Internet Engineering Task Force (IETF) J. Snijders
Request for Comments: 8195 J. Heasley
Category: Informational NTT
ISSN: 2070-1721 M. Schmidt
i3D.net
June 2017
Internet Engineering Task Force (IETF) J. Snijders
Request for Comments: 8195 J. Heasley
Category: Informational NTT
ISSN: 2070-1721 M. Schmidt
i3D.net
June 2017
Use of BGP Large Communities
使用BGP大型社区
Abstract
摘要
This document presents examples and inspiration for operator application of BGP Large Communities. Based on operational experience with BGP Communities, this document suggests logical categories of BGP Large Communities and demonstrates an orderly manner of organizing community values within them to achieve typical goals in routing policy. Any operator can consider using the concepts presented as the basis for their own BGP Large Communities repertoire.
本文件为BGP大型社区的运营商应用提供了示例和启示。根据BGP社区的运营经验，本文件建议了BGP大型社区的逻辑类别，并展示了在这些社区内有序组织社区价值观的方式，以实现路由策略中的典型目标。任何运营商都可以考虑使用作为自己BGP大社区剧目的基础的概念。
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 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). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see 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。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 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc8195.
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/rfc8195.
Copyright Notice
版权公告
Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2017 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Design Overview . . . . . . . . . . . . . . . . . . . . . 3
2.1. Informational Communities . . . . . . . . . . . . . . . . 4
2.2. Action Communities . . . . . . . . . . . . . . . . . . . 5
3. Examples of Informational Communities . . . . . . . . . . . . 5
3.1. Location . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1. An ISO 3166-1 Numeric Function . . . . . . . . . . . 6
3.1.2. A UN M.49 Region Function . . . . . . . . . . . . . . 6
3.2. Relation Function . . . . . . . . . . . . . . . . . . . . 7
3.3. Combining Informational Communities . . . . . . . . . . . 7
4. Examples of Action Communities . . . . . . . . . . . . . . . 7
4.1. Selective NO_EXPORT . . . . . . . . . . . . . . . . . . . 7
4.1.1. ASN-Based Selective NO_EXPORT . . . . . . . . . . . . 8
4.1.2. Location-Based Selective NO_EXPORT . . . . . . . . . 8
4.2. Selective AS_PATH Prepending . . . . . . . . . . . . . . 9
4.2.1. ASN-Based Selective AS_PATH Prepending . . . . . . . 9
4.2.2. Location-Based Selective AS_PATH Prepending . . . . . 10
4.3. Manipulation of the LOCAL_PREF Attribute . . . . . . . . 10
4.3.1. Global Manipulation of LOCAL_PREF . . . . . . . . . . 11
4.3.2. Region-Based Manipulation of LOCAL_PREF . . . . . . . 11
4.3.3. Note of Caution for LOCAL_PREF Functions . . . . . . 12
4.4. Route Server Prefix Distribution Control . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Design Overview . . . . . . . . . . . . . . . . . . . . . 3
2.1. Informational Communities . . . . . . . . . . . . . . . . 4
2.2. Action Communities . . . . . . . . . . . . . . . . . . . 5
3. Examples of Informational Communities . . . . . . . . . . . . 5
3.1. Location . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1. An ISO 3166-1 Numeric Function . . . . . . . . . . . 6
3.1.2. A UN M.49 Region Function . . . . . . . . . . . . . . 6
3.2. Relation Function . . . . . . . . . . . . . . . . . . . . 7
3.3. Combining Informational Communities . . . . . . . . . . . 7
4. Examples of Action Communities . . . . . . . . . . . . . . . 7
4.1. Selective NO_EXPORT . . . . . . . . . . . . . . . . . . . 7
4.1.1. ASN-Based Selective NO_EXPORT . . . . . . . . . . . . 8
4.1.2. Location-Based Selective NO_EXPORT . . . . . . . . . 8
4.2. Selective AS_PATH Prepending . . . . . . . . . . . . . . 9
4.2.1. ASN-Based Selective AS_PATH Prepending . . . . . . . 9
4.2.2. Location-Based Selective AS_PATH Prepending . . . . . 10
4.3. Manipulation of the LOCAL_PREF Attribute . . . . . . . . 10
4.3.1. Global Manipulation of LOCAL_PREF . . . . . . . . . . 11
4.3.2. Region-Based Manipulation of LOCAL_PREF . . . . . . . 11
4.3.3. Note of Caution for LOCAL_PREF Functions . . . . . . 12
4.4. Route Server Prefix Distribution Control . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 14
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
BGP Large Communities [RFC8092] provide a mechanism to signal opaque information between and within Autonomous Systems (ASes). In very much the same way that [RFC1998] provides a concrete real-world application for BGP Communities [RFC1997], this document presents examples of how operators might utilize BGP Large Communities to achieve various goals. This document draws on the experience of operator communities such as the North American Network Operators' Group (NANOG) <https://www.nanog.org/> and the Netherlands Network Operator Group (NLNOG) <https://nlnog.net/>.
BGP大型社区[RFC8092]提供了一种在自治系统（ASE）之间和内部传递不透明信息的机制。与[RFC1998]为BGP社区[RFC1997]提供了一个具体的实际应用程序的方式非常相似，本文档提供了运营商如何利用BGP大型社区实现各种目标的示例。本文件借鉴了运营商社区的经验，如北美网络运营商集团（NANOG）<https://www.nanog.org/>荷兰网络运营商集团（NLNOG）<https://nlnog.net/>.
BGP Large Communities are composed of three 4-octet fields. The first is the Global Administrator (GA) field, whose value is the Autonomous System Number (ASN) of the AS that has defined the meaning of the remaining two 4-octet fields, known as "Local Data Part 1" and "Local Data Part 2". This document describes an approach where the "Local Data Part 1" field contains a function identifier and the "Local Data Part 2" contains a parameter value. Using the canonical notation this format can be summarized as "ASN:Function:Parameter".
BGP大型社区由三个4-octet字段组成。第一个是全局管理员（GA）字段，其值是AS的自治系统编号（ASN），该编号定义了其余两个4-octet字段的含义，称为“本地数据部分1”和“本地数据部分2”。本文档描述了一种方法，“本地数据第1部分”字段包含函数标识符，“本地数据第2部分”包含参数值。使用规范符号，这种格式可以概括为“ASN:Function:Parameter”。
+----------------------+---------------+
| RFC 8092 | this document |
+----------------------+---------------+
| Global Administrator | ASN |
| Local Data Part 1 | Function |
| Local Data Part 2 | Parameter |
+----------------------+---------------+
+----------------------+---------------+
| RFC 8092 | this document |
+----------------------+---------------+
| Global Administrator | ASN |
| Local Data Part 1 | Function |
| Local Data Part 2 | Parameter |
+----------------------+---------------+
Table 1: Field Mapping
表1：字段映射
The table above shows a mapping table between the fields in BGP Large Communities [RFC8092] and this document.
上表显示了BGP大型社区[RFC8092]中的字段与本文档之间的映射表。
In contemporary deployments of both BGP Communities [RFC1997] and BGP Large Communities [RFC8092], the function of a community can be divided into two categories:
在BGP社区[RFC1997]和BGP大型社区[RFC8092]的当代部署中，社区的功能可分为两类：
o Informational Communities
o 信息社区
o Action Communities
o 行动社区
Throughout the document, a topology of four ASes is used to illustrate the use of communities in the following configuration:
在整个文档中，四个ASE的拓扑用于说明社区在以下配置中的使用：
AS 65551
|
^
|
AS 64497
/ \
^ \
/ ^
AS 64498 \
| |
`<->- AS 64499
AS 65551
|
^
|
AS 64497
/ \
^ \
/ ^
AS 64498 \
| |
`<->- AS 64499
AS 64497 obtains transit services from (is a customer of) AS 65551, a 4-octet ASN. AS 64497 provides transit services to both AS 64498 and AS 64499. AS 64498 and AS 64499 maintain a peering relationship in which they only exchange their customer routes.
AS 64497从AS 65551（一个4-octet ASN）获得中转服务（是其客户）。AS 64497为AS 64498和AS 64499提供中转服务。AS 64498和AS 64499保持对等关系，在这种关系中，它们只交换其客户路由。
The opaque nature of BGP Large Communities allows for rapid deployment of new features or changes to their routing policy that perform an action. Operators are encouraged to publicly publish and maintain documentation on the purpose of each BGP Large Community, both Informational and Action, that they support or that are visible in BGP RIBs.
BGP大型社区的不透明性允许快速部署新功能或更改其路由策略以执行操作。鼓励运营商为其支持的或在BGP中可见的每个BGP大型社区公开发布和维护文档，包括信息和行动。
Informational Communities are labels for attributes such as the origin of the route announcement, the nature of the relation with an External BGP (EBGP) neighbor, or the intended propagation audience. Informational Communities can also assist in providing valuable information for day-to-day network operations such as debugging or capacity planning.
信息社区是属性的标签，例如路由公告的来源、与外部BGP（EBGP）邻居的关系性质或预期传播受众。信息社区还可以帮助为日常网络操作（如调试或容量规划）提供有价值的信息。
The Global Administrator field is set to the ASN of the network that tags the routes with the Informational Communities. For example, AS 64497 might add a community with the GA 64497 to a route accepted from an Internal BGP (IBGP) or EBGP neighbor as a means of signaling that it was imported in a certain geographical region.
“全局管理员”字段设置为网络的ASN，该网络使用信息社区标记路由。例如，AS 64497可以将带有GA 64497的社区添加到从内部BGP（IBGP）或EBGP邻居接受的路由中，作为在特定地理区域导入该社区的信令方式。
In general, the intended audiences of Informational Communities are downstream networks and the GA itself, but any AS could benefit from receiving these communities.
一般来说，信息社区的目标受众是下游网络和GA本身，但任何AS都可以从接收这些社区中受益。
Action Communities are added as labels to request that a route be treated in a particular way within an AS. The operator of the AS defines a routing policy that adjusts path attributes based on the community. For example, the route's propagation characteristics, the LOCAL_PREF (local preference), the next hop, or the number of AS_PATH prepends to be added when it is received or propagated can be changed.
将动作社区添加为标签，以请求在as中以特定方式处理路线。AS的运算符定义一个路由策略，该策略根据社区调整路径属性。例如，可以更改路由的传播特性、本地首选项（LOCAL PREF）、下一跳或接收或传播路由时要添加的AS_路径前缀数。
The Global Administrator field is set to the ASN that has defined the functionality of that BGP Large Community and is the ASN that is expected to perform the action. For example, AS 64499 might label a route with a BGP Large Community containing GA 64497 to request that AS 64497 perform a predefined action on that route.
全局管理员字段设置为已定义BGP大型社区功能的ASN，并且是预期执行操作的ASN。例如，AS 64499可能使用包含GA 64497的BGP大型社区标记路由，以请求AS 64497在该路由上执行预定义操作。
In general, the intended audience of Action Communities are transit providers taking action on behalf of a customer or the GA itself, but any AS could take action if they choose and any AS could add an Action Community with the GA of a non-adjacent ASN. However, note that an Action Community could also be Informational. Its presence is an indicator that the GA may have performed the action and that an AS in the AS_PATH requested it.
一般来说，行动社区的目标受众是代表客户或GA本身采取行动的交通服务提供商，但任何AS可以在其选择的情况下采取行动，任何AS都可以在非相邻ASN的GA中添加行动社区。但是，请注意，行动社区也可以是信息社区。它的存在表明GA可能已经执行了该动作，并且AS_路径中的AS请求了该动作。
Operators are recommended to publish the relative order in which Action Communities (both BGP Communities and BGP Large Communities) are processed in their routing policy.
建议运营商在其路由策略中发布操作社区（BGP社区和BGP大型社区）处理的相对顺序。
An AS, AS 64497 in these examples, may inform other networks about the geographical region where AS 64497 imported a route by labeling it with BGP Large Communities following one of the following schemes or a combination of them.
AS（在这些示例中为AS 64497）可通过使用BGP大型社区标记AS 64497导入路线的地理区域来通知其他网络，这些社区遵循以下方案之一或它们的组合。
AS 64497 could assign a value of 1 to the Function field to designate the content of the Parameter field as an ISO 3166-1 numeric country identifier <https://www.iso.org/iso-3166-country-codes.html>.
AS 64497可将值1分配给函数字段，以将参数字段的内容指定为ISO 3166-1数字国家标识符<https://www.iso.org/iso-3166-country-codes.html>.
+---------------------+---------------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------------+
| 64497:1:528 | Route learned in the Netherlands |
| 64497:1:392 | Route learned in Japan |
| 64497:1:840 | Route learned in the United States of |
| | America |
+---------------------+---------------------------------------------+
+---------------------+---------------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------------+
| 64497:1:528 | Route learned in the Netherlands |
| 64497:1:392 | Route learned in Japan |
| 64497:1:840 | Route learned in the United States of |
| | America |
+---------------------+---------------------------------------------+
Table 2: Informational: ISO 3166-1
表2：信息：ISO 3166-1
The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the location where a route was imported using ISO 3166-1 numeric identifiers.
上表显示了AS 64497部署的信息社区的示例文档，用于描述使用ISO 3166-1数字标识符导入路由的位置。
AS 64497 could assign a value of 2 to the Function field to designate the content of the Parameter field as the M.49 numeric code published by the United Nations Statistics Division (UNSD) <https://unstats.un.org/unsd/methodology/m49/> for macro-geographical (continental) regions, geographical sub-regions, or selected economic and other groupings.
AS 64497可以为函数字段指定一个值2，以将参数字段的内容指定为联合国统计司（UNSD）发布的M.49数字代码<https://unstats.un.org/unsd/methodology/m49/>对于宏观地理（大陆）区域、地理分区或选定的经济和其他分组。
+---------------------+-------------------------------+
| BGP Large Community | Description |
+---------------------+-------------------------------+
| 64497:2:2 | Route learned in Africa |
| 64497:2:9 | Route learned in Oceania |
| 64497:2:145 | Route learned in Western Asia |
| 64497:2:150 | Route learned in Europe |
+---------------------+-------------------------------+
+---------------------+-------------------------------+
| BGP Large Community | Description |
+---------------------+-------------------------------+
| 64497:2:2 | Route learned in Africa |
| 64497:2:9 | Route learned in Oceania |
| 64497:2:145 | Route learned in Western Asia |
| 64497:2:150 | Route learned in Europe |
+---------------------+-------------------------------+
Table 3: Informational: UNSD Regions
表3：信息：UNSD区域
The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the location where a route was imported using M.49 numeric codes published by the UNSD.
上表显示了AS 64497部署的信息社区的示例文档，用于描述使用UNSD发布的M.49数字代码导入路线的位置。
An AS, AS 64497 in this example, could assign a value of 3 to the Function field to designate the content of the Parameter field as a number indicating whether the route originated inside its own network or was learned externally, and if learned externally, it might simultaneously characterize the nature of the relation with that specific EBGP neighbor.
AS（本例中为AS 64497）可将值3分配给功能字段，以将参数字段的内容指定为一个数字，该数字指示路由是起源于其自身网络内部还是外部学习，如果从外部学习，它可能同时表征与该特定EBGP邻居的关系的性质。
+---------------------+---------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------+
| 64497:3:1 | Route originated internally |
| 64497:3:2 | Route learned from a customer |
| 64497:3:3 | Route learned from a peering partner |
| 64497:3:4 | Route learned from a transit provider |
+---------------------+---------------------------------------+
+---------------------+---------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------+
| 64497:3:1 | Route originated internally |
| 64497:3:2 | Route learned from a customer |
| 64497:3:3 | Route learned from a peering partner |
| 64497:3:4 | Route learned from a transit provider |
+---------------------+---------------------------------------+
Table 4: Informational: Relation
表4：信息：关系
The table above shows example documentation for Informational Communities deployed by AS 64497 to describe the relation to the ASN from which the route was learned.
上表显示了AS 64497部署的信息社区的示例文档，用于描述与从中学习路线的ASN的关系。
A route may be labeled with multiple Informational Communities. For example, a route learned in the Netherlands from a customer might be labeled with communities 64497:1:528, 64497:2:150, and 64497:3:2 at the same time.
一条路线可能标有多个信息社区。例如，在荷兰从客户那里了解到的路线可能同时标记为communities 64497:1:528、64497:2:150和64497:3:2。
As part of an agreement, often a commercial transit agreement, between AS 64497 and AS 64498, AS 64497 might expose BGP traffic-engineering functions to AS 64498. One such BGP traffic-engineering function could be selective NO_EXPORT, which is the selective filtering of a route learned from one AS, AS 64498, to certain EBGP neighbors of the GA, AS 64497.
作为协议的一部分，通常是As 64497和As 64498之间的商业运输协议，As 64497可能向As 64498公开BGP交通工程功能。一个这样的BGP流量工程功能可以是选择性NO_导出，这是选择性过滤从AS 64498学习到GA的某些EBGP邻居AS 64497的路由。
AS 64497 could assign a value of 4 to the Function field to designate the content of the Parameter field as a neighboring ASN to which a route should not be propagated.
AS 64497可将值4分配给函数字段，以将参数字段的内容指定为不应向其传播路由的相邻ASN。
+---------------------+---------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------+
| 64497:4:64498 | Do not export route to AS 64498 |
| 64497:4:64499 | Do not export route to AS 64499 |
| 64497:4:65551 | Do not export route to AS 65551 |
+---------------------+---------------------------------+
+---------------------+---------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------+
| 64497:4:64498 | Do not export route to AS 64498 |
| 64497:4:64499 | Do not export route to AS 64499 |
| 64497:4:65551 | Do not export route to AS 65551 |
+---------------------+---------------------------------+
Table 5: Action: ASN NO_EXPORT
表5：行动：ASN NO_导出
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that selectively prevents the propagation of routes to the neighboring ASN specified in the Parameter field.
上表显示了AS 64497部署的行动社区的示例文档，以公开BGP流量工程功能，该功能选择性地防止路由传播到参数字段中指定的相邻ASN。
AS 64497 could assign a value of 5 to the Function field to designate the content of the Parameter field as an ISO 3166-1 numeric country identifier within which a labeled route is not propagated to EBGP neighbors. However, this might not prevent one of those EBGP neighbors from learning that route in another country and making it available in the country specified by the BGP Large Community.
AS 64497可将值5分配给函数字段，以将参数字段的内容指定为ISO 3166-1数字国家标识符，其中标记的路由不会传播到EBGP邻居。然而，这可能不会阻止其中一个EBGP邻居在另一个国家学习该路线，并在BGP大型社区指定的国家提供该路线。
+-----------------+-------------------------------------------------+
| BGP Large | Description |
| Community | |
+-----------------+-------------------------------------------------+
| 64497:5:528 | Do not export to EBGP neighbors in the |
| | Netherlands |
| 64497:5:392 | Do not export to EBGP neighbors in Japan |
| 64497:5:840 | Do not export to EBGP neighbors in the United |
| | States of America |
+-----------------+-------------------------------------------------+
+-----------------+-------------------------------------------------+
| BGP Large | Description |
| Community | |
+-----------------+-------------------------------------------------+
| 64497:5:528 | Do not export to EBGP neighbors in the |
| | Netherlands |
| 64497:5:392 | Do not export to EBGP neighbors in Japan |
| 64497:5:840 | Do not export to EBGP neighbors in the United |
| | States of America |
+-----------------+-------------------------------------------------+
Table 6: Action: NO_EXPORT in Region
表6：行动：区域内无出口
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that selectively prevents the propagation of routes to all EBGP neighbors in the geographical region specified in the Parameter field.
上表显示了AS 64497部署的行动社区的示例文档，以公开BGP流量工程功能，该功能选择性地防止路由传播到参数字段中指定地理区域内的所有EBGP邻居。
As part of an agreement between AS 64497 and AS 64498, AS 64497 might expose BGP traffic-engineering functions to AS 64498. One such BGP traffic-engineering function could be selective prepending of the AS_PATH with AS 64497 to certain EBGP neighbors of AS 64497.
作为As 64497和As 64498之间协议的一部分，As 64497可能向As 64498公开BGP流量工程功能。一个这样的BGP流量工程功能可以是将AS 64497的AS_路径选择性地预编到AS 64497的某些EBGP邻居。
AS 64497 could assign a value of 6 to the Function field to designate the content of the Parameter field as a neighboring ASN to which prepending of the AS_PATH with AS 64497 is requested on propagation of the route. Additional AS_PATH prepending functions might also be defined to support multiples of prepending, that is, two, three, or more prepends of AS 64497.
AS 64497可将值6分配给功能字段，以将参数字段的内容指定为相邻ASN，在路由传播时，向其请求AS 64497的AS_路径的前置。还可以定义其他AS_路径预结束函数以支持多个预结束，即AS 64497的两个、三个或更多预结束。
+---------------------+------------------------------------------+
| BGP Large Community | Description |
+---------------------+------------------------------------------+
| 64497:6:64498 | Prepend 64497 once on export to AS 64498 |
| 64497:6:64499 | Prepend 64497 once on export to AS 64499 |
| 64497:6:65551 | Prepend 64497 once on export to AS 65551 |
+---------------------+------------------------------------------+
+---------------------+------------------------------------------+
| BGP Large Community | Description |
+---------------------+------------------------------------------+
| 64497:6:64498 | Prepend 64497 once on export to AS 64498 |
| 64497:6:64499 | Prepend 64497 once on export to AS 64499 |
| 64497:6:65551 | Prepend 64497 once on export to AS 65551 |
+---------------------+------------------------------------------+
Table 7: Action: Prepend to ASN
表7：行动：为ASN做准备
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that selectively prepends the AS_PATH with AS 64497 when propagating the route to the specified EBGP neighbor.
上表显示了AS 64497部署的操作社区的示例文档，以公开BGP流量工程功能，该功能在将路由传播到指定的EBGP邻居时，有选择地使用AS 64497预先设置AS_路径。
AS 64497 could assign a value of 7 to the Function field to designate the content of the Parameter field as an ISO 3166-1 numeric country identifier to which the prepending of the AS_PATH with AS 64497 is requested on propagation of the route to all EBGP neighbors in that region.
AS 64497可将值7分配给函数字段，以将参数字段的内容指定为ISO 3166-1数字国家标识符，当路由传播到该区域中的所有EBGP邻居时，AS 64497会请求AS_路径的前缀。
+-----------------+-------------------------------------------------+
| BGP Large | Description |
| Community | |
+-----------------+-------------------------------------------------+
| 64497:7:528 | Prepend once to EBGP neighbors in the |
| | Netherlands |
| 64497:7:392 | Prepend once to EBGP neighbors in Japan |
| 64497:7:840 | Prepend once to EBGP neighbors in the United |
| | States of America |
+-----------------+-------------------------------------------------+
+-----------------+-------------------------------------------------+
| BGP Large | Description |
| Community | |
+-----------------+-------------------------------------------------+
| 64497:7:528 | Prepend once to EBGP neighbors in the |
| | Netherlands |
| 64497:7:392 | Prepend once to EBGP neighbors in Japan |
| 64497:7:840 | Prepend once to EBGP neighbors in the United |
| | States of America |
+-----------------+-------------------------------------------------+
Table 8: Action: Prepend in Region
表8：行动：在区域内预先结束
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that selectively prepends the AS_PATH with AS 64497 when propagating the route to all EBGP neighbors in the geographical region specified in the Parameter field.
上表显示了AS 64497部署的行动社区的示例文档，以公开BGP流量工程功能，该功能在将路由传播到参数字段中指定的地理区域中的所有EBGP邻居时，有选择地使用AS 64497预先设置AS_路径。
As part of an agreement between AS 64497 and AS 64498, AS 64497 might expose BGP traffic-engineering functions to AS 64498. One such BGP traffic-engineering function might allow AS 64498 to manipulate the value of the LOCAL_PREF attribute of routes learned from AS 64498 within AS 64497, even though the LOCAL_PREF attribute is non-transitive and is not propagated to EBGP neighbors.
作为As 64497和As 64498之间协议的一部分，As 64497可能向As 64498公开BGP流量工程功能。一个这样的BGP流量工程功能可能允许AS 64498在AS 64497中操纵从AS 64498学习的路由的本地_PREF属性的值，即使本地_PREF属性是不可传递的，并且不会传播到EBGP邻居。
The LOCAL_PREF value of routes are locally significant within each AS and are impossible to list in this document. Instead, the typical LOCAL_PREF values could be classified as a hierarchy, and a BGP Large Community function could be exposed, allowing an EBGP neighbor to affect the LOCAL_PREF value within the specified GA. The following example list defines the classes of routes in the order of descending LOCAL_PREF value and assigns a function identifier that could be used in the Function field of a BGP Large Community.
路由的本地_PREF值在每个AS中都是本地重要的，不可能在本文档中列出。相反，可以将典型的本地_PREF值分类为一个层次结构，并公开BGP大型社区功能，允许EBGP邻居影响指定GA内的本地_PREF值。以下示例列表按本地_PREF值降序定义路由类，并分配可在BGP大型社区的函数字段中使用的函数标识符。
+----------+--------------------------------------------------------+
| Function | Preference Class |
+----------+--------------------------------------------------------+
| 8 | Normal customer route |
| 9 | Backup customer route |
| 10 | Peering route |
| 11 | Upstream transit route |
| 12 | Fallback route, to be installed if no other path is |
| | available |
+----------+--------------------------------------------------------+
+----------+--------------------------------------------------------+
| Function | Preference Class |
+----------+--------------------------------------------------------+
| 8 | Normal customer route |
| 9 | Backup customer route |
| 10 | Peering route |
| 11 | Upstream transit route |
| 12 | Fallback route, to be installed if no other path is |
| | available |
+----------+--------------------------------------------------------+
Table 9: Action: Preference Function Identifiers
表9：操作：首选函数标识符
AS 64497 could place one of the previously defined Preference Function Identifiers in the Function field and set the value 0 in the Parameter field to designate that the LOCAL_PREF associated with that function identifier should be applied for that route throughout the whole AS.
AS 64497可将先前定义的偏好功能标识符之一置于功能字段中，并在参数字段中设置值0，以指定与该功能标识符相关联的本地_PREF应在整个AS中应用于该路由。
+---------------------+---------------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------------+
| 64497:9:0 | Assign LOCAL_PREF for a customer backup |
| | route |
| 64497:10:0 | Assign LOCAL_PREF for a peering route |
| 64497:12:0 | Assign LOCAL_PREF for a fallback route |
+---------------------+---------------------------------------------+
+---------------------+---------------------------------------------+
| BGP Large Community | Description |
+---------------------+---------------------------------------------+
| 64497:9:0 | Assign LOCAL_PREF for a customer backup |
| | route |
| 64497:10:0 | Assign LOCAL_PREF for a peering route |
| 64497:12:0 | Assign LOCAL_PREF for a fallback route |
+---------------------+---------------------------------------------+
Table 10: Action: Global LOCAL_PREF Manipulation
表10：操作：全局-局部预处理
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that allows a BGP neighbor to globally manipulate the LOCAL_PREF attribute for the route within AS 64497.
上表显示了AS 64497部署的行动社区的示例文档，以公开BGP流量工程功能，该功能允许BGP邻居全局操作AS 64497内路由的本地_PREF属性。
AS 64497 could place one of the previously defined Preference Function Identifiers in the Function field and use a UN M.49 numeric region identifier in the Parameter field to designate the geographical region within which the non-default LOCAL_PREF associated with that function identifier should be applied to the route. The value of the LOCAL_PREF attribute should not deviate from the default for that route class in any region not specified by one or more of these Action Communities.
AS 64497可在功能字段中放置一个先前定义的偏好功能标识符，并在参数字段中使用UN M.49数字区域标识符来指定地理区域，在该地理区域内，与该功能标识符关联的非默认本地_PREF应应用于路由。LOCAL_PREF属性的值不应偏离一个或多个操作社区未指定的任何区域中该路由类的默认值。
+--------------+----------------------------------------------------+
| BGP Large | Description |
| Community | |
+--------------+----------------------------------------------------+
| 64497:9:3 | Assign the LOCAL_PREF value equivalent to a |
| | customer backup class route on BGP routers in the |
| | North America region |
| 64497:10:5 | Assign the LOCAL_PREF value equivalent to a |
| | peering class route on BGP routers in the South |
| | America region |
| 64497:12:142 | Assign the LOCAL_PREF value equivalent to a |
| | fallback class route on BGP routers in the Asia |
| | region |
+--------------+----------------------------------------------------+
+--------------+----------------------------------------------------+
| BGP Large | Description |
| Community | |
+--------------+----------------------------------------------------+
| 64497:9:3 | Assign the LOCAL_PREF value equivalent to a |
| | customer backup class route on BGP routers in the |
| | North America region |
| 64497:10:5 | Assign the LOCAL_PREF value equivalent to a |
| | peering class route on BGP routers in the South |
| | America region |
| 64497:12:142 | Assign the LOCAL_PREF value equivalent to a |
| | fallback class route on BGP routers in the Asia |
| | region |
+--------------+----------------------------------------------------+
Table 11: Action: Regional LOCAL_PREF Manipulation
表11：行动：区域本地预处理
The table above shows example documentation for Action Communities deployed by AS 64497 to expose a BGP traffic-engineering function that allows a BGP neighbor to selectively manipulate the LOCAL_PREF attribute within AS 64497 in the geographical region specified in the Parameter field.
上表显示了AS 64497部署的操作社区的示例文档，以公开BGP流量工程功能，该功能允许BGP邻居在参数字段中指定的地理区域内选择性地操作AS 64497中的本地_PREF属性。
The LOCAL_PREF attribute strongly influences the BGP Decision Process, which in turn affects the scope of route propagation. Operators should take special care when using Action Communities that decrease the LOCAL_PREF value, and the degree of preference, to a value below that of another route class. Some of the unintended BGP states that might arise as a result of these traffic-engineering decisions are described as "BGP Wedgies" in [RFC4264].
LOCAL_PREF属性强烈影响BGP决策过程，进而影响路由传播的范围。操作员在使用将本地_PREF值和偏好度降低到低于另一路由类别的值的操作社区时，应特别小心。[RFC4264]中将这些流量工程决策可能导致的一些非预期BGP状态描述为“BGP楔子”。
Route servers [RFC7947] use BGP to broker network reachability information among their clients. As not all route server clients may wish to interconnect with each other, the route server operator will usually implement a mechanism to allow each client to control the route server's export routing policy, as described in Section 4.6 of [RFC7948]. One widely used mechanism is an adaption of "ASN-Based Selective NO_EXPORT" (Section 4.1.1) that is specific to route servers.
路由服务器[RFC7947]使用BGP在其客户端之间代理网络可达性信息。由于并非所有路由服务器客户端都希望彼此互连，路由服务器运营商通常会实施一种机制，允许每个客户端控制路由服务器的导出路由策略，如[RFC7948]第4.6节所述。一种广泛使用的机制是针对路由服务器的“基于ASN的选择性NO_导出”（第4.1.1节）的自适应。
An example BGP Large Communities policy that enables client-controlled prefix distribution for a route server operating as AS 64511 is outlined as follows:
为按as 64511运行的路由服务器启用客户端控制的前缀分发的示例BGP大型社区策略概述如下：
+-------------------+-----------------------------------------------+
| BGP Large | Description |
| Community | |
+-------------------+-----------------------------------------------+
| 64511:0:peer-as | Explicitly prevent announcement of route to |
| | peer-as |
| 64511:1:peer-as | Explicitly announce route to peer-as |
| 64511:0:0 | Do not announce route to any peers by default |
| 64511:1:0 | Announce route to all peers by default |
+-------------------+-----------------------------------------------+
+-------------------+-----------------------------------------------+
| BGP Large | Description |
| Community | |
+-------------------+-----------------------------------------------+
| 64511:0:peer-as | Explicitly prevent announcement of route to |
| | peer-as |
| 64511:1:peer-as | Explicitly announce route to peer-as |
| 64511:0:0 | Do not announce route to any peers by default |
| 64511:1:0 | Announce route to all peers by default |
+-------------------+-----------------------------------------------+
Table 12: Action: Route Server Prefix Distribution Control
表12：操作：路由服务器前缀分发控制
Multiple BGP Large Community values can be used together to implement fine-grained route distribution control. For example, route server client AS 64500 might wish to use a route server for interconnecting to all other clients except AS 64509. In this case, they would label all their outbound routes to the route server with 64511:1:0 (to announce to all clients by default) and 64511:0:64509 (to prevent announcement to AS 64509).
多个BGP大型社区值可以一起使用，以实现细粒度路由分布控制。例如，路由服务器客户端AS 64500可能希望使用路由服务器互连到除AS 64509之外的所有其他客户端。在这种情况下，他们将使用64511:1:0（默认情况下向所有客户机公告）和64511:0:64509（防止向AS 64509公告）标记所有到路由服务器的出站路由。
Alternatively, route server client AS 64501 may have a selective routing policy and may wish to interconnect with only AS 64505 and AS 64506. This could be implemented by announcing routes labeled with 64511:0:0 (blocking all distribution by default) and 64511:1:64505, 64511:1:64506 to instruct the route server to force announcement to those two ASNs.
或者，路由服务器客户端AS 64501可以具有选择性路由策略，并且可能希望仅与AS 64505和AS 64506互连。这可以通过通告标有64511:0:0（默认情况下阻止所有分发）和64511:1:64505、64511:1:64506的路由来实现，以指示路由服务器强制通告这两个ASN。
Operators should note the recommendations in Section 11 of "BGP Operations and Security" [RFC7454] and handle BGP Large Communities with their ASN in the Global Administrator field similarly.
运营商应注意“BGP运营和安全”[RFC7454]第11节中的建议，并在全球管理员字段中使用其ASN处理BGP大型社区。
In particular and in the same respect as BGP Communities [RFC1997], operators should be cognizant that any Large Community can be carried in a BGP UPDATE. Operators should recognize that BGP neighbors, particularly customers and customers of customers, may utilize communities defined by other BGP neighbors of the operator. They may wish to send routes with Action Communities and receive routes with Informational Communities to or from these other neighbors, and it is beneficial to all to permit this.
特别是，在与BGP社区[RFC1997]相同的方面，运营商应该认识到，任何大型社区都可以在BGP更新中进行。运营商应认识到，BGP邻居，特别是客户和客户的客户，可以利用由运营商的其他BGP邻居定义的社区。他们可能希望通过行动社区发送路线，并通过信息社区接收通往或来自这些其他邻居的路线，允许这样做对所有人都有利。
This document does not require any IANA actions.
本文件不要求IANA采取任何行动。
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, <http://www.rfc-editor.org/info/rfc1997>.
[RFC1997]Chandra，R.，Traina，P.，和T.Li，“BGP社区属性”，RFC 1997，DOI 10.17487/RFC1997，1996年8月<http://www.rfc-editor.org/info/rfc1997>.
[RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, February 2015, <http://www.rfc-editor.org/info/rfc7454>.
[RFC7454]Durand，J.，Pepelnjak，I.，和G.Doering，“BGP运营和安全”，BCP 194，RFC 7454，DOI 10.17487/RFC7454，2015年2月<http://www.rfc-editor.org/info/rfc7454>.
[RFC8092] Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas, I., and N. Hilliard, "BGP Large Communities Attribute", RFC 8092, DOI 10.17487/RFC8092, February 2017, <http://www.rfc-editor.org/info/rfc8092>.
[RFC8092]Heitz，J.，Ed.，Snijders，J.，Ed.，Patel，K.，Bagdonas，I.，和N.Hilliard，“BGP大社区属性”，RFC 8092，DOI 10.17487/RFC8092，2017年2月<http://www.rfc-editor.org/info/rfc8092>.
[RFC1998] Chen, E. and T. Bates, "An Application of the BGP Community Attribute in Multi-home Routing", RFC 1998, DOI 10.17487/RFC1998, August 1996, <http://www.rfc-editor.org/info/rfc1998>.
[RFC1998]Chen，E.和T.Bates，“BGP社区属性在多家路由中的应用”，RFC 1998，DOI 10.17487/RFC1998，1996年8月<http://www.rfc-editor.org/info/rfc1998>.
[RFC4264] Griffin, T. and G. Huston, "BGP Wedgies", RFC 4264, DOI 10.17487/RFC4264, November 2005, <http://www.rfc-editor.org/info/rfc4264>.
[RFC4264]Griffin，T.和G.Huston，“BGP楔子”，RFC 4264，DOI 10.17487/RFC4264，2005年11月<http://www.rfc-editor.org/info/rfc4264>.
[RFC7947] Jasinska, E., Hilliard, N., Raszuk, R., and N. Bakker, "Internet Exchange BGP Route Server", RFC 7947, DOI 10.17487/RFC7947, September 2016, <http://www.rfc-editor.org/info/rfc7947>.
[RFC7947]Jasinska，E.，Hilliard，N.，Raszuk，R.，和N.Bakker，“互联网交换BGP路由服务器”，RFC 7947，DOI 10.17487/RFC7947，2016年9月<http://www.rfc-editor.org/info/rfc7947>.
[RFC7948] Hilliard, N., Jasinska, E., Raszuk, R., and N. Bakker, "Internet Exchange BGP Route Server Operations", RFC 7948, DOI 10.17487/RFC7948, September 2016, <http://www.rfc-editor.org/info/rfc7948>.
[RFC7948]Hilliard，N.，Jasinska，E.，Raszuk，R.，和N.Bakker，“互联网交换BGP路由服务器操作”，RFC 7948，DOI 10.17487/RFC7948，2016年9月<http://www.rfc-editor.org/info/rfc7948>.
Acknowledgments
致谢
The authors would like to gratefully acknowledge the insightful comments, contributions, critique, and support from Adam Chappell, Jonathan Stewart, Greg Hankins, Nick Hilliard, Will Hargrave, Randy Bush, Shawn Morris, Jay Borkenhagen, and Stewart Bryant.
作者衷心感谢亚当·查佩尔、乔纳森·斯图尔特、格雷格·汉金斯、尼克·希利亚德、威尔·哈格雷夫、兰迪·布什、肖恩·莫里斯、杰·博肯哈根和斯图尔特·布莱恩特的富有洞察力的评论、贡献、批评和支持。
Authors' Addresses
作者地址
Job Snijders NTT Communications Theodorus Majofskistraat 100 Amsterdam 1065 SZ The Netherlands
Job Snijders NTT Communications Theodorus Majofskistraat 100阿姆斯特丹1065 SZ荷兰
Email: job@ntt.net
Email: job@ntt.net
John Heasley NTT Communications 1111 NW 53rd Drive Portland, OR 97210 United States of America
美国波特兰第53大道西北1111号，邮编：97210
Email: heas@shrubbery.net
Email: heas@shrubbery.net
Martijn Schmidt i3D.net Rivium 1e Straat 1 Capelle aan den IJssel 2909 LE The Netherlands
Martijn Schmidt i3D.net荷兰卡佩勒艾瑟尔酒店1号里维埃1e街2909号
Email: martijnschmidt@i3d.net
Email: martijnschmidt@i3d.net