Network Working Group D. Meyer
Request for Comments: 4384 February 2006
BCP: 114
Category: Best Current Practice
Network Working Group D. Meyer
Request for Comments: 4384 February 2006
BCP: 114
Category: Best Current Practice
BGP Communities for Data Collection
用于数据收集的BGP社区
Status of This Memo
关于下段备忘
This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited.
本文件规定了互联网社区的最佳现行做法，并要求进行讨论和提出改进建议。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2006).
版权所有（C）互联网协会（2006年）。
Abstract
摘要
BGP communities (RFC 1997) are used by service providers for many purposes, including tagging of customer, peer, and geographically originated routes. Such tagging is typically used to control the scope of redistribution of routes within a provider's network and to its peers and customers. With the advent of large-scale BGP data collection (and associated research), it has become clear that the information carried in such communities is essential for a deeper understanding of the global routing system. This memo defines standard (outbound) communities and their encodings for export to BGP route collectors.
BGP社区（RFC 1997）被服务提供商用于多种目的，包括标记客户、对等方和地理来源的路线。此类标记通常用于控制供应商网络内以及其对等方和客户的路由重新分配范围。随着大规模BGP数据收集（和相关研究）的出现，很明显，这些社区中携带的信息对于深入了解全球路由系统至关重要。此备忘录定义标准（出站）社区及其编码，以便导出到BGP路由收集器。
Table of Contents
目录
1. Introduction ....................................................2
2. Definitions .....................................................3
2.1. Peers and Peering ..........................................3
2.2. Customer Routes ............................................3
2.3. Peer Routes ................................................3
2.4. Internal Routes ............................................4
2.5. Internal More Specific Routes ..............................4
2.6. Special Purpose Routes .....................................4
2.7. Upstream Routes ............................................4
2.8. National Routes ............................................4
2.9. Regional Routes ............................................4
3. RFC 1997 Community Encoding and Values ..........................5
4. Community Values for BGP Data Collection ........................5
4.1. Extended Communities .......................................7
4.2. Four-Octet AS Specific Extended Communities ................9
5. Note on BGP UPDATE Packing ......................................9
6. Acknowledgements ................................................9
7. Security Considerations ........................................10
7.1. Total Path Attribute Length ...............................10
8. IANA Considerations ............................................10
9. References .....................................................11
9.1. Normative References ......................................11
9.2. Informative References ....................................11
1. Introduction ....................................................2
2. Definitions .....................................................3
2.1. Peers and Peering ..........................................3
2.2. Customer Routes ............................................3
2.3. Peer Routes ................................................3
2.4. Internal Routes ............................................4
2.5. Internal More Specific Routes ..............................4
2.6. Special Purpose Routes .....................................4
2.7. Upstream Routes ............................................4
2.8. National Routes ............................................4
2.9. Regional Routes ............................................4
3. RFC 1997 Community Encoding and Values ..........................5
4. Community Values for BGP Data Collection ........................5
4.1. Extended Communities .......................................7
4.2. Four-Octet AS Specific Extended Communities ................9
5. Note on BGP UPDATE Packing ......................................9
6. Acknowledgements ................................................9
7. Security Considerations ........................................10
7.1. Total Path Attribute Length ...............................10
8. IANA Considerations ............................................10
9. References .....................................................11
9.1. Normative References ......................................11
9.2. Informative References ....................................11
BGP communities [RFC1997] are used by service providers for many purposes, including tagging of customer, peer, and geographically originated routes. Such tagging is typically used to control the scope of redistribution of routes within a provider's network and to its customers and peers. Communities are also used for a wide variety of other applications, such as allowing customers to set attributes such as LOCAL_PREF [RFC1771] by sending appropriate communities to their service provider. Other applications include signaling various types of Virtual Private Networks (VPNs) (e.g., Virtual Private LAN Service (VPLS) [VPLS]), and carrying link bandwidth for traffic engineering applications [RFC4360].
BGP社区[RFC1997]被服务提供商用于多种目的，包括标记客户、对等方和地理来源的路由。此类标记通常用于控制供应商网络内及其客户和对等方的路由重新分配范围。社区还可用于各种其他应用程序，例如允许客户通过向其服务提供商发送适当的社区来设置属性，如LOCAL_PREF[RFC1771]。其他应用包括为各种类型的虚拟专用网络（VPN）发送信号（例如，虚拟专用LAN服务（VPLS）[VPLS]），以及为流量工程应用提供链路带宽[RFC4360]。
With the advent of large-scale BGP data collection [RV] [RIS] (and associated research), it has become clear that the geographical and topological information, as well as the relationship the provider has to the source of a route (e.g., transit, peer, or customer), carried in such communities is essential for a deeper understanding of the global routing system. This memo defines standard communities for export to BGP route collectors. These communities represent a significant part of information carried by service providers as of
随着大规模BGP数据收集[RV][RIS]（和相关研究）的出现，地理和拓扑信息以及供应商与路线来源（如运输、对等或客户）的关系变得越来越清楚，在这样的社区中进行研究对于深入了解全球路由系统至关重要。此备忘录定义了导出到BGP路由收集器的标准社区。到目前为止，这些社区代表了服务提供商提供的信息的重要部分
this writing, and as such could be useful for internal use by service providers. However, such use is beyond the scope of this memo. Finally, those involved in BGP data analysis are encouraged to verify with their data sources as to which peers implement this scheme (as there is a large amount of existing data as well as many legacy peerings).
这篇文章本身可能对服务提供商的内部使用很有用。然而，这种使用超出了本备忘录的范围。最后，鼓励参与BGP数据分析的人员与其数据源核实哪些对等方实施了该方案（因为存在大量现有数据以及许多遗留对等）。
The remainder of this memo is organized as follows. Section 2 provides the definition of terms used as well as the semantics of the communities used for BGP data collection, and Section 3 defines the corresponding encodings for RFC 1997 [RFC1997] communities. Finally, Section 4 defines the encodings for use with extended communities [RFC4360].
本备忘录的其余部分组织如下。第2节提供了用于BGP数据收集的术语定义以及社区语义，第3节定义了RFC 1997[RFC1997]社区的相应编码。最后，第4节定义了用于扩展社区的编码[RFC4360]。
In this section, we define the terms used and the categories of routes that may be tagged with communities. This tagging is often referred to as coloring, and we refer to a route's "color" as its community value. The categories defined here are loosely modeled on those described in [WANG] and [HUSTON].
在本节中，我们将定义使用的术语以及可能标记为社区的路线类别。这种标记通常称为着色，我们将路线的“颜色”称为其社区值。这里定义的类别是在[WANG]和[HUSTON]中描述的类别的基础上松散建模的。
Consider two network service providers, A and B. Service providers A and B are defined to be peers when (i) A and B exchange routes via BGP, and (ii) traffic exchange between A and B is settlement-free. This arrangement is also typically known as "peering". Peers typically exchange only their respective customer routes (see "Customer Routes" below), and hence exchange only their respective customer traffic. See [HUSTON] for a more in-depth discussion of the business models surrounding peers and peering.
考虑两个网络服务提供商A和B。当（I）A和B通过BGP交换路由时，服务提供商A和B被定义为对等体，以及（ii）A和B之间的流量交换是无结算的。这种安排通常也称为“对等”。对等方通常只交换各自的客户路线（请参见下面的“客户路线”），因此只交换各自的客户流量。请参见[HUSTON]，了解有关对等和对等的商业模式的更深入的讨论。
Customer routes are those routes that are heard from a customer via BGP and are propagated to peers and other customers. Note that a customer can be an enterprise or another network service provider. These routes are sometimes called client routes [HUSTON].
客户路由是通过BGP从客户那里听到并传播给对等方和其他客户的路由。请注意，客户可以是企业或其他网络服务提供商。这些路由有时称为客户端路由[HUSTON]。
Peer routes are those routes heard from peers via BGP, and not propagated to other peers. In particular, these routes are only propagated to the service provider's customers.
对等路由是指通过BGP从对等方听到的、不会传播到其他对等方的路由。特别是，这些路由仅传播给服务提供商的客户。
Internal routes are those routes that a service provider originates and passes to its peers and customers. These routes are frequently taken out of the address space allocated to a provider.
内部路由是服务提供商发起并传递给其对等方和客户的路由。这些路由经常从分配给提供者的地址空间中取出。
Internal more specific routes are those routes that are frequently used for circuit load balancing purposes and Interior Gateway Protocol (IGP) route reduction. They also may correspond to customer services that are not visible outside the service provider's network. Internal more specific routes are not exported to any external peer.
内部更具体的路由是那些经常用于电路负载平衡和内部网关协议（IGP）路由减少的路由。它们还可能对应于服务提供商网络之外不可见的客户服务。内部更具体的路由不会导出到任何外部对等方。
Special purpose routes are those routes that do not fall into any of the other classes described here. In those cases in which such routes need to be distinguished, a service provider may color such routes with a unique value. Examples of special purpose routes include anycast routes and routes for overlay networks.
特殊用途路线是指不属于此处所述任何其他类别的路线。在需要区分这些路由的情况下，服务提供商可以使用唯一值为这些路由着色。特殊用途路由的示例包括选播路由和覆盖网络路由。
Upstream routes are typically learned from an upstream service provider as part of a transit service contract executed with the upstream provider.
作为与上游服务提供商签订的运输服务合同的一部分，通常从上游服务提供商处了解上游路线。
These are route sets that are sourced from and/or received within a particular country.
这些是来源于特定国家/地区和/或在特定国家/地区内接收的路线集。
Several global backbones implement regional policy based on their deployed footprint and on strategic and business imperatives. Service providers often have settlement-free interconnections with an Autonomous System (AS) in one region, and that same AS is a customer in another region. This mandates use of regional routing, including community attributes set by the network in question to allow easy discrimination among regional routes. For example, service providers may treat a route set received from another service provider in Europe differently than the same route set received in North America, as it is common practice to sell transit in one region while peering in the other.
几个全球骨干企业根据其部署的足迹以及战略和业务需求实施区域政策。服务提供商通常与一个地区的自治系统（AS）以及另一地区的客户进行免结算互连。这就要求使用区域路由，包括由相关网络设置的社区属性，以便于在区域路由之间进行区分。例如，服务提供商可能会将从欧洲的另一个服务提供商收到的路由集与在北美收到的相同路由集区别对待，因为通常的做法是在一个地区销售公交，而在另一个地区进行窥视。
In this section, we provide RFC 1997 [RFC1997] community values for the categories described above. RFC 1997 communities are encoded as BGP Type Code 8, and are treated as 32-bit values ranging from 0x0000000 through 0xFFFFFFF. The values 0x0000000 through 0x0000FFFF and 0xFFFF0000 through 0xFFFFFFFF are reserved.
在本节中，我们为上述类别提供RFC 1997[RFC1997]社区值。RFC 1997社区编码为BGP类型代码8，并被视为范围从0x0000000到0xFFFFF的32位值。保留值0x0000000到0x0000FFFF和0xFFFF0000到0xFFFFFF。
The best current practice among service providers is to use the high-order two octets to represent the provider's AS number, and the low-order two octets to represent the classification of the route, as depicted below:
服务提供商目前的最佳实践是使用高阶两个八位字节表示提供商的AS编号，低阶两个八位字节表示路由分类，如下所示：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| <AS> | <Value> |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| <AS> | <Value> |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where <AS> is the 16-bit AS number. For example, the encoding 0x2A7C029A would represent the AS 10876 with value 666.
其中<AS>是16位AS数。例如，编码0x2A7C029A将表示值为666的AS 10876。
In this section, we define the RFC 1997 community encoding for the route types described above for use in BGP data collection. It is anticipated that a service provider's internal community values will be converted to these standard values for output to a route collector.
在本节中，我们为上述路由类型定义RFC 1997社区编码，以用于BGP数据收集。预计服务提供商的内部社区值将转换为这些标准值，以便输出到路由收集器。
This memo follows the best current practice of using the basic format <AS>:<Value>. The values for the route categories are described in the following table:
本备忘录遵循当前使用基本格式<AS>：<Value>的最佳实践。下表中描述了路线类别的值：
Category Value
===============================================================
Reserved <AS>:0000000000000000
Customer Routes <AS>:0000000000000001
Peer Routes <AS>:0000000000000010
Internal Routes <AS>:0000000000000011
Internal More Specific Routes <AS>:0000000000000100
Special Purpose Routes <AS>:0000000000000101
Upstream Routes <AS>:0000000000000110
Reserved <AS>:0000000000000111-
<AS>:0000011111111111
National and Regional Routes <AS>:0000100000000000-
<AS>:1111111111111111
Encoded as <AS>:<R><X><CC>
Reserved National and Regional values <AS>:0100000000000000-
<AS>:1111111111111111
Category Value
===============================================================
Reserved <AS>:0000000000000000
Customer Routes <AS>:0000000000000001
Peer Routes <AS>:0000000000000010
Internal Routes <AS>:0000000000000011
Internal More Specific Routes <AS>:0000000000000100
Special Purpose Routes <AS>:0000000000000101
Upstream Routes <AS>:0000000000000110
Reserved <AS>:0000000000000111-
<AS>:0000011111111111
National and Regional Routes <AS>:0000100000000000-
<AS>:1111111111111111
Encoded as <AS>:<R><X><CC>
Reserved National and Regional values <AS>:0100000000000000-
<AS>:1111111111111111
Where
哪里
<AS> is the 16-bit AS
<R> is the 5-bit Region Identifier
<X> is the 1-bit satellite link indication
X = 1 for satellite links, 0 otherwise
<CC> is the 10-bit ISO-3166-2 country code [ISO3166]
<AS> is the 16-bit AS
<R> is the 5-bit Region Identifier
<X> is the 1-bit satellite link indication
X = 1 for satellite links, 0 otherwise
<CC> is the 10-bit ISO-3166-2 country code [ISO3166]
and <R> takes the values:
和<R>取以下值：
Africa (AF) 00001 Oceania (OC) 00010 Asia (AS) 00011 Antarctica (AQ) 00100 Europe (EU) 00101 Latin America/Caribbean Islands (LAC) 00110 North America (NA) 00111 Reserved 01000-11111
非洲（AF）00001大洋洲（OC）00010亚洲（AS）00011南极洲（AQ）00100欧洲（EU）00101拉丁美洲/加勒比群岛（LAC）00110北美（NA）00111保留01000-11111
That is:
即:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| <AS> | <R> |X| <CC> |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| <AS> | <R> |X| <CC> |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For example, the encoding for a national route over a terrestrial link in AS 10876 from the Fiji Islands would be:
例如，来自斐济群岛的AS 10876中陆地链路上的国家路线编码为：
<AS> = 10876 = 0x2A7C
<R> = 00010
<X> = 0
<CC> = Fiji Islands Country Code = 242 = 0011110010
<AS> = 10876 = 0x2A7C
<R> = 00010
<X> = 0
<CC> = Fiji Islands Country Code = 242 = 0011110010
In this case, the low-order 16 bits are 0001000011110010 = 0x10F2.
在这种情况下，低阶16位为0001000011110010=0x10F2。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x2A7C | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x2A7C | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that a configuration language might allow the specification of this community as 10876:4338 (0x10F2 == 4338 decimal).
请注意，配置语言可能允许将此社区的规范设置为10876:4338（0x10F2==4338十进制）。
Finally, note that these categories are not intended to be mutually exclusive, and multiple communities can be attached where appropriate.
最后，请注意，这些类别并不打算相互排斥，可以在适当的情况下附加多个社区。
In some cases, the values and their encoding described in Section 4 may clash with a service provider's existing community assignments. Extended communities [RFC4360] provide a convenient mechanism that can be used to avoid such clashes.
在某些情况下，第4节中描述的值及其编码可能与服务提供商的现有社区分配冲突。扩展社区[RFC4360]提供了一种方便的机制，可用于避免此类冲突。
The Extended Communities attribute is a transitive optional BGP attribute with the Type Code 16 and consists of a set of extended communities of the following format:
扩展社区属性是一个可传递的可选BGP属性，类型代码为16，由一组以下格式的扩展社区组成：
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 high | Type low(*) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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 high | Type low(*) | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Value |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For purposes of BGP data collection, we encode the communities described in Section 4 using the two-octet AS specific extended community type, which has the following format:
为了收集BGP数据，我们使用两个八位组作为特定的扩展社区类型对第4节中描述的社区进行编码，其格式如下：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | Sub-Type | Global Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | Sub-Type | Global Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The two-octet AS specific extended community attribute encodes the service provider's two-octet Autonomous System number (as assigned by a Regional Internet Registry, or RIR) in the Global Administrator field, and the Local Administrator field may encode any information.
两个八位字节作为特定的扩展社区属性在全局管理员字段中编码服务提供商的两个八位字节自治系统编号（由区域互联网注册中心或RIR分配），而本地管理员字段可以编码任何信息。
This memo assigns Sub-Type 0x0008 for BGP data collection, and specifies that the <Value> field, as defined in Section 3.1, is carried in the low-order octets of the Local Administrator field. The two high-order octets of the Local Administrator field are reserved, and are set to 0x00 when sending and ignored upon receipt.
本备忘录为BGP数据采集分配子类型0x0008，并指定第3.1节中定义的<Value>字段在本地管理员字段的低位八位字节中携带。本地管理员字段的两个高阶八位字节是保留的，发送时设置为0x00，接收时忽略。
For example, the extended community encoding for 10876:4338 (representing a terrestrial national route in AS 10876 from the Fiji Islands) would be:
例如，10876:4338（代表AS 10876中从斐济群岛出发的陆地国家路线）的扩展社区编码为：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0x0008 | 0x2A7C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0x00 | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0x0008 | 0x2A7C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x00 | 0x00 | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The four-octet AS specific extended community is encoded as follows:
作为特定扩展社区的四个八位组编码如下：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x02 | 0x0008 | Global Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Global Administrator (cont.) | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x02 | 0x0008 | Global Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Global Administrator (cont.) | 0x10F2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In this case, the four-octet Global Administrator sub-field contains a four-octet Autonomous System number assigned by the IANA.
在这种情况下，四个八位字节的全局管理员子字段包含由IANA分配的四个八位字节的自治系统编号。
Note that data collection communities have the potential of making the attribute set of a specific route more unique than it would be otherwise (since each route collects data that is specific to its path inside one or more ASes). This, in turn, can affect whether multiple routes can be grouped in the same BGP update message, and it may lead to increased use of bandwidth, router CPU cycles, and memory.
请注意，数据收集社区有可能使特定路由的属性集比其他情况下更独特（因为每个路由收集一个或多个ASE中特定于其路径的数据）。这反过来会影响多条路由是否可以在同一BGP更新消息中分组，并可能导致带宽、路由器CPU周期和内存的使用增加。
The community encoding described in this memo germinated from an interesting suggestion from Akira Kato at WIDE. In particular, the idea would be to use the collection community values to select paths that would result in (hopefully) more efficient access to various services. For example, in the case of RFC 3258 [RFC3258] based DNS anycast service, BGP routers may see multiple paths to the same prefix, and others might be coming from the same origin with different paths, but others might be from different region/country (with the same origin AS).
本备忘录中描述的社区编码源于广域网的加藤明（Akira Kato）的一个有趣建议。特别是，我们的想法是使用集合社区值来选择路径，从而（希望）更高效地访问各种服务。例如，在基于RFC 3258[RFC3258]的DNS选播服务的情况下，BGP路由器可能会看到指向同一前缀的多条路径，其他路由器可能来自具有不同路径的同一来源，但其他路由器可能来自不同的地区/国家（与相同来源）。
Joe Abley, Randy Bush, Sean Donelan, Xenofontas Dimitropoulos, Vijay Gill, John Heasley, Geoff Huston, Steve Huter, Michael Patton, Olivier Marce, Ryan McDowell, Rob Rockell, Rob Thomas, Pekka Savola, Patrick Verkaik, and Alex Zinin all made many insightful comments on early versions of this document. Henk Uijterwaal suggested the use of the ISO-3166-2 country codes.
Joe Abley、Randy Bush、Sean Donelan、Xenofontas Dimitropoulos、Vijay Gill、John Heasley、Geoff Huston、Steve Huter、Michael Patton、Olivier Marce、Ryan McDowell、Rob Rockell、Rob Thomas、Pekka Savola、Patrick Verkaik和Alex Zinin都对该文件的早期版本发表了许多有见地的评论。Henk Uijterwaal建议使用ISO-3166-2国家代码。
While this memo introduces no additional security considerations into the BGP protocol, the information contained in the communities defined in this memo may in some cases reveal network structure that was not previously visible outside the provider's network. As a result, care should be taken when exporting such communities to route collectors. Finally, routes exported to a route collector should also be tagged with the NO_EXPORT community (0xFFFFFF01).
虽然本备忘录没有在BGP协议中引入额外的安全注意事项，但在某些情况下，本备忘录中定义的社区中包含的信息可能会揭示以前在提供商网络之外不可见的网络结构。因此，在将此类社区导出到路线收集器时应小心。最后，导出到路由采集器的路由还应使用NO_导出社区（0xFFFF01）进行标记。
The communities described in this memo are intended for use on egress to a route collector. Hence an operator may choose to overwrite its internal communities with the values specified in this memo when exporting routes to a route collector. However, operators should in general ensure that the behavior of their BGP implementation is well-defined when the addition of an attribute causes a PDU to exceed 4096 octets. For example, since it is common practice to use community attributes to implement policy (among other functionality such as allowing customers to set attributes such as LOCAL_PREF), the behavior of an implementation when the attribute space overflows is crucial. Among other behaviors, an implementation might usurp the intended attribute data or otherwise cause indeterminate failures. These behaviors can result in unanticipated community attribute sets, and hence result in unintended policy implications.
本备忘录中描述的社区用于路线收集器出口。因此，当将路线导出到路线收集器时，操作员可以选择使用此备忘录中指定的值覆盖其内部社区。但是，当添加属性导致PDU超过4096个八位字节时，操作员通常应确保其BGP实现的行为得到良好定义。例如，由于使用社区属性来实现策略（以及允许客户设置属性（如LOCAL_PREF））是常见的做法，因此属性空间溢出时实现的行为至关重要。在其他行为中，实现可能会篡夺预期的属性数据或导致不确定的故障。这些行为可能导致意外的社区属性集，从而导致意外的策略影响。
This memo assigns a new Sub-Type for the AS specific extended community type in the First Come First Served extended transitive category. The IANA has assigned Sub-Type 0x0008 as defined in Section 4.1.
此备忘录为“先到先得”扩展传递类别中的特定于AS的扩展社区类型分配新的子类型。IANA已分配第4.1节中定义的子类型0x0008。
In addition, the IANA has created two registries for BGP Data Collection Communities, one for standard communities and one for extended communities. Both of these registries will initially be populated by the values described in Section 4. IETF Consensus, as described in [RFC2434], usually through the Global Routing Operations Working Group (grow), is required for the assignment of new values in these registries (in particular, for <Value> or <R> in the table of values for the route categories in Section 4).
此外，IANA还为BGP数据收集社区创建了两个注册中心，一个用于标准社区，另一个用于扩展社区。这两个注册表最初将由第4节中描述的值填充。如[RFC2434]所述，通常通过全球路由操作工作组（grow）达成IETF共识，以分配这些注册表中的新值（尤其是第4节路由类别值表中的<Value>或<R>）。
[ISO3166] "ISO 3166 Maintenance agency (ISO 3166/MA)", Web Page: http://www.iso.org/iso/en/prods-services/ iso3166ma/index.html, 2004.
[ISO3166]“ISO 3166维护机构（ISO 3166/MA）”，网页：http://www.iso.org/iso/en/prods-services/ iso3166ma/index.html，2004年。
[RFC1771] Rekhter, Y. and T. Li (Editors), "A Border Gateway Protocol (BGP-4)", RFC 1771, March 1995.
[RFC1771]Rekhter，Y.和T.Li（编辑），“边界网关协议（BGP-4）”，RFC 17711995年3月。
[RFC1997] Chandra, R. and P. Traina, "BGP Communities Attribute", RFC 1997, August 1996.
[RFC1997]Chandra，R.和P.Traina，“BGP社区属性”，RFC 1997，1996年8月。
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, January 2006.
[RFC4360]Sangli，S.，Tappan，D.和Y.Rekhter，“BGP扩展社区属性”，RFC 4360，2006年1月。
[HUSTON] Huston, G., "Interconnection, Peering, and
Settlements",
http://www.isoc.org/inet99/proceedings/1e/1e_1.htm
[HUSTON] Huston, G., "Interconnection, Peering, and
Settlements",
http://www.isoc.org/inet99/proceedings/1e/1e_1.htm
[RFC2434] Narten, T., and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
[RFC2434]Narten，T.和H.Alvestrand，“在RFCs中编写IANA注意事项部分的指南”，BCP 26，RFC 2434，1998年10月。
[RFC3258] Hardie, T., "Distributing Authoritative Name Servers via Shared Unicast Addresses", RFC 3258, April 2002.
[RFC3258]Hardie，T.，“通过共享单播地址分发权威名称服务器”，RFC 3258，2002年4月。
[RIS] "The RIPE Routing Information Service", Web Page: http://www.ripe.net/ris, 2004.
[RIS]“成熟的路由信息服务”，网页：http://www.ripe.net/ris, 2004.
[RV] Meyer, D., "The Routeviews Project", Web Page: http://www.routeviews.org, 2002.
[RV]Meyer，D.，“Routeviews项目”，网页：http://www.routeviews.org, 2002.
[VPLS] Kompella, K., et al., "Virtual Private LAN Service", Work in Progress, April 2005.
[VPLS]Kompella，K.等人，“虚拟专用局域网服务”，正在进行的工作，2005年4月。
[WANG] Wang, F. and L. Gao, "Inferring and Characterizing Internet Routing Policies", ACM SIGCOMM Internet Measurement Conference 2003.
[WANG]WANG，F.和L.Gao，“推断和描述互联网路由策略”，2003年ACM SIGCOMM互联网测量会议。
Author's Address
作者地址
David Meyer
大卫·梅耶尔
EMail: dmm@1-4-5.net
EMail: dmm@1-4-5.net
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