Internet Engineering Task Force (IETF) E. Chen, Ed.
Request for Comments: 7606 Cisco Systems, Inc.
Updates: 1997, 4271, 4360, 4456, 4760, J. Scudder, Ed.
5543, 5701, 6368 Juniper Networks
Category: Standards Track P. Mohapatra
ISSN: 2070-1721 Sproute Networks
K. Patel
Cisco Systems, Inc.
August 2015
Revised Error Handling for BGP UPDATE Messages
修订后的 BGP UPDATE 报文错误处理方法
Abstract
摘要
According to the base BGP specification, a BGP speaker that receives an UPDATE message containing a malformed attribute is required to reset the session over which the offending attribute was received. This behavior is undesirable because a session reset would impact not only routes with the offending attribute but also other valid routes exchanged over the session. This document partially revises the error handling for UPDATE messages and provides guidelines for the authors of documents defining new attributes. Finally, it revises the error handling procedures for a number of existing attributes.
根据基本 BGP 规范，收到包含畸形属性的 UPDATE 消息的 BGP 说话者必须重置收到违规属性的会话。这种行为是不可取的，因为会话重置不仅会影响带有违规属性的路由，还会影响通过会话交换的其他有效路由。本文档部分修订了 UPDATE 消息的错误处理，并为定义新属性的文档作者提供了指导。最后，它还修订了一些现有属性的错误处理程序。
This document updates error handling for RFCs 1997, 4271, 4360, 4456, 4760, 5543, 5701, and 6368.
本文件更新了 RFC 1997、4271、4360、4456、4760、5543、5701 和 6368 的错误处理。
Status of This Memo
本备忘录的地位
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 5741.
本文件是互联网工程任务组 (IETF) 的成果。它代表了 IETF 社区的共识。它已接受公众审查，并经互联网工程指导小组 (IESG) 批准发布。有关互联网标准的更多信息，请参见 RFC 5741 第 2 节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7606.
有关本文件的当前状态、任何勘误以及如何提供反馈的信息，请访问 http://www.rfc-editor.org/info/rfc7606。
Copyright Notice
版权声明
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有 (c) 2015 IETF 信托基金会和文件作者。保留所有权利。
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.
本文档受 BCP 78 和本文档发布之日有效的 IETF 信托基金《与 IETF 文档有关的法律规定》 (http://trustee.ietf.org/license-info) 的约束。请仔细阅读这些文件，因为它们描述了您对本文档的权利和限制。从本文档中提取的代码组件必须包含信托法律条款第 4.e 节所述的简化 BSD 许可文本，并且按照简化 BSD 许可的规定提供，但不提供担保。
This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.
本文档可能包含 2008 年 11 月 10 日之前发布或公开的 IETF 文档或 IETF 贡献中的材料。其中某些材料的版权控制人可能未授予 IETF 托管机构允许在 IETF 标准流程之外修改这些材料的权利。如果未从此类材料的版权控制人处获得适当许可，则不得在 IETF 标准流程之外修改本文档，也不得在 IETF 标准流程之外创作本文档的衍生作品，除非将其格式化为 RFC 发布或翻译成英语以外的语言。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Error-Handling Approaches . . . . . . . . . . . . . . . . . . 5
3. Revision to BGP UPDATE Message Error Handling . . . . . . . . 5
4. Attribute Length Fields . . . . . . . . . . . . . . . . . . . 7
5. Parsing of Network Layer Reachability Information (NLRI)
Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Encoding NLRI . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Missing NLRI . . . . . . . . . . . . . . . . . . . . . . 8
5.3. Syntactic Correctness of NLRI Fields . . . . . . . . . . 9
5.4. Typed NLRI . . . . . . . . . . . . . . . . . . . . . . . 9
6. Operational Considerations . . . . . . . . . . . . . . . . . 10
7. Error-Handling Procedures for Existing Attributes . . . . . . 11
7.1. ORIGIN . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2. AS_PATH . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.3. NEXT_HOP . . . . . . . . . . . . . . . . . . . . . . . . 12
7.4. MULTI_EXIT_DISC . . . . . . . . . . . . . . . . . . . . . 12
7.5. LOCAL_PREF . . . . . . . . . . . . . . . . . . . . . . . 12
7.6. ATOMIC_AGGREGATE . . . . . . . . . . . . . . . . . . . . 12
7.7. AGGREGATOR . . . . . . . . . . . . . . . . . . . . . . . 13
7.8. Community . . . . . . . . . . . . . . . . . . . . . . . . 13
7.9. ORIGINATOR_ID . . . . . . . . . . . . . . . . . . . . . . 13
7.10. CLUSTER_LIST . . . . . . . . . . . . . . . . . . . . . . 13
7.11. MP_REACH_NLRI . . . . . . . . . . . . . . . . . . . . . . 14
7.12. MP_UNREACH_NLRI . . . . . . . . . . . . . . . . . . . . . 14
7.13. Traffic Engineering Path Attribute . . . . . . . . . . . 14
7.14. Extended Community . . . . . . . . . . . . . . . . . . . 14
7.15. IPv6 Address Specific BGP Extended Community Attribute . 15
7.16. ATTR_SET . . . . . . . . . . . . . . . . . . . . . . . . 15
8. Guidance for Authors of BGP Specifications . . . . . . . . . 15
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . 18
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
According to the base BGP specification [RFC4271], a BGP speaker that receives an UPDATE message containing a malformed attribute is required to reset the session over which the offending attribute was received. This behavior is undesirable because a session reset impacts not only routes with the offending attribute but also other valid routes exchanged over the session. In the case of optional transitive attributes, the behavior is especially troublesome and may present a potential security vulnerability. This is because attributes may have been propagated without being checked by intermediate routers that don't recognize the attributes. In effect, the attributes may have been tunneled; when they reach a router that recognizes and checks the attributes, the session that is reset may not be associated with the router that is at fault. To make matters worse, in such cases, although the problematic attributes may have originated with a single update transmitted by a single BGP speaker, by the time they encounter a router that checks them they may have been replicated many times and thus may cause the reset of many peering sessions. Thus, the damage inflicted may be multiplied manyfold.
根据基本 BGP 规范 [RFC4271]，收到包含畸形属性的 UPDATE 消息的 BGP 说话者必须重置收到违规属性的会话。这种行为是不可取的，因为会话重置不仅会影响带有违规属性的路由，还会影响通过会话交换的其他有效路由。对于可选的传递属性，这种行为尤其麻烦，可能会带来潜在的安全漏洞。这是因为，中间路由器可能在未检查属性的情况下传播了属性，而中间路由器并不识别这些属性。实际上，这些属性可能已被隧道传输；当它们到达能识别并检查属性的路由器时，被重置的会话可能与出错的路由器无关。更糟糕的是，在这种情况下，尽管有问题的属性可能是由单个 BGP 发言者传输的单个更新产生的，但当它们遇到检查它们的路由器时，它们可能已经被复制了很多次，因此可能导致许多对等会话重置。因此，造成的损失可能会成倍增加。
The goal for revising the error handling for UPDATE messages is to minimize the impact on routing by a malformed UPDATE message while maintaining protocol correctness to the extent possible. This can be achieved largely by maintaining the established session and keeping the valid routes exchanged but removing the routes carried in the malformed UPDATE message from the routing system.
修订 UPDATE 报文错误处理的目标是，在尽可能保持协议正确性的同时，尽量减少畸形 UPDATE 报文对路由选择的影响。要做到这一点，主要是维持已建立的会话，保留已交换的有效路由，但从路由系统中删除畸形 UPDATE 报文中携带的路由。
This document partially revises the error handling for UPDATE messages and provides guidelines for the authors of documents defining new attributes. Finally, it revises the error handling procedures for a number of existing attributes. Specifically, the error handling procedures of [RFC1997], [RFC4271], [RFC4360], [RFC4456], [RFC4760], [RFC5543], [RFC5701], and [RFC6368] are revised.
本文件部分修订了 UPDATE 消息的错误处理，并为定义新属性的文件编写者提供了指导。最后，它还修订了一些现有属性的错误处理程序。特别是修订了 [RFC1997]、[RFC4271]、[RFC4360]、[RFC4456]、[RFC4760]、[RFC5543]、[RFC5701] 和 [RFC6368] 的错误处理程序。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
本文档中的关键词 "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", 以及 "OPTIONAL" 应按照RFC 2119 [RFC2119]中的描述进行解释。
In this document, we refer to four different approaches to handle errors found in a BGP UPDATE message. They are as follows (listed in order, from the one with the "strongest" action to the one with the "weakest" action):
在本文档中，我们提到了处理 BGP UPDATE 消息中发现的错误的四种不同方法。它们分别如下（按从 "最强 "操作到 "最弱 "操作的顺序排列）：
o Session reset: This is the approach used throughout the base BGP specification [RFC4271], where a NOTIFICATION is sent and the session terminated.
o 会话重置：这是整个基本 BGP 规范 [RFC4271] 中使用的方法，即发送通知并终止会话。
o AFI/SAFI disable: Section 7 of [RFC4760] allows a BGP speaker that detects an error in a message for a given AFI/SAFI to optionally "ignore all the subsequent routes with that AFI/SAFI received over that session". We refer to this as "disabling a particular AFI/ SAFI" or "AFI/SAFI disable".
o 禁用 AFI/SAFI：RFC4760] 第 7 节允许 BGP 发言者在检测到给定 AFI/SAFI 消息中的错误时，可选择 "忽略在该会话中收到的带有该 AFI/SAFI 的所有后续路由"。我们称之为 "禁用特定 AFI/SAFI "或 "禁用 AFI/SAFI"。
o Treat-as-withdraw: In this approach, the UPDATE message containing the path attribute in question MUST be treated as though all contained routes had been withdrawn just as if they had been listed in the WITHDRAWN ROUTES field (or in the MP_UNREACH_NLRI attribute if appropriate) of the UPDATE message, thus causing them to be removed from the Adj-RIB-In according to the procedures of [RFC4271].
o 视同撤回：在这种方法中，包含相关路径属性的 UPDATE 消息必须被视为所有包含的路由已被撤销，就像它们已被列在 UPDATE 消息的 WITHDRAWN ROUTES 字段（或 MP_UNREACH_NLRI 属性（如适用））中一样，从而导致它们根据 [RFC4271] 的程序从 Adj-RIB-In 中删除。
o Attribute discard: In this approach, the malformed attribute MUST be discarded and the UPDATE message continues to be processed. This approach MUST NOT be used except in the case of an attribute that has no effect on route selection or installation.
o 属性丢弃：在这种方法中，必须丢弃畸形属性，并继续处理 UPDATE 消息。除非属性对路由选择或安装没有影响，否则不得使用这种方法。
This specification amends Section 6.3 of [RFC4271] in a number of ways. See Section 7 for treatment of specific path attributes.
本规范以多种方式对 [RFC4271] 第 6.3 节进行了修订。有关特定路径属性的处理，请参见第 7 节。
a. The first paragraph is revised as follows:
a. 第一段修改如下
Old Text:
旧文本：
All errors detected while processing the UPDATE message MUST be indicated by sending the NOTIFICATION message with the Error Code UPDATE Message Error. The error subcode elaborates on the specific nature of the error.
处理 UPDATE 报文时检测到的所有错误必须通过发送带有错误代码 UPDATE 报文错误的通知报文来说明。错误子代码详细说明了错误的具体性质。
New Text:
新文本：
An error detected while processing the UPDATE message for which a session reset is specified MUST be indicated by sending the NOTIFICATION message with the Error Code UPDATE Message Error. The error subcode elaborates on the specific nature of the error.
如果在处理 UPDATE 报文时检测到错误，并为此指定了会话重置，则必须发送带有错误代码 UPDATE 报文错误的通知报文。错误子代码详细说明了错误的具体性质。
b. Error handling for the following case remains unchanged:
b. 以下情况的错误处理保持不变：
If the Withdrawn Routes Length or Total Attribute Length is too large (i.e., if Withdrawn Routes Length + Total Attribute Length + 23 exceeds the message Length), then the Error Subcode MUST be set to Malformed Attribute List.
如果撤回的路由长度或总属性长度过大（即撤回的路由长度 + 总属性长度 + 23 超过报文长度），则错误子码必须设置为畸形属性列表。
c. Attribute Flag error handling is revised as follows:
c. 属性标志错误处理修改如下：
Old Text:
旧文本：
If any recognized attribute has Attribute Flags that conflict with the Attribute Type Code, then the Error Subcode MUST be set to Attribute Flags Error. The Data field MUST contain the erroneous attribute (type, length, and value).
如果任何已识别属性的属性标志（Attribute Flags）与属性类型代码（Attribute Type Code）相冲突，则错误子代码必须设置为属性标志错误（Attribute Flags Error）。数据字段必须包含错误属性（类型、长度和值）。
New Text:
新文本：
If the value of either the Optional or Transitive bits in the Attribute Flags is in conflict with their specified values, then the attribute MUST be treated as malformed and the "treat-as-withdraw" approach used, unless the specification for the attribute mandates different handling for incorrect Attribute Flags.
如果属性标志（Attribute Flags）中的可选位或传递位的值与指定值相冲突，则必须将该属性视为畸形属性并采用 "视为撤回 "的方法，除非该属性的规范规定对不正确的属性标志（Attribute Flags）进行不同的处理。
d. If any of the well-known mandatory attributes are not present in an UPDATE message, then "treat-as-withdraw" MUST be used. (Note that [RFC4760] reclassifies NEXT_HOP as what is effectively discretionary.)
d. 如果 UPDATE 消息中不存在任何众所周知的强制属性，则必须使用 "视作撤回"（treat-as-withdraw）。(请注意，[RFC4760] 将 NEXT_HOP 重新归类为有效的自由裁量属性）。
e. "Treat-as-withdraw" MUST be used for the cases that specify a session reset and involve any of the attributes ORIGIN, AS_PATH, NEXT_HOP, MULTI_EXIT_DISC, or LOCAL_PREF.
e. 对于指定会话重置并涉及 ORIGIN、AS_PATH、NEXT_HOP、MULTI_EXIT_DISC 或 LOCAL_PREF 属性的情况，必须使用 "Treat-as-withdraw"。
f. "Attribute discard" MUST be used for any of the cases that specify a session reset and involve ATOMIC_AGGREGATE or AGGREGATOR.
f. "属性丢弃 "必须用于指定会话重置并涉及 ATOMIC_AGGREGATE 或 AGGREGATOR 的任何情况。
g. If the MP_REACH_NLRI attribute or the MP_UNREACH_NLRI [RFC4760] attribute appears more than once in the UPDATE message, then a NOTIFICATION message MUST be sent with the Error Subcode "Malformed Attribute List". If any other attribute (whether recognized or unrecognized) appears more than once in an UPDATE message, then all the occurrences of the attribute other than the first one SHALL be discarded and the UPDATE message will continue to be processed.
g. 如果 MP_REACH_NLRI 属性或 MP_UNREACH_NLRI [RFC4760] 属性在 UPDATE 报文中出现一次以上，则必须发送带有错误子代码 "畸形属性列表 "的通知报文。如果任何其他属性（无论是已识别还是未识别）在 UPDATE 报文中出现超过一次，则除第一个属性外的所有其他属性都将被丢弃，UPDATE 报文将继续被处理。
h. When multiple attribute errors exist in an UPDATE message, if the same approach (as described in Section 2) is specified for the handling of these malformed attributes, then the specified approach MUST be used. Otherwise, the approach with the strongest action MUST be used.
h. 当 UPDATE 消息中存在多个属性错误时，如果为处理这些畸形属性指定了相同的方法（如第 2 节所述），则必须使用指定的方法。否则，必须使用作用最强的方法。
i. The Withdrawn Routes field MUST be checked for syntactic correctness in the same manner as the NLRI field. This is discussed further below and in Section 5.3.
i. 必须以与 NLRI 字段相同的方式检查撤消路由字段的语法正确性。下文和第 5.3 节将对此作进一步讨论。
j. Finally, we observe that in order to use the approach of "treat-as-withdraw", the entire NLRI field and/or the MP_REACH_NLRI and MP_UNREACH_NLRI attributes need to be successfully parsed -- what this entails is discussed in more detail in Section 5. If this is not possible, the procedures of [RFC4271] and/or [RFC4760] continue to apply, meaning that the "session reset" approach (or the "AFI/SAFI disable" approach) MUST be followed.
j. 最后，我们注意到，要使用 "视同撤回 "方法，就必须成功解析整个 NLRI 字段和/或 MP_REACH_NLRI 和 MP_UNREACH_NLRI 属性--第 5 节将详细讨论这一点。如果无法做到这一点，[RFC4271]和/或[RFC4760]的程序将继续适用，这意味着必须遵循 "会话重置 "方法（或 "AFI/SAFI 禁用 "方法）。
There are two error cases in which the Total Attribute Length value can be in conflict with the enclosed path attributes, which themselves carry length values:
在两种错误情况下，总属性长度值可能与所括弧的路径属性相冲突，而路径属性本身也带有长度值：
o In the first case, the length of the last encountered path attribute would cause the Total Attribute Length to be exceeded when parsing the enclosed path attributes.
o 在第一种情况下，最后遇到的路径属性的长度会导致在解析所附路径属性时超出总属性长度。
o In the second case, fewer than three octets remain (or fewer than four octets, if the Attribute Flags field has the Extended Length bit set) when beginning to parse the attribute. That is, this case exists if there remains unconsumed data in the path attributes but yet insufficient data to encode a single minimum-sized path attribute.
o 第二种情况是，在开始解析属性时，剩余的八位字节少于三个（或少于四个八位字节，如果属性标志字段设置了扩展长度位）。也就是说，如果路径属性中仍有未消耗的数据，但又没有足够的数据来编码一个最小尺寸的路径属性，就会出现这种情况。
In either of these cases, an error condition exists and the "treat-as-withdraw" approach MUST be used (unless some other, more severe error is encountered dictating a stronger approach), and the Total Attribute Length MUST be relied upon to enable the beginning of the NLRI field to be located.
在这两种情况下，都存在错误条件，必须使用 "视作撤回 "方法（除非遇到其他更严重的错误，需要使用更强的方法），并且必须依靠 "总属性长度 "来定位 NLRI 字段的开头。
For all path attributes other than those specified as having an attribute length that may be zero, it SHALL be considered a syntax error for the attribute to have a length of zero. Of the path attributes considered in this specification, only AS_PATH and ATOMIC_AGGREGATE may validly have an attribute length of zero.
对于除指定属性长度可以为零的属性以外的所有路径属性，属性长度为零将被视为语法错误。在本规范考虑的路径属性中，只有 AS_PATH 和 ATOMIC_AGGREGATE 的属性长度可以有效地为零。
To facilitate the determination of the NLRI field in an UPDATE message with a malformed attribute:
为便于确定带有畸形属性的 UPDATE 报文中的 NLRI 字段：
o The MP_REACH_NLRI or MP_UNREACH_NLRI attribute (if present) SHALL be encoded as the very first path attribute in an UPDATE message.
o MP_REACH_NLRI 或 MP_UNREACH_NLRI 属性（如果存在）应被编码为 UPDATE 报文中的第一个路径属性。
o An UPDATE message MUST NOT contain more than one of the following: non-empty Withdrawn Routes field, non-empty Network Layer Reachability Information field, MP_REACH_NLRI attribute, and MP_UNREACH_NLRI attribute.
o 更新报文不得包含以下内容中的一个以上：非空的 "撤回路由 "字段、非空的 "网络层可达性信息 "字段、MP_REACH_NLRI 属性和 MP_UNREACH_NLRI 属性。
Since older BGP speakers may not implement these restrictions, an implementation MUST still be prepared to receive these fields in any position or combination.
由于较早的 BGP 发言者可能没有实施这些限制，因此实施仍必须准备好以任何位置或组合接收这些字段。
If the encoding of [RFC4271] is used, the NLRI field for the IPv4 unicast address family is carried immediately following all the attributes in an UPDATE message. When such an UPDATE message is received, we observe that the NLRI field can be determined using the Message Length, Withdrawn Route Length, and Total Attribute Length (when they are consistent) carried in the message instead of relying on the length of individual attributes in the message.
如果使用 [RFC4271] 的编码，IPv4 单播地址族的 NLRI 字段将紧跟 UPDATE 报文中的所有属性之后。当收到这样的 UPDATE 报文时，我们发现 NLRI 字段可通过报文中的报文长度、撤回路由长度和总属性长度（当它们一致时）来确定，而不是依赖报文中各个属性的长度。
[RFC4724] specifies an End-of-RIB message (EoR) that can be encoded as an UPDATE message that contains only a MP_UNREACH_NLRI attribute that encodes no NLRI (it can also be a completely empty UPDATE message in the case of the "legacy" encoding). In all other well-specified cases, an UPDATE message either carries only withdrawn routes (either in the Withdrawn Routes field or the MP_UNREACH_NLRI attribute) or it advertises reachable routes (either in the Network Layer Reachability Information field or the MP_REACH_NLRI attribute).
[RFC4724] 规定了一种 End-of-RIB 报文 (EoR)，它可以编码为只包含 MP_UNREACH_NLRI 属性且不编码 NLRI 的 UPDATE 报文（在 "传统 "编码的情况下，它也可以是完全空的 UPDATE 报文）。在所有其他明确规定的情况下，UPDATE 报文要么只携带已撤销路由（在 "撤销路由 "字段或 MP_UNREACH_NLRI 属性中），要么宣传可到达路由（在 "网络层可达性信息 "字段或 MP_REACH_NLRI 属性中）。
Thus, if an UPDATE message is encountered that does contain path attributes other than MP_UNREACH_NLRI and doesn't encode any reachable NLRI, we cannot be confident that the NLRI have been successfully parsed as Section 3 (j) requires. For this reason, if any path attribute errors are encountered in such an UPDATE message and if any encountered error specifies an error-handling approach other than "attribute discard", then the "session reset" approach MUST be used.
因此，如果遇到的 UPDATE 报文确实包含 MP_UNREACH_NLRI 以外的路径属性，但没有编码任何可到达的 NLRI，我们就无法确信 NLRI 已按第 3 (j) 节的要求成功解析。因此，如果在此类 UPDATE 消息中遇到任何路径属性错误，并且如果遇到的任何错误指定了 "属性丢弃 "以外的错误处理方法，则必须使用 "会话重置 "方法。
The NLRI field or Withdrawn Routes field SHALL be considered "syntactically incorrect" if either of the following are true:
如果以下任一情况属实，NLRI 字段或撤销路由字段将被视为 "语法错误"：
o The length of any of the included NLRI is greater than 32.
o 所包含的任何 NLRI 长度均大于 32。
o When parsing NLRI contained in the field, the length of the last NLRI found exceeds the amount of unconsumed data remaining in the field.
o 解析字段中包含的 NLRI 时，最后找到的 NLRI 长度超过字段中剩余的未消耗数据量。
Similarly, the MP_REACH_NLRI or MP_UNREACH_NLRI attribute of an update SHALL be considered to be incorrect if any of the following are true:
同样，如果出现以下情况，更新的 MP_REACH_NLRI 或 MP_UNREACH_NLRI 属性将被视为不正确：
o The length of any of the included NLRI is inconsistent with the given AFI/SAFI (for example, if an IPv4 NLRI has a length greater than 32 or an IPv6 NLRI has a length greater than 128).
o 包含的任何 NLRI 长度与给定的 AFI/SAFI 不一致（例如，IPv4 NLRI 长度大于 32 或 IPv6 NLRI 长度大于 128）。
o When parsing NLRI contained in the attribute, the length of the last NLRI found exceeds the amount of unconsumed data remaining in the attribute.
o 解析属性中包含的 NLRI 时，最后找到的 NLRI 长度超过了属性中剩余的未消耗数据量。
o The attribute flags of the attribute are inconsistent with those specified in [RFC4760].
o 属性的属性标志与 [RFC4760] 中指定的属性标志不一致。
o The length of the MP_UNREACH_NLRI attribute is less than 3, or the length of the MP_REACH_NLRI attribute is less than 5.
o MP_UNREACH_NLRI 属性的长度小于 3，或 MP_REACH_NLRI 属性的长度小于 5。
Certain address families, for example, MCAST-VPN [RFC6514], MCAST-VPLS [RFC7117], and EVPN [RFC7432] have NLRI that are typed. Since supported type values within the address family are not expressed in the Multiprotocol BGP (MP-BGP) capability [RFC4760], it is possible for a BGP speaker to advertise support for the given address family and subaddress family while still not supporting a particular type of NLRI within that AFI/SAFI.
某些地址族（例如 MCAST-VPN [RFC6514]、MCAST-VPLS [RFC7117] 和 EVPN [RFC7432]）的 NLRI 是类型化的。由于多协议 BGP (MP-BGP) 功能 [RFC4760] 中未表达地址族中受支持的类型值，因此 BGP 发言者有可能公布对给定地址族和子地址族的支持，但仍不支持该 AFI/SAFI 中特定类型的 NLRI。
A BGP speaker advertising support for such a typed address family MUST handle routes with unrecognized NLRI types within that address family by discarding them, unless the relevant specification for that address family specifies otherwise.
除非该地址族的相关规范另有规定，否则 BGP 发言者必须通过丢弃路由来处理该地址族中未识别 NLRI 类型的路由。
Although the "treat-as-withdraw" error-handling behavior defined in Section 2 makes every effort to preserve BGP's correctness, we note that if an UPDATE message received on an Internal BGP (IBGP) session is subjected to this treatment, inconsistent routing within the affected Autonomous System may result. The consequences of inconsistent routing can include long-lived forwarding loops and black holes. While lamentable, this issue is expected to be rare in practice, and, more importantly, is seen as less problematic than the session-reset behavior it replaces.
尽管第 2 节中定义的 "视作撤回 "错误处理行为会尽力保持 BGP 的正确性，但我们注意到，如果在内部 BGP（IBGP）会话上收到的 UPDATE 消息受到这种处理，可能会导致受影响的自治系统内路由不一致。路由不一致的后果可能包括长期存在的转发循环和黑洞。这个问题虽然令人遗憾，但预计在实践中并不多见，更重要的是，它被认为比它所取代的会话重置行为问题更少。
When a malformed attribute is indeed detected over an IBGP session, we recommend that routes with the malformed attribute be identified and traced back to the ingress router in the network where the routes were sourced or received externally and then a filter be applied on the ingress router to prevent the routes from being sourced or received. This will help maintain routing consistency in the network.
如果在 IBGP 会话中确实检测到畸形属性，我们建议识别出带有畸形属性的路由，并追溯到网络中路由来源或外部接收的入口路由器，然后在入口路由器上应用过滤器，防止路由来源或接收。这将有助于保持网络中路由的一致性。
Even if inconsistent routing does not arise, the "treat-as-withdraw" behavior can cause either complete unreachability or suboptimal routing for the destinations whose routes are carried in the affected UPDATE message.
即使不会出现路由不一致的情况，"视作撤回 "行为也会导致完全不可达，或使受影响的 UPDATE 报文中包含路由的目的地的路由处于次优状态。
Note that "treat-as-withdraw" is different from discarding an UPDATE message. The latter violates the basic BGP principle of an incremental update and could cause invalid routes to be kept.
请注意，"视为撤回 "与丢弃 UPDATE 消息不同。后者违反了增量更新的基本 BGP 原则，可能导致无效路由被保留。
Because of these potential issues, a BGP speaker must provide debugging facilities to permit issues caused by a malformed attribute to be diagnosed. At a minimum, such facilities must include logging an error listing the NLRI involved and containing the entire malformed UPDATE message when such an attribute is detected. The malformed UPDATE message should be analyzed, and the root cause should be investigated.
由于存在这些潜在问题，BGP 说话者必须提供调试功能，以便诊断由畸形属性引起的问题。此类设施至少必须包括在检测到此类属性时记录错误日志，其中列出所涉及的 NLRI 并包含整个畸形 UPDATE 消息。应对畸形的 UPDATE 消息进行分析，并调查其根本原因。
Section 8 mentions that "attribute discard" should not be used in cases where "the attribute in question has or may have an effect on route selection." Although all cases that specify "attribute discard" in this document do not affect route selection by default, in principle, routing policies could be written that affect selection based on such an attribute. Operators should take care when writing such policies to consider the possible consequences of an attribute discard. In general, as long as such policies are only applied to external BGP sessions, correctness issues are not expected to arise.
第 8 节提到，在 "有关属性对路由选择有影响或可能有影响 "的情况下，不应使用 "属性丢弃"。虽然本文档中指定 "属性丢弃 "的所有情况默认情况下都不会影响路由选择，但原则上可以编写路由策略来影响基于此类属性的路由选择。操作员在编写此类策略时应注意考虑属性丢弃可能带来的后果。一般来说，只要此类策略只应用于外部 BGP 会话，就不会出现正确性问题。
In the following subsections, we elaborate on the conditions for error-checking various path attributes and specify what approach(es) should be used to handle malformations. It is possible that implementations may apply other error checks not contemplated here. If so, the error handling approach given here should generally be applied.
在下面的小节中，我们将详细说明对各种路径属性进行错误检查的条件，并具体说明应采用何种方法来处理畸形。实现可能会应用此处未考虑的其他错误检查。如果是这样，一般应采用此处给出的错误处理方法。
This section addresses all path attributes that are defined at the time of this writing that were not defined with error handling consistent with Section 8 and that are not marked as "deprecated" in the "BGP Path Attributes" registry [IANA-BGP-ATTRS]. Attributes 17 (AS4_PATH), 18 (AS4_AGGREGATOR), 22 (PMSI_TUNNEL), 23 (Tunnel Encapsulation Attribute), 26 (AIGP), 27 (PE Distinguisher Labels), and 29 (BGP-LS Attribute) do have error handling consistent with Section 8 and thus are not further discussed herein. Attributes 11 (DPA), 12 (ADVERTISER), 13 (RCID_PATH / CLUSTER_ID), 19 (SAFI Specific Attribute), 20 (Connector Attribute), 21 (AS_PATHLIMIT), and 28 (BGP Entropy Label Capability Attribute) are deprecated and thus are not further discussed herein.
本节将讨论在本文撰写时已定义的所有路径属性，这些属性未定义与第 8 节一致的错误处理，也未在 "BGP 路径属性 "注册表 [IANA-BGP-ATTRS] 中标记为 "已废弃"。属性 17 (AS4_PATH)、18 (AS4_AGGREGATOR)、22 (PMSI_TUNNEL)、23 (Tunnel Encapsulation Attribute)、26 (AIGP)、27 (PE Distinguisher Labels) 和 29 (BGP-LS Attribute) 的错误处理与第 8 节一致，因此在此不再赘述。属性 11 (DPA)、12 (ADVERTISER)、13 (RCID_PATH/CLUSTER_ID)、19 (SAFI 特定属性)、20 (连接器属性)、21 (AS_PATHLIMIT) 和 28 (BGP Entropy Label Capability Attribute) 已被弃用，因此不再在此讨论。
The attribute is considered malformed if its length is not 1 or if it has an undefined value [RFC4271].
如果属性长度不为 1 或属性值未定义，则视为畸形属性 [RFC4271]。
An UPDATE message with a malformed ORIGIN attribute SHALL be handled using the approach of "treat-as-withdraw".
对于带有畸形 ORIGIN 属性的更新报文，应采用 "视作撤回 "的方法进行处理。
An AS_PATH is considered malformed if an unrecognized segment type is encountered or if it contains a malformed segment. A segment is considered malformed if any of the following are true:
如果遇到未识别的网段类型或包含畸形网段，AS_PATH 将被视为畸形。如果以下任一情况为真，则视为畸形数据段：
o There is an overrun where the Path Segment Length field of the last segment encountered would cause the Attribute Length to be exceeded.
o 出现超限，即遇到的最后一个数据段的路径段长度字段会导致属性长度超限。
o There is an underrun where after the last successfully parsed segment there is only a single octet remaining (that is, there is not enough unconsumed data to provide even an empty segment header).
o 如果在最后一个成功解析的数据段之后只剩下一个八位位组（也就是说，没有足够的未消耗数据来提供一个空的数据段标题），就会出现数据不足的情况。
o It has a Path Segment Length field of zero.
o 它的路径段长度字段为零。
An UPDATE message with a malformed AS_PATH attribute SHALL be handled using the approach of "treat-as-withdraw".
对于带有畸形 AS_PATH 属性的 UPDATE 报文，应采用 "视为撤回 "的方法进行处理。
[RFC4271] also says that an implementation optionally "MAY check whether the leftmost ... AS in the AS_PATH attribute is equal to the autonomous system number of the peer that sent the message". A BGP implementation SHOULD also handle routes that violate this check using "treat-as-withdraw" but MAY follow the "session reset" behavior if configured to do so.
[RFC4271]还指出，实施可以选择 "检查 AS_PATH 属性中最左边的...AS_PATH 属性中最左边的 AS 是否等于发送信息的对等节点的自治系统编号"。BGP 实现也应使用 "视作撤回"（treat-as-withdraw）来处理违反此检查的路由，但如果配置了 "会话重置"（session reset）行为，则可以这样做。
The attribute is considered malformed if its length is not 4 [RFC4271].
如果属性长度不是 4 [RFC4271]，则视为畸形属性。
An UPDATE message with a malformed NEXT_HOP attribute SHALL be handled using the approach of "treat-as-withdraw".
对于带有畸形 NEXT_HOP 属性的 UPDATE 报文，应采用 "视作撤回 "的方法进行处理。
The attribute is considered malformed if its length is not 4 [RFC4271].
如果属性长度不是 4 [RFC4271]，则视为畸形属性。
An UPDATE message with a malformed MULTI_EXIT_DISC attribute SHALL be handled using the approach of "treat-as-withdraw".
对于带有畸形 MULTI_EXIT_DISC 属性的 UPDATE 报文，应采用 "视作撤回 "的方法进行处理。
The error handling of [RFC4271] is revised as follows:
RFC4271] 的错误处理修改如下：
o if the LOCAL_PREF attribute is received from an external neighbor, it SHALL be discarded using the approach of "attribute discard"; or
o 如果从外部邻居接收到 LOCAL_PREF 属性，则应使用 "属性丢弃 "方法将其丢弃；或
o if received from an internal neighbor, it SHALL be considered malformed if its length is not equal to 4. If malformed, the UPDATE message SHALL be handled using the approach of "treat-as-withdraw".
o 如果从内部邻居收到 UPDATE 报文，如果其长度不等于 4，则应视为畸形。 如果是畸形，则应使用 "视为撤回 "的方法处理 UPDATE 报文。
The attribute SHALL be considered malformed if its length is not 0 [RFC4271].
如果属性长度不为 0，则应视为畸形属性 [RFC4271]。
An UPDATE message with a malformed ATOMIC_AGGREGATE attribute SHALL be handled using the approach of "attribute discard".
对于带有畸形 ATOMIC_AGGREGATE 属性的 UPDATE 报文，应采用 "属性丢弃 "的方法进行处理。
The error conditions specified in [RFC4271] for the attribute are revised as follows:
RFC4271] 中为该属性规定的错误条件修订如下：
The AGGREGATOR attribute SHALL be considered malformed if any of the following applies:
如果出现以下情况，AGGREGATOR 属性将被视为畸形：
o Its length is not 6 (when the 4-octet AS number capability is not advertised to or not received from the peer [RFC6793]).
o 其长度不为 6（当 4 八位字节 AS 号码功能未向对等方公布或未从对等方收到时 [RFC6793]）。
o Its length is not 8 (when the 4-octet AS number capability is both advertised to and received from the peer).
o 其长度不为 8（当向对等方发布和从对等方接收 4 八位字节 AS 号能力时）。
An UPDATE message with a malformed AGGREGATOR attribute SHALL be handled using the approach of "attribute discard".
对于带有畸形 AGGREGATOR 属性的 UPDATE 报文，应采用 "属性丢弃 "的方法进行处理。
The error handling of [RFC1997] is revised as follows:
对 [RFC1997] 的错误处理修改如下：
o The Community attribute SHALL be considered malformed if its length is not a non-zero multiple of 4.
o 如果 Community 属性的长度不是 4 的非零倍数，则应将其视为畸形。
o An UPDATE message with a malformed Community attribute SHALL be handled using the approach of "treat-as-withdraw".
o 对于带有畸形 Community 属性的 UPDATE 报文，应采用 "视作撤回 "的方法进行处理。
The error handling of [RFC4456] is revised as follows:
RFC4456] 的错误处理修改如下：
o if the ORIGINATOR_ID attribute is received from an external neighbor, it SHALL be discarded using the approach of "attribute discard"; or
o 如果从外部邻居接收到 ORIGINATOR_ID 属性，则应使用 "属性丢弃 "方法将其丢弃；或
o if received from an internal neighbor, it SHALL be considered malformed if its length is not equal to 4. If malformed, the UPDATE message SHALL be handled using the approach of "treat-as-withdraw".
o 如果从内部邻居收到 UPDATE 报文，如果其长度不等于 4，则应视为畸形。 如果是畸形，则应使用 "视为撤回 "的方法处理 UPDATE 报文。
The error handling of [RFC4456] is revised as follows:
RFC4456] 的错误处理修改如下：
o if the CLUSTER_LIST attribute is received from an external neighbor, it SHALL be discarded using the approach of "attribute discard"; or
o 如果从外部邻居接收到 CLUSTER_LIST 属性，则应使用 "属性丢弃 "方法将其丢弃；或
o if received from an internal neighbor, it SHALL be considered malformed if its length is not a non-zero multiple of 4. If malformed, the UPDATE message SHALL be handled using the approach of "treat-as-withdraw".
o 如果从内部邻居收到 UPDATE 消息，如果其长度不是 4 的非零倍数，则应视为畸形。 如果是畸形，则应使用 "视为撤回 "的方法处理 UPDATE 消息。
If the Length of Next Hop Network Address field of the MP_REACH attribute is inconsistent with that which was expected, the attribute is considered malformed. Since the next hop precedes the NLRI field in the attribute, in this case it will not be possible to reliably locate the NLRI; thus, the "session reset" or "AFI/SAFI disable" approach MUST be used.
如果 MP_REACH 属性的 "下一跳网络地址长度 "字段与预期值不一致，该属性将被视为畸形。由于下一跳在属性中的 NLRI 字段之前，因此在这种情况下无法可靠地定位 NLRI；因此，必须使用 "会话重置 "或 "禁用 AFI/SAFI "方法。
"That which was expected", while somewhat vague, is intended to encompass the next hop specified for the Address Family Identifier and Subsequent Address Family Identifier fields and is potentially modified by any extensions in use. For example, if [RFC5549] is in use, then the next hop would have to have a length of 4 or 16.
"预期的 "虽然有些含糊，但其目的是包括为地址族标识符和后续地址族标识符字段指定的下一跳，并有可能根据使用中的任何扩展进行修改。例如，如果使用 [RFC5549]，那么下一跳的长度必须是 4 或 16。
Sections 3 and 5 provide further discussion of the handling of this attribute.
第 3 节和第 5 节将进一步讨论如何处理该属性。
Sections 3 and 5 discuss the handling of this attribute.
第 3 节和第 5 节将讨论如何处理该属性。
We note that [RFC5543] does not detail what constitutes "malformation" for the Traffic Engineering path attribute. A future update to that specification may provide more guidance. In the interim, an implementation that determines (for whatever reason) that an UPDATE message contains a malformed Traffic Engineering path attribute MUST handle it using the approach of "treat-as-withdraw".
我们注意到，[RFC5543] 并未详细说明何为流量工程路径属性的 "畸形"。该规范的未来更新可能会提供更多指导。在此期间，如果实施确定 UPDATE 消息包含畸形的流量工程路径属性（无论出于何种原因），则必须使用 "视为撤回 "的方法来处理。
The error handling of [RFC4360] is revised as follows:
RFC4360] 的错误处理修改如下：
o The Extended Community attribute SHALL be considered malformed if its length is not a non-zero multiple of 8.
o 如果扩展社区属性的长度不是 8 的非零整数倍，则该属性应被视为畸形。
o An UPDATE message with a malformed Extended Community attribute SHALL be handled using the approach of "treat-as-withdraw".
o 对于带有畸形 "扩展社区 "属性的更新报文，应采用 "视作撤回 "的方法进行处理。
Note that a BGP speaker MUST NOT treat an unrecognized Extended Community Type or Sub-Type as an error.
请注意，BGP 说话者不得将未识别的扩展社区类型或子类型视为错误。
The error handling of [RFC5701] is revised as follows:
RFC5701] 的错误处理修改如下：
o The IPv6 Address Specific Extended Community attribute SHALL be considered malformed if its length is not a non-zero multiple of 20.
o 如果 IPv6 特定地址扩展社区属性的长度不是 20 的非零倍数，则该属性应被视为畸形。
o An UPDATE message with a malformed IPv6 Address Specific Extended Community attribute SHALL be handled using the approach of "treat-as-withdraw".
o 对于带有畸形 IPv6 特定地址扩展社区属性的 UPDATE 报文，应采用 "视为撤回 "的方法进行处理。
Note that a BGP speaker MUST NOT treat an unrecognized IPv6 Address Specific Extended Community Type or Sub-Type as an error.
请注意，BGP 说话者不得将未识别的 IPv6 特定地址扩展社区类型或子类型视为错误。
The final paragraph of Section 5 of [RFC6368] is revised as follows:
RFC6368] 第 5 节最后一段修改如下：
Old Text:
旧文本：
An UPDATE message with a malformed ATTR_SET attribute SHALL be handled as follows. If its Partial flag is set and its Neighbor-Complete flag is clear, the UPDATE message is treated as a route withdraw as discussed in [OPT-TRANS-BGP]. Otherwise (i.e., Partial flag is clear or Neighbor-Complete is set), the procedures of the BGP-4 base specification [RFC4271] MUST be followed with respect to an Optional Attribute Error.
带有畸形 ATTR_SET 属性的 UPDATE 消息应按以下方式处理。如果 "部分 "标志被设置且 "邻居-完成 "标志被清除，则 UPDATE 消息将被视为路由撤销，如 [OPT-TRANS-BGP] 所述。否则（即 "部分 "标志被清除或 "邻居-完整 "标志被设置），必须遵循 BGP-4 基本规范 [RFC4271] 中有关可选属性错误的程序。
New Text:
新文本：
An UPDATE message with a malformed ATTR_SET attribute SHALL be handled using the approach of "treat as withdraw".
对于带有畸形 ATTR_SET 属性的 UPDATE 报文，应采用 "视为撤回 "的方法进行处理。
Furthermore, the normative reference to [OPT-TRANS-BGP] in [RFC6368] is removed.
此外，删除了 [RFC6368] 中对 [OPT-TRANS-BGP] 的规范性引用。
A document that specifies a new BGP attribute MUST provide specifics regarding what constitutes an error for that attribute and how that error is to be handled. Allowable error-handling approaches are detailed in Section 2. The "treat-as-withdraw" approach is generally preferred and the "session reset" approach is discouraged. Authors of BGP documents are also reminded to review the discussion of optional transitive attributes in the first paragraph of the Introduction of this document. The document SHOULD also provide consideration of what debugging facilities may be required to permit issues caused by a malformed attribute to be diagnosed.
指定新 BGP 属性的文件必须提供有关该属性错误的具体内容以及错误的处理方法。第 2 节详细介绍了允许的错误处理方法。一般来说，"视作撤回"（treat-as-withdraw）方法更受欢迎，而 "会话重置"（session reset）方法则不受欢迎。还提醒 BGP 文档的作者回顾本文档导言第一段中关于可选传递属性的讨论。文件还应考虑可能需要哪些调试设施来诊断由畸形属性引起的问题。
For any malformed attribute that is handled by the "attribute discard" instead of the "treat-as-withdraw" approach, it is critical to consider the potential impact of doing so. In particular, if the attribute in question has or may have an effect on route selection or installation, the presumption is that discarding it is unsafe unless careful analysis proves otherwise. The analysis should take into account the tradeoff between preserving connectivity and potential side effects.
对于采用 "属性丢弃 "而非 "视作撤回 "方法处理的任何畸形属性，考虑这样做的潜在影响至关重要。特别是，如果有关属性对路由选择或安装有影响或可能有影响，那么除非仔细分析证明不安全，否则就推定丢弃该属性是不安全的。分析时应考虑保持连通性与潜在副作用之间的权衡。
Authors can refer to Section 7 for examples.
作者可参考第 7 节中的示例。
This specification addresses the vulnerability of a BGP speaker to a potential attack whereby a distant attacker can generate a malformed optional transitive attribute that is not recognized by intervening routers. Since the intervening routers do not recognize the attribute, they propagate it without checking it. When the malformed attribute arrives at a router that does recognize the given attribute type, that router resets the session over which it arrived. Since significant fan-out can occur between the attacker and the routers that do recognize the attribute type, this attack could potentially be particularly harmful.
本规范解决了 BGP 发言者易受潜在攻击影响的问题，即远方的攻击者可以生成一个畸形的可选传递属性，而中间的路由器无法识别该属性。由于中间路由器无法识别该属性，因此它们会在不检查该属性的情况下传播该属性。当畸形属性到达一个能识别给定属性类型的路由器时，该路由器会重置其到达的会话。由于在攻击者和识别属性类型的路由器之间会出现大量扇出，因此这种攻击的潜在危害特别大。
The improved error handling of this specification could in theory interact badly with some now-known weaker cryptographic mechanisms should such be used in future to secure BGP. For example, if a (fictional) mechanism that did not supply data integrity was used, an attacker could manipulate ciphertext in any attempt to change or observe how the receiver reacts. Absent this specification, the BGP session would have been terminated; with this specification, the attacker could make potentially many attempts. While such a confidentiality-only mechanism would not be defined today, we have in the past seen mechanism definitions that result in similar, though not as obviously exploitable, vulnerabilities [RFC7366]. The approach recommended today to avoid such issues is to prefer use of Authenticated Encryption with Additional Data (AEAD) ciphers [RFC5116] and thus to discard messages that don't verify.
从理论上讲，本规范改进的错误处理方法可能会与某些已知的较弱加密机制产生不良影响，如果这些机制将来被用于保护 BGP 的安全的话。例如，如果使用一种（虚构的）不提供数据完整性的机制，攻击者就可以篡改密文，试图改变或观察接收者的反应。如果没有这种规范，BGP 会话就会被终止；而有了这种规范，攻击者就有可能多次尝试。虽然今天不会定义这种只保密的机制，但我们过去看到过导致类似漏洞的机制定义，尽管没有那么明显的可利用性[RFC7366]。为避免此类问题，目前推荐的方法是优先使用附加数据验证加密（AEAD）密码[RFC5116]，从而丢弃无法验证的信息。
In other respects, this specification does not change BGP's security characteristics.
在其他方面，本规范不会改变 BGP 的安全特性。
[IANA-BGP-ATTRS] IANA, "BGP Path Attributes", <http://www.iana.org/assignments/bgp-parameters>.
[IANA-BGP-ATTRS] IANA，"BGP 路径属性"，<http://www.iana.org/assignments/bgp-parameters>。
[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., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, <http://www.rfc-editor.org/info/rfc1997>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, <http://www.rfc-editor.org/info/rfc4271>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, <http://www.rfc-editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, February 2006, <http://www.rfc-editor.org/info/rfc4360>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, February 2006, <http://www.rfc-editor.org/info/rfc4360>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006, <http://www.rfc-editor.org/info/rfc4456>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route Reflection：An Alternative to Full Mesh Internal BGP (IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006, <http://www.rfc-editor.org/info/rfc4456>.
[RFC4724] Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y. Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724, DOI 10.17487/RFC4724, January 2007, <http://www.rfc-editor.org/info/rfc4724>.
[RFC4724] Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y. Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724, DOI 10.17487/RFC4724, January 2007, <http://www.rfc-editor.org/info/rfc4724>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, DOI 10.17487/RFC4760, January 2007, <http://www.rfc-editor.org/info/rfc4760>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 4760, DOI 10.17487/RFC4760, January 2007, <http://www.rfc-editor.org/info/rfc4760>.
[RFC5543] Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP Traffic Engineering Attribute", RFC 5543, DOI 10.17487/RFC5543, May 2009, <http://www.rfc-editor.org/info/rfc5543>.
[RFC5543] Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP Traffic Engineering Attribute", RFC 5543, DOI 10.17487/RFC5543, May 2009, <http://www.rfc-editor.org/info/rfc5543>。
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009, <http://www.rfc-editor.org/info/rfc5701>.
[RFC5701] Rekhter, Y., "IPv6 地址特定 BGP 扩展社区属性"，RFC 5701，DOI 10.17487/RFC5701，2009 年 11 月，<http://www.rfc-editor.org/info/rfc5701>。
[RFC6368] Marques, P., Raszuk, R., Patel, K., Kumaki, K., and T. Yamagata, "Internal BGP as the Provider/Customer Edge Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 6368, DOI 10.17487/RFC6368, September 2011, <http://www.rfc-editor.org/info/rfc6368>.
[RFC6368] Marques, P., Raszuk, R., Patel, K., Kumaki, K., and T. Yamagata, "Internal BGP as the Provider/Customer Edge Protocol for BGP/MPLS IP Virtual Private Networks (VPNs)", RFC 6368, DOI 10.17487/RFC6368, September 2011, <http://www.rfc-editor.org/info/rfc6368>。
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet Autonomous System (AS) Number Space", RFC 6793, DOI 10.17487/RFC6793, December 2012, <http://www.rfc-editor.org/info/rfc6793>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet Autonomous System (AS) Number Space", RFC 6793, DOI 10.17487/RFC6793, December 2012, <http://www.rfc-editor.org/info/rfc6793>.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008, <http://www.rfc-editor.org/info/rfc5116>.
[RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008, <http://www.rfc-editor.org/info/rfc5116>.
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network Layer Reachability Information with an IPv6 Next Hop", RFC 5549, DOI 10.17487/RFC5549, May 2009, <http://www.rfc-editor.org/info/rfc5549>.
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network Layer Reachability Information with an IPv6 Next Hop", RFC 5549, DOI 10.17487/RFC5549, May 2009, <http://www.rfc-editor.org/info/rfc5549>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, <http://www.rfc-editor.org/info/rfc6514>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP Encodings and Procedures for Multicast in MPLS/BGP IP VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, <http://www.rfc-editor.org/info/rfc6514>。
[RFC7117] Aggarwal, R., Ed., Kamite, Y., Fang, L., Rekhter, Y., and C. Kodeboniya, "Multicast in Virtual Private LAN Service (VPLS)", RFC 7117, DOI 10.17487/RFC7117, February 2014, <http://www.rfc-editor.org/info/rfc7117>.
[RFC7117] Aggarwal, R., Ed., Kamite, Y., Fang, L., Rekhter, Y., and C. Kodeboniya, "Multicast in Virtual Private LAN Service (VPLS)", RFC 7117, DOI 10.17487/RFC7117, February 2014, <http://www.rfc-editor.org/info/rfc7117>。
[RFC7366] Gutmann, P., "Encrypt-then-MAC for Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", RFC 7366, DOI 10.17487/RFC7366, September 2014, <http://www.rfc-editor.org/info/rfc7366>.
[RFC7366] Gutmann, P., "Encrypt-then-MAC for Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", RFC 7366, DOI 10.17487/RFC7366, September 2014, <http://www.rfc-editor.org/info/rfc7366>。
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, <http://www.rfc-editor.org/info/rfc7432>.
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, <http://www.rfc-editor.org/info/rfc7432>。
Acknowledgements
致谢
The authors wish to thank Juan Alcaide, Deniz Bahadir, Ron Bonica, Mach Chen, Andy Davidson, Bruno Decraene, Stephen Farrell, Rex Fernando, Jeff Haas, Chris Hall, Joel Halpern, Dong Jie, Akira Kato, Miya Kohno, Warren Kumari, Tony Li, Alton Lo, Shin Miyakawa, Tamas Mondal, Jonathan Oddy, Tony Przygienda, Robert Raszuk, Yakov Rekhter, Eric Rosen, Shyam Sethuram, Rob Shakir, Naiming Shen, Adam Simpson, Ananth Suryanarayana, Kaliraj Vairavakkalai, Lili Wang, and Ondrej Zajicek for their observations and discussion of this topic and review of this document.
作者感谢 Juan Alcaide、Deniz Bahadir、Ron Bonica、Mach Chen、Andy Davidson、Bruno Decraene、Stephen Farrell、Rex Fernando、Jeff Haas、Chris Hall、Joel Halpern、Dong Jie、Akira Kato、Miya Kohno、Warren Kumari、Tony Li、Alton Lo、Shin Miyakawa、Tamas Mondal、Jonathan Oddy、Tony Przygienda、Robert Raszuk、Yakov Rekhter、Eric Rosen、Shyam Sethuram、Rob Shakir、Naiming Shen、Adam Simpson、Ananth Suryanarayana、Kaliraj Vairavakkalai、Lili Wang 和 Ondrej Zajicek，感谢他们对本主题的观察和讨论以及对本文档的审阅。
Authors' Addresses
作者地址
Enke Chen (editor) Cisco Systems, Inc.
Enke Chen（编辑） 思科系统公司
Email: [email protected]
John G. Scudder (editor) Juniper Networks
约翰-斯卡德（John G. Scudder）（编辑） 瞻博网络
Email: [email protected]
Pradosh Mohapatra Sproute Networks
Pradosh Mohapatra Sproute 网络公司
Email: [email protected]
Keyur Patel Cisco Systems, Inc.
Keyur Patel 思科系统公司
Email: [email protected]