Internet Engineering Task Force (IETF) L. Ginsberg, Ed.
Request for Comments: 7794 Cisco Systems
Category: Standards Track B. Decraene
ISSN: 2070-1721 Orange
S. Previdi
Cisco Systems
X. Xu
Huawei
U. Chunduri
Ericsson
March 2016
Internet Engineering Task Force (IETF) L. Ginsberg, Ed.
Request for Comments: 7794 Cisco Systems
Category: Standards Track B. Decraene
ISSN: 2070-1721 Orange
S. Previdi
Cisco Systems
X. Xu
Huawei
U. Chunduri
Ericsson
March 2016
IS-IS Prefix Attributes for Extended IPv4 and IPv6 Reachability
扩展IPv4和IPv6可达性的IS-IS前缀属性
Abstract
摘要
This document introduces new sub-TLVs to support advertisement of IPv4 and IPv6 prefix attribute flags and the source router ID of the router that originated a prefix advertisement.
本文档介绍了新的子TLV，以支持IPv4和IPv6前缀属性标志的播发以及发起前缀播发的路由器的源路由器ID。
Status of This Memo
关于下段备忘
This is an Internet Standards Track document.
这是一份互联网标准跟踪文件。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关互联网标准的更多信息，请参见RFC 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/rfc7794.
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/rfc7794.
Copyright Notice
版权公告
Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2016 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
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. New Sub-TLVs for Extended Reachability TLVs . . . . . . . . . 3
2.1. IPv4/IPv6 Extended Reachability Attribute Flags . . . . . 4
2.2. IPv4/IPv6 Source Router ID . . . . . . . . . . . . . . . 5
2.3. Advertising Router IDs . . . . . . . . . . . . . . . . . 6
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 8
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. New Sub-TLVs for Extended Reachability TLVs . . . . . . . . . 3
2.1. IPv4/IPv6 Extended Reachability Attribute Flags . . . . . 4
2.2. IPv4/IPv6 Source Router ID . . . . . . . . . . . . . . . 5
2.3. Advertising Router IDs . . . . . . . . . . . . . . . . . 6
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 8
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
IS-IS is a link-state routing protocol defined in [ISO10589] and [RFC1195]. Extensions in support of advertising new forms of IPv4/IPv6 prefix reachability are defined in [RFC5305], [RFC5308], and [RFC5120].
IS-IS是[ISO10589]和[RFC1195]中定义的链路状态路由协议。[RFC5305]、[RFC5308]和[RFC5120]中定义了支持新形式IPv4/IPv6前缀可达性广告的扩展。
There are existing use cases in which knowing additional attributes of a prefix is useful.
在现有的用例中，了解前缀的附加属性是很有用的。
It is useful to know whether or not an advertised prefix is directly connected to the advertising router. In the case of Segment Routing as described in [SR], knowing whether or not a prefix is directly connected determines what action should be taken as regards processing of labels associated with an incoming packet.
了解播发前缀是否直接连接到播发路由器是很有用的。在[SR]中所述的段路由的情况下，知道前缀是否直接连接决定了在处理与传入数据包相关联的标签时应采取的措施。
It is useful to know what addresses can be used as addresses of the node in support of services (e.g., Remote Loop Free Alternate (RLFA) endpoint).
了解哪些地址可以用作支持服务的节点的地址（例如，远程无环备用（RLFA）端点）非常有用。
Current formats of the Extended Reachability TLVs for both IPv4 and IPv6 are fixed and do not allow the introduction of additional flags without backwards compatibility issues. Therefore, this document defines a new sub-TLV that supports the advertisement of attribute flags associated with prefix advertisements.
IPv4和IPv6的扩展可访问性TLV的当前格式是固定的，不允许在没有向后兼容性问题的情况下引入附加标志。因此，本文档定义了一个新的子TLV，它支持与前缀播发关联的属性标志的播发。
In cases where multiple node addresses are advertised by a given router, it is also useful to be able to associate all of these addresses with a single Router ID even when prefixes are advertised outside of the area in which they originated. Therefore, a new sub-TLV is introduced to advertise the Router ID of the originator of a prefix advertisement.
在给定路由器播发多个节点地址的情况下，即使在前缀在其来源区域之外播发时，也可以将所有这些地址与单个路由器ID关联起来。因此，引入了一个新的子TLV来通告前缀通告的发起方的路由器ID。
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
本文件中的关键词“必须”、“不得”、“要求”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119[RFC2119]中所述进行解释。
The following new sub-TLVs are introduced:
引入了以下新的子TLV：
o Prefix Attribute Flags
o 前缀属性标志
o IPv4 Source Router ID
o IPv4源路由器ID
o IPv6 Source Router ID
o IPv6源路由器ID
All sub-TLVs are applicable to TLVs 135, 235, 236, and 237.
所有子TLV均适用于TLV 135、235、236和237。
This sub-TLV supports the advertisement of additional flags associated with a given prefix advertisement. The behavior of each flag when a prefix advertisement is leaked from one level to another (upwards or downwards) is explicitly defined below.
此子TLV支持与给定前缀播发关联的附加标志的播发。下面明确定义了前缀播发从一个级别泄漏到另一个级别（向上或向下）时每个标志的行为。
All flags are applicable to TLVs 135, 235, 236, and 237, unless otherwise stated.
除非另有说明，否则所有标志均适用于TLV 135、235、236和237。
Prefix Attribute Flags Type: 4 Length: Number of octets of the Value field. Value:
前缀属性标志类型：4长度：值字段的八位字节数。价值：
(Length * 8) bits.
（长度*8）位。
0 1 2 3 4 5 6 7...
+-+-+-+-+-+-+-+-+...
|X|R|N| ...
+-+-+-+-+-+-+-+-+...
0 1 2 3 4 5 6 7...
+-+-+-+-+-+-+-+-+...
|X|R|N| ...
+-+-+-+-+-+-+-+-+...
Bits are defined/sent starting with Bit 0 defined below. Additional bit definitions that may be defined in the future SHOULD be assigned in ascending bit order so as to minimize the number of bits that will need to be transmitted.
从下面定义的位0开始定义/发送位。将来可能定义的附加位定义应以升序位顺序分配，以最小化需要传输的位的数量。
Undefined bits MUST be transmitted as 0 and MUST be ignored on receipt.
未定义的位必须作为0传输，并且在接收时必须忽略。
Bits that are NOT transmitted MUST be treated as if they are set to 0 on receipt.
未传输的位必须视为在接收时设置为0。
X-Flag: External Prefix Flag (Bit 0) Set if the prefix has been redistributed from another protocol. This includes the case where multiple virtual routers are supported and the source of the redistributed prefix is another IS-IS instance.
X-Flag：如果前缀已从其他协议重新分配，则设置外部前缀标志（位0）。这包括支持多个虚拟路由器且重新分配的前缀的来源是另一个is-is实例的情况。
The flag MUST be preserved when leaked between levels.
在级别之间泄漏时，必须保留该标志。
In TLVs 236 and 237, this flag SHOULD always be sent as 0 and MUST be ignored on receipt. This is because there is an existing X flag defined in the fixed format of these TLVs as specified in [RFC5308] and [RFC5120].
在TLV 236和237中，此标志应始终作为0发送，并且在收到时必须忽略。这是因为[RFC5308]和[RFC5120]中规定的这些TLV的固定格式中定义了一个现有的X标志。
R-Flag: Re-advertisement Flag (Bit 1) Set when the prefix has been leaked from one level to another (upwards or downwards).
R标志：当前缀从一个级别泄漏到另一个级别（向上或向下）时设置的重新公布标志（位1）。
N-flag: Node Flag (Bit 2) Set when the prefix identifies the advertising router, i.e., the prefix is a host prefix advertising a globally reachable address typically associated with a loopback address.
N-flag：当前缀标识播发路由器时设置的节点标志（位2），即前缀是播发通常与环回地址关联的全局可访问地址的主机前缀。
The advertising router MAY choose to NOT set this flag even when the above conditions are met.
即使满足上述条件，广告路由器也可以选择不设置此标志。
If the flag is set and the prefix length is NOT a host prefix (/32 for IPV4, /128 for IPv6), then the flag MUST be ignored. The flag MUST be preserved when leaked between levels.
如果设置了该标志且前缀长度不是主机前缀（IPV4为/32，IPv6为/128），则必须忽略该标志。在级别之间泄漏时，必须保留该标志。
When a reachability advertisement is leaked from one level to another, the source of the original advertisement is unknown. In cases where the advertisement is an identifier for the advertising router (e.g., with the N-flag set in the Prefix Attribute Flags sub-TLV as described in Section 2.1), it may be useful for other routers to know the source of the advertisement. The sub-TLVs defined below provide that information.
当可达性广告从一个级别泄漏到另一个级别时，原始广告的来源是未知的。在广告是广告路由器的标识符的情况下（例如，如第2.1节所述，在前缀属性标志子TLV中设置了N标志），其他路由器了解广告的来源可能是有用的。下面定义的子TLV提供了该信息。
Note that the Router ID advertised is always the Router ID of the IS-IS instance that originated the advertisement. This would be true even if the prefix had been learned from another protocol (i.e., with the X-flag set as defined in Section 2.1).
请注意，播发的路由器ID始终是发起播发的is-is实例的路由器ID。即使前缀是从另一个协议（即，使用第2.1节中定义的X标志集）学习的，这也是正确的。
IPv4 Source Router ID Type: 11 Length: 4 Value: IPv4 Router ID of the source of the advertisement
IPv4源路由器ID类型：11长度：4值：播发源的IPv4路由器ID
Inclusion of this TLV is optional and MAY occur in TLVs 135, 235, 236, or 237. When included, the value MUST be identical to the value advertised in the Traffic Engineering router ID (TLV 134) defined in [RFC5305].
包含该TLV是可选的，可能出现在TLV 135、235、236或237中。包括时，该值必须与[RFC5305]中定义的流量工程路由器ID（TLV 134）中公布的值相同。
If present the sub-TLV MUST be included when the prefix advertisement is leaked to another level.
如果存在子TLV，则当前缀广告泄漏到另一个级别时，必须包括子TLV。
IPv6 Source Router ID Type: 12 Length: 16 Value: IPv6 Router ID of the source of the advertisement
IPv6源路由器ID类型：12长度：16值：播发源的IPv6路由器ID
Inclusion of this TLV is optional and MAY occur in TLVs 135, 235, 236, or 237. When included, the value MUST be identical to the value advertised in the IPv6 TE Router ID (TLV 140) defined in [RFC6119].
包含该TLV是可选的，可能出现在TLV 135、235、236或237中。包含时，该值必须与[RFC6119]中定义的IPv6 TE路由器ID（TLV 140）中公布的值相同。
If present, the sub-TLV MUST be included when the prefix advertisement is leaked to another level.
如果存在，当前缀广告泄漏到另一个级别时，必须包括子TLV。
[RFC5305] and [RFC6119] define the advertisement of router IDs for IPv4 and IPv6, respectively. Although both documents discuss the use of router ID in the context of Traffic Engineering (TE), the advertisement of router IDs is explicitly allowed for purposes other than TE. The use of router IDs to identify the source of a prefix advertisement as defined in Section 2.2 is one such use case. Therefore, whenever an IPv4 or IPv6 Source Router ID sub-TLV (as defined in Section 2.2) is used, the originating router SHOULD also advertise the corresponding address-family-specific router ID TLV.
[RFC5305]和[RFC6119]分别定义IPv4和IPv6路由器ID的公布。尽管这两份文件都讨论了在流量工程（TE）环境中使用路由器ID，但明确允许出于TE以外的目的发布路由器ID。使用路由器ID识别第2.2节中定义的前缀广告源就是这样一种用例。因此，每当使用IPv4或IPv6源路由器ID子TLV（如第2.2节所定义）时，发起路由器还应公布相应的地址系列特定的路由器ID TLV。
This document adds the following new sub-TLVs to the registry of sub-TLVs for TLVs 135, 235, 236, and 237.
本文件将以下新的子TLV添加到TLV 135、235、236和237的子TLV注册表中。
Value: 4 Name: Prefix Attribute Flags
值：4名称：前缀属性标志
Value: 11 Name: IPv4 Source Router ID
值：11名称：IPv4源路由器ID
Value: 12 Name: IPv6 Source Router ID
值：12名称：IPv6源路由器ID
This document also introduces a new registry for bit values in the Prefix Attribute Flags sub-TLV. The registration policy is Expert Review as defined in [RFC5226]. This registry is part of the "IS-IS TLV Codepoints" registry. The name of the registry is "Bit Values for Prefix Attribute Flags Sub-TLV". The defined values are:
本文档还介绍了前缀属性标志子TLV中位值的新注册表。注册政策为[RFC5226]中定义的专家评审。此注册表是“is-is TLV代码点”注册表的一部分。注册表的名称是“前缀属性标志子TLV的位值”。定义的值为：
Bit # Name
----- ------------------------------
0 External Prefix Flag (X-flag)
1 Re-advertisement Flag (R-flag)
2 Node Flag (N-flag)
Bit # Name
----- ------------------------------
0 External Prefix Flag (X-flag)
1 Re-advertisement Flag (R-flag)
2 Node Flag (N-flag)
Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310].
IS-IS的安全问题见[RFC5304]和[RFC5310]。
Advertisement of the additional information defined in this document introduces no new security concerns.
公布本文件中定义的附加信息不会带来新的安全问题。
[ISO10589] International Organization for Standardization, "Intermediate system to Intermediate system intra-domain routeing information exchange protocol for use in conjunction with the protocol for providing the connectionless-mode Network Service (ISO 8473)", ISO/IEC 10589:2002, Second Edition, Nov. 2002.
[ISO10589]国际标准化组织，“与提供无连接模式网络服务协议一起使用的中间系统到中间系统域内路由信息交换协议（ISO 8473）”，ISO/IEC 10589:2002，第二版，2002年11月。
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, DOI 10.17487/RFC1195, December 1990, <http://www.rfc-editor.org/info/rfc1195>.
[RFC1195]Callon，R.“OSI IS-IS在TCP/IP和双环境中的路由使用”，RFC 1195，DOI 10.17487/RFC1195，1990年12月<http://www.rfc-editor.org/info/rfc1195>.
[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.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<http://www.rfc-editor.org/info/rfc2119>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs)", RFC 5120, DOI 10.17487/RFC5120, February 2008, <http://www.rfc-editor.org/info/rfc5120>.
[RFC5120]Przygienda，T.，Shen，N.，和N.Sheth，“M-ISIS：中间系统到中间系统（IS-ISs）的多拓扑（MT）路由”，RFC 5120，DOI 10.17487/RFC5120，2008年2月<http://www.rfc-editor.org/info/rfc5120>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, DOI 10.17487/RFC5226, May 2008, <http://www.rfc-editor.org/info/rfc5226>.
[RFC5226]Narten，T.和H.Alvestrand，“在RFCs中编写IANA注意事项部分的指南”，BCP 26，RFC 5226，DOI 10.17487/RFC5226，2008年5月<http://www.rfc-editor.org/info/rfc5226>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic Authentication", RFC 5304, DOI 10.17487/RFC5304, October 2008, <http://www.rfc-editor.org/info/rfc5304>.
[RFC5304]Li，T.和R.Atkinson，“IS-IS加密认证”，RFC 5304，DOI 10.17487/RFC5304，2008年10月<http://www.rfc-editor.org/info/rfc5304>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, DOI 10.17487/RFC5305, October 2008, <http://www.rfc-editor.org/info/rfc5305>.
[RFC5305]Li，T.和H.Smit，“交通工程的IS-IS扩展”，RFC 5305，DOI 10.17487/RFC5305，2008年10月<http://www.rfc-editor.org/info/rfc5305>.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, DOI 10.17487/RFC5308, October 2008, <http://www.rfc-editor.org/info/rfc5308>.
[RFC5308]Hopps，C.，“使用IS-IS路由IPv6”，RFC 5308，DOI 10.17487/RFC5308，2008年10月<http://www.rfc-editor.org/info/rfc5308>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC 5310, DOI 10.17487/RFC5310, February 2009, <http://www.rfc-editor.org/info/rfc5310>.
[RFC5310]Bhatia，M.，Manral，V.，Li，T.，Atkinson，R.，White，R.，和M.Fanto，“IS-IS通用密码认证”，RFC 5310，DOI 10.17487/RFC5310，2009年2月<http://www.rfc-editor.org/info/rfc5310>.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, February 2011, <http://www.rfc-editor.org/info/rfc6119>.
[RFC6119]Harrison，J.，Berger，J.，和M.Bartlett，“IS-IS中的IPv6流量工程”，RFC 6119，DOI 10.17487/RFC6119，2011年2月<http://www.rfc-editor.org/info/rfc6119>.
[SR] Previdi, S., Ed., Filsfils, C., Bashandy, A., Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, "IS-IS Extensions for Segment Routing", Work in Progress, draft-ietf-isis-segment-routing-extensions-06, December 2015.
[SR]Previdi，S.，Ed.，Filsfils，C.，Bashandy，A.，Gredler，H.，Litkowski，S.，Decarene，B.，和J.Tantsura，“分段布线的IS-IS扩展”，正在进行中的工作，草案-ietf-isis-Segment-Routing-Extensions-062015年12月。
Contributors
贡献者
The following people gave a substantial contribution to the content of this document:
以下人士对本文件的内容做出了重大贡献：
Clarence Filsfils Cisco Systems
克拉伦斯菲尔斯思科系统公司
Email: cf@cisco.com
Email: cf@cisco.com
Stephane Litkowski Orange Business Service
Stephane Litkowski橙色商务服务
Email: stephane.litkowski@orange.com
Email: stephane.litkowski@orange.com
Authors' Addresses
作者地址
Les Ginsberg (editor) Cisco Systems 510 McCarthy Blvd. Milpitas, CA 95035 United States
莱斯·金斯伯格（编辑）思科系统公司麦卡锡大道510号。美国加利福尼亚州米尔皮塔斯95035
Email: ginsberg@cisco.com
Email: ginsberg@cisco.com
Bruno Decraene Orange 38 rue du General Leclerc Issy Moulineaux cedex 9 92794 France
法国莱克莱尔将军街38号布鲁诺·德雷恩·奥兰治伊西·穆尔内奥克斯9 92794
Email: bruno.decraene@orange.com
Email: bruno.decraene@orange.com
Stefano Previdi Cisco Systems Via Del Serafico 200 Rome 0144 Italy
Stefano Previdi Cisco Systems Via Del Serafico 200罗马0144意大利
Email: sprevidi@cisco.com
Email: sprevidi@cisco.com
Xiaohu Xu Huawei
徐小虎
Email: xuxiaohu@huawei.com
Email: xuxiaohu@huawei.com
Uma Chunduri Ericsson
乌玛·春杜里·爱立信
Email: uma.chunduri@ericsson.com
Email: uma.chunduri@ericsson.com