMP等应用，而后者可用于呼叫允许控制）。
This sub-TLV advertises the available bandwidth between two directly connected IS-IS neighbors. The available bandwidth advertised by this sub-TLV MUST be the available bandwidth from the system originating this sub-TLV. The format of this sub-TLV is shown in the following diagram:
此子TLV播发两个直接连接的IS-IS邻居之间的可用带宽。此子TLV公布的可用带宽必须是源自此子TLV的系统的可用带宽。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6
图6
where:
哪里：
Type: 38
类型：38
Length: 4
长度：4
Available Bandwidth: This field carries the available bandwidth on a link, forwarding adjacency, or bundled link in IEEE floating-point format with units of bytes per second. For a link or forwarding adjacency, available bandwidth is defined to be residual bandwidth (see Section 4.5) minus the measured bandwidth used for the actual forwarding of non-RSVP-TE label switched path packets. For a bundled link, available bandwidth is defined to be the sum of the component link available bandwidths.
可用带宽：此字段以IEEE浮点格式携带链路、转发邻接或捆绑链路上的可用带宽，单位为字节/秒。对于链路或转发邻接，可用带宽定义为剩余带宽（见第4.5节）减去用于实际转发非RSVP TE标签交换路径数据包的测量带宽。对于捆绑链路，可用带宽定义为组件链路可用带宽之和。
This sub-TLV advertises the bandwidth utilization between two directly connected IS-IS neighbors. The bandwidth utilization advertised by this sub-TLV MUST be the bandwidth from the system originating this sub-TLV. The format of this sub-TLV is shown in the following diagram:
该子TLV公布两个直接连接的IS-IS邻居之间的带宽利用率。此子TLV公布的带宽利用率必须是来自发起此子TLV的系统的带宽。该子TLV的格式如下图所示：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Utilized Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Utilized Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7
图7
where:
哪里：
Type: 39
类型：39
Length: 4
长度：4
Utilized Bandwidth: This field carries the bandwidth utilization on a link, forwarding adjacency, or bundled link in IEEE floating-point format with units of bytes per second. For a link or forwarding adjacency, bandwidth utilization represents the actual utilization of the link (i.e., as measured by the advertising node). For a bundled link, bandwidth utilization is defined to be the sum of the component link bandwidth utilizations.
已利用带宽：此字段以IEEE浮点格式携带链路、转发邻接或捆绑链路上的带宽利用率，单位为字节/秒。对于链路或转发邻接，带宽利用率表示链路的实际利用率（即，由广告节点测量）。对于捆绑链路，带宽利用率定义为组件链路带宽利用率之和。
The values advertised in all sub-TLVs (except minimum/maximum delay and residual bandwidth) MUST represent an average over a period of time or be obtained by a filter that is reasonably representative of an average. For example, a rolling average is one such filter.
在所有子TLV中公布的值（最小/最大延迟和剩余带宽除外）必须代表一段时间内的平均值，或由合理代表平均值的过滤器获得。例如，滚动平均值就是这样一个过滤器。
Minimum and maximum delay MUST each be derived in one of the following ways: by taking the lowest and/or highest measured value over a measurement interval or by making use of a filter or other technique to obtain a reasonable representation of a minimum value and a maximum value representative of the interval, with compensation for outliers.
最小和最大延迟必须分别通过以下方式之一得出：通过在测量间隔内获取最低和/或最高测量值，或通过使用过滤器或其他技术获得代表间隔的最小值和最大值的合理表示，并对异常值进行补偿。
The measurement interval, any filter coefficients, and any advertisement intervals MUST be configurable per sub-TLV.
测量间隔、任何滤波器系数和任何广告间隔必须可根据子TLV进行配置。
In addition to the measurement intervals governing re-advertisement, implementations SHOULD provide configurable accelerated advertisement thresholds per sub-TLV, such that:
除了管理重新发布的测量间隔外，实施还应为每个子TLV提供可配置的加速发布阈值，以便：
1. If the measured parameter falls outside a configured upper bound for all but the minimum delay metric (or lower bound for the minimum delay metric only) and the advertised sub-TLV is not already outside that bound, or
1. 如果测量参数超出了除最小延迟度量（或仅限最小延迟度量的下限）之外的所有配置上限，且公布的子TLV尚未超出该上限，或
2. If the difference between the last advertised value and current measured value exceeds a configured threshold, then
2. 如果最后公布的值和当前测量值之间的差值超过配置的阈值，则
3. The advertisement is made immediately.
3. 广告马上就做了。
4. For sub-TLVs that include an A bit, an additional threshold SHOULD be included corresponding to the threshold for which the performance is considered anomalous (and sub-TLVs with the A bit are sent). The A bit is cleared when the sub-TLV's performance has been below (or re-crosses) this threshold for one or more advertisement intervals to permit failback.
4. 对于包含A位的子TLV，应包含一个额外的阈值，该阈值对应于性能被视为异常的阈值（并发送带有A位的子TLV）。当子TLV的性能在一个或多个播发间隔内低于（或重新超过）该阈值时，A位被清除，以允许回切。
To prevent oscillations, only the high threshold or the low threshold (but not both) may be used to trigger any given sub-TLV that supports both.
为了防止振荡，只能使用高阈值或低阈值（但不能同时使用两者）来触发支持两者的任何给定子TLV。
Additionally, once outside the bounds of the threshold, any re-advertisement of a measurement within the bounds would remain governed solely by the measurement interval for that sub-TLV.
此外，一旦超出阈值边界，边界内测量的任何重新公布将仅由该子TLV的测量间隔控制。
When link-performance values change by small amounts that fall under thresholds that would cause the announcement of a sub-TLV, implementations SHOULD suppress sub-TLV re-advertisement and/or lengthen the period within which the sub-TLVs are refreshed.
当链路性能值的变化量很小，低于会导致宣布子TLV的阈值时，实施应抑制子TLV重新公布和/或延长子TLV刷新的周期。
Only the accelerated advertisement threshold mechanism described in Section 5 may shorten the re-advertisement interval. All suppression and re-advertisement interval backoff timer features SHOULD be configurable.
只有第5节中描述的加速广告阈值机制可以缩短重新广告间隔。所有抑制和重新播发间隔回退计时器功能应可配置。
Sections 5 and 6 provide configurable mechanisms to bound the number of re-advertisements. Instability might occur in very large networks if measurement intervals are set low enough to overwhelm the processing of flooded information at some of the routers in the topology. Therefore, care should be taken in setting these values.
第5节和第6节提供了可配置的机制来限制重新发布的数量。如果测量间隔设置得足够低，足以覆盖拓扑中某些路由器对泛洪信息的处理，则在非常大的网络中可能会发生不稳定性。因此，在设置这些值时应小心。
Additionally, the default measurement interval for all sub-TLVs SHOULD be 30 seconds.
此外，所有子TLV的默认测量间隔应为30秒。
Announcements MUST also be able to be throttled using configurable inter-update throttle timers. The minimum announcement periodicity is one announcement per second. The default value SHOULD be set to 120 seconds.
公告还必须能够使用可配置的更新间调节计时器进行调节。最短公告周期为每秒一次公告。默认值应设置为120秒。
Implementations SHOULD NOT permit the inter-update timer to be lower than the measurement interval.
实施不应允许更新间计时器低于测量间隔。
Furthermore, it is RECOMMENDED that any underlying performance-measurement mechanisms not include any significant buffer delay, any significant buffer-induced delay variation, or any significant loss due to buffer overflow or due to active queue management.
此外，建议任何底层性能度量机制不包括任何显著的缓冲区延迟、任何显著的缓冲区引起的延迟变化，或由于缓冲区溢出或主动队列管理而导致的任何显著损失。
Implementations MUST make it possible to individually enable or disable each sub-TLV based on configuration.
实现必须能够根据配置单独启用或禁用每个子TLV。
Implementations SHOULD permit static configuration and/or manual override of dynamic measurements for each sub-TLV in order to simplify migration and to mitigate scenarios where dynamic measurements are not possible.
实施应允许静态配置和/或手动覆盖每个子TLV的动态测量，以简化迁移并缓解不可能进行动态测量的情况。
As per [RFC5305], unrecognized sub-TLVs should be silently ignored.
根据[RFC5305]，未识别的子TLV应被静默忽略。
The sub-TLVs introduced in this document allow an operator to advertise state information of links (bandwidth, delay) that could be sensitive and that an operator may not want to disclose.
本文档中介绍的子TLV允许运营商公布链路的状态信息（带宽、延迟），这些信息可能是敏感的，运营商可能不想披露。
Section 7 describes a mechanism to ensure network stability when the new sub-TLVs defined in this document are advertised.
第7节描述了在公布本文件中定义的新子TLV时确保网络稳定性的机制。
Implementations SHOULD follow the described guidelines to mitigate the risk of instability.
实施应遵循所描述的指导原则，以降低不稳定的风险。
[RFC5304] describes an authentication method for IS-IS Link State PDUs that allows cryptographic authentication of IS-IS Link State PDUs.
[RFC5304]描述了IS-IS链路状态PDU的身份验证方法，该方法允许对IS-IS链路状态PDU进行加密身份验证。
It is anticipated that in most deployments, the IS-IS protocol is used within an infrastructure entirely under the control of the same operator. However, it is worth considering that the effect of sending IS-IS Traffic Engineering sub-TLVs over insecure links could include a man-in-the-middle attacker delaying real-time data to a given site or destination; this could negatively affect the value of the data for that site or destination. The use of Link State PDU cryptographic authentication allows mitigation of the risk of man-in-the-middle attacks.
预计在大多数部署中，is-is协议在完全由同一运营商控制的基础设施内使用。然而，值得考虑的是，通过不安全链路发送is-is流量工程子TLV的影响可能包括中间人攻击者将实时数据延迟到给定站点或目的地；这可能会对该站点或目标的数据值产生负面影响。使用链路状态PDU加密身份验证可以降低中间人攻击的风险。
IANA maintains the registry for the sub-TLVs. IANA has registered the following sub-TLVs in the "Sub-TLVs for TLVs 22, 23, 141, 222, and 223" registry:
IANA维护子TLV的注册表。IANA已在“第22、23、141、222和223号TLV的子TLV”注册表中注册了以下子TLV：
Type Description
----------------------------------------------------
33 Unidirectional Link Delay
Type Description
----------------------------------------------------
33 Unidirectional Link Delay
34 Min/Max Unidirectional Link Delay
34最小/最大单向链路延迟
35 Unidirectional Delay Variation
35单向延迟变化
36 Unidirectional Link Loss
36单向链路损耗
37 Unidirectional Residual Bandwidth
37单向剩余带宽
38 Unidirectional Available Bandwidth
38单向可用带宽
39 Unidirectional Utilized Bandwidth
39单向利用带宽
[IEEE754] Institute of Electrical and Electronics Engineers, "IEEE Standard for Floating-Point Arithmetic", IEEE Std 754-2008.
[IEEE754]电气和电子工程师协会，“IEEE浮点运算标准”，IEEE标准754-2008。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://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<https://www.rfc-editor.org/info/rfc2119>.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE)", RFC 4206, DOI 10.17487/RFC4206, October 2005, <https://www.rfc-editor.org/info/rfc4206>.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP) Hierarchy with Generalized Multi-Protocol Label Switching (GMPLS) Traffic Engineering (TE)", RFC 4206, DOI 10.17487/RFC4206, October 2005, <https://www.rfc-editor.org/info/rfc4206>.translate error, please retry
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, DOI 10.17487/RFC5120, February 2008, <https://www.rfc-editor.org/info/rfc5120>.
[RFC5120]Przygienda，T.，Shen，N.，和N.Sheth，“M-ISIS：中间系统到中间系统（IS-ISs）的多拓扑（MT）路由”，RFC 5120，DOI 10.17487/RFC5120，2008年2月<https://www.rfc-editor.org/info/rfc5120>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic Authentication", RFC 5304, DOI 10.17487/RFC5304, October 2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5304]Li，T.和R.Atkinson，“IS-IS加密认证”，RFC 5304，DOI 10.17487/RFC5304，2008年10月<https://www.rfc-editor.org/info/rfc5304>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October 2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC5305]Li，T.和H.Smit，“交通工程的IS-IS扩展”，RFC 5305，DOI 10.17487/RFC5305，2008年10月<https://www.rfc-editor.org/info/rfc5305>.
[RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in Support of Inter-Autonomous System (AS) MPLS and GMPLS Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, December 2008, <https://www.rfc-editor.org/info/rfc5316>.
[RFC5316]Chen，M.，Zhang，R.，和X.Duan，“支持自治系统间MPLS和GMPLS流量工程的ISIS扩展”，RFC 5316，DOI 10.17487/RFC5316，2008年12月<https://www.rfc-editor.org/info/rfc5316>.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, February 2011, <https://www.rfc-editor.org/info/rfc6119>.
[RFC6119]Harrison，J.，Berger，J.，和M.Bartlett，“IS-IS中的IPv6流量工程”，RFC 6119，DOI 10.17487/RFC6119，2011年2月<https://www.rfc-editor.org/info/rfc6119>.
[RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. Previdi, "OSPF Traffic Engineering (TE) Metric Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, <https://www.rfc-editor.org/info/rfc7471>.
[RFC7471]Giacalone，S.，Ward，D.，Drake，J.，Atlas，A.，和S.Previdi，“OSPF交通工程（TE）度量扩展”，RFC 7471，DOI 10.17487/RFC7471，2015年3月<https://www.rfc-editor.org/info/rfc7471>.
[RFC7810] Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions", RFC 7810, DOI 10.17487/RFC7810, May 2016, <https://www.rfc-editor.org/info/rfc7810>.
[RFC7810]Previdi，S.，Ed.，Giacalone，S.，Ward，D.，Drake，J.，和Q.Wu，“IS-IS交通工程（TE）度量扩展”，RFC 7810，DOI 10.17487/RFC7810，2016年5月<https://www.rfc-editor.org/info/rfc7810>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, <https://www.rfc-editor.org/info/rfc3209>.
[RFC3209]Awduche，D.，Berger，L.，Gan，D.，Li，T.，Srinivasan，V.，和G.Swallow，“RSVP-TE：LSP隧道RSVP的扩展”，RFC 3209，DOI 10.17487/RFC3209，2001年12月<https://www.rfc-editor.org/info/rfc3209>.
[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, <https://www.rfc-editor.org/info/rfc4203>.
[RFC4203]Kompella，K.，Ed.和Y.Rekhter，Ed.，“支持通用多协议标签交换（GMPLS）的OSPF扩展”，RFC 4203，DOI 10.17487/RFC4203，2005年10月<https://www.rfc-editor.org/info/rfc4203>.
[RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS Networks", RFC 6374, DOI 10.17487/RFC6374, September 2011, <https://www.rfc-editor.org/info/rfc6374>.
[RFC6374]Frost，D.和S.Bryant，“MPLS网络的数据包丢失和延迟测量”，RFC 6374，DOI 10.17487/RFC6374，2011年9月<https://www.rfc-editor.org/info/rfc6374>.
[RFC6375] Frost, D., Ed. and S. Bryant, Ed., "A Packet Loss and Delay Measurement Profile for MPLS-Based Transport Networks", RFC 6375, DOI 10.17487/RFC6375, September 2011, <https://www.rfc-editor.org/info/rfc6375>.
[RFC6375]Frost，D.，Ed.和S.Bryant，Ed.，“基于MPLS的传输网络的数据包丢失和延迟测量模式”，RFC 6375，DOI 10.17487/RFC6375，2011年9月<https://www.rfc-editor.org/info/rfc6375>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S., Previdi, S., Roome, W., Shalunov, S., and R. Woundy, "Application-Layer Traffic Optimization (ALTO) Protocol", RFC 7285, DOI 10.17487/RFC7285, September 2014, <https://www.rfc-editor.org/info/rfc7285>.
[RFC7285]Alimi，R.，Ed.，Penno，R.，Ed.，Yang，Y.，Ed.，Kiesel，S.，Previdi，S.，Room，W.，Shalunov，S.，和R.Woundy，“应用层流量优化（ALTO）协议”，RFC 7285，DOI 10.17487/RFC7285，2014年9月<https://www.rfc-editor.org/info/rfc7285>.
[RFC8571] Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric Extensions", RFC 8571, DOI 10.17487/RFC8571, March 2019, <https://www.rfc-editor.org/info/rfc8571>.
[RFC8571]Ginsberg，L.，Ed.，Previdi，S.，Wu，Q.，Tantsura，J.，和C.Filsfils，“BGP-IGP流量工程性能度量扩展的链路状态（BGP-LS）广告”，RFC 8571，DOI 10.17487/RFC8571，2019年3月<https://www.rfc-editor.org/info/rfc8571>.
Errata ID 5293 (https://www.rfc-editor.org/errata/eid5293) correctly identified that in [RFC7810] the length associated with the following sub-TLVs did not match the figures associated with each:
勘误表ID 5293(https://www.rfc-editor.org/errata/eid5293)正确识别[RFC7810]中与以下子TLV相关的长度与每个子TLV相关的图不匹配：
37 Unidirectional Residual Bandwidth
37单向剩余带宽
38 Unidirectional Available Bandwidth
38单向可用带宽
39 Unidirectional Utilized Bandwidth
39单向利用带宽
The length specified was 4, which did not include the RESERVED field shown in the figures. Subsequent investigation revealed that some implementations had used the specified length (4) and omitted the RESERVED field while other implementations included the specified RESERVED field and used a length of 5.
指定的长度为4，不包括图中所示的保留字段。随后的调查显示，一些实现使用了指定的长度（4）并省略了保留字段，而其他实现包括指定的保留字段并使用了长度5。
Because these different implementation choices are not interoperable, it was decided that a bis version should be generated to resolve this ambiguity.
由于这些不同的实现选择不可互操作，因此决定应生成bis版本以解决此歧义。
The choice made here is to omit the unused RESERVED field from these sub-TLVs and use the length of 4. This matches the corresponding advertisements specified in the equivalent OSPF TE specification [RFC7471] and the corresponding BGP - Link State (BGP-LS) specification [RFC8571].
这里所做的选择是从这些子TLV中省略未使用的保留字段，并使用长度4。这与等效OSPF TE规范[RFC7471]和相应的BGP链路状态（BGP-LS）规范[RFC8571]中指定的相应播发相匹配。
Some minor editorial corrections have also been made.
还作了一些小的编辑修改。
Errata ID 5486 (https://www.rfc-editor.org/errata/eid5486) identified that in Section 4.6 of [RFC7810] the definition of available bandwidth on bundled links used a circular definition, i.e., it used "sum of the component link available bandwidths" when it should have used "sum of the component link residual bandwidths". This has been corrected and clarified.
勘误表ID 5486(https://www.rfc-editor.org/errata/eid5486)确定在[RFC7810]第4.6节中，捆绑链路上可用带宽的定义使用了循环定义，即，当其本应使用“组件链路剩余带宽之和”时，使用了“组件链路可用带宽之和”。这一点已得到纠正和澄清。
Acknowledgements
致谢
In [RFC7810], the authors recognized Ayman Soliman, Nabil Bitar, David McDysan, Edward Crabbe, Don Fedyk, Hannes Gredler, Uma Chunduri, Alvaro Retana, Brian Weis, and Barry Leiba for their contributions and reviews of this document.
在[RFC7810]中，作者认可了Ayman Soliman、Nabil Bitar、David McDysan、Edward Crabbe、Don Fedyk、Hannes Gredler、Uma Chunduri、Alvaro Retana、Brian Weis和Barry Leiba对本文件的贡献和评论。
The authors also recognized Curtis Villamizar for significant comments and direct content collaboration.
作者还认可Curtis Villamizar的重要评论和直接内容协作。
For this document, the authors thank Jeff Haas for identifying and reporting the incorrect encoding of the bandwidth-related sub-TLVs.
对于本文档，作者感谢Jeff Haas识别并报告了与带宽相关的子TLV的错误编码。
Contributors
贡献者
The following people contributed substantially to the content of this document and should be considered coauthors:
以下人员对本文件的内容做出了重大贡献，应被视为合著者：
Alia Atlas Juniper Networks United States of America Email: akatlas@juniper.net
Alia Atlas Juniper Networks美利坚合众国电子邮件：akatlas@juniper.net
Clarence Filsfils Cisco Systems, Inc. Belgium Email: cfilsfil@cisco.com
Clarence Filsfils Cisco Systems，Inc.比利时电子邮件：cfilsfil@cisco.com
Authors' Addresses
作者地址
Les Ginsberg (editor) Cisco Systems, Inc.
莱斯·金斯伯格（编辑）思科系统公司。
Email: ginsberg@cisco.com
Email: ginsberg@cisco.com
Stefano Previdi (editor) Huawei
斯蒂芬诺·普雷维迪（编辑）华为
Email: stefano@previdi.net
Email: stefano@previdi.net
Spencer Giacalone Microsoft
斯宾塞·贾卡隆微软公司
Email: spencer.giacalone@gmail.com
Email: spencer.giacalone@gmail.com
Dave Ward Cisco Systems, Inc.
戴夫·沃德思科系统公司。
Email: wardd@cisco.com
Email: wardd@cisco.com
John Drake Juniper Networks 1194 N. Mathilda Ave. Sunnyvale, CA 94089 United States of America
约翰·德雷克·朱尼珀网络公司，美国加利福尼亚州桑尼维尔市马蒂尔达大道北1194号，邮编94089
Email: jdrake@juniper.net
Email: jdrake@juniper.net
Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China
中国江苏省南京市雨花区华为软件大道101号秦武210012
Email: bill.wu@huawei.com
Email: bill.wu@huawei.com