Internet Engineering Task Force (IETF) A. Banerjee
Request for Comments: 6165 Cisco Systems
Category: Standards Track D. Ward
ISSN: 2070-1721 Juniper Networks
April 2011
Internet Engineering Task Force (IETF) A. Banerjee
Request for Comments: 6165 Cisco Systems
Category: Standards Track D. Ward
ISSN: 2070-1721 Juniper Networks
April 2011
Extensions to IS-IS for Layer-2 Systems
第2层系统IS-IS的扩展
Abstract
摘要
This document specifies the Intermediate System to Intermediate System (IS-IS) extensions necessary to support link state routing for any protocols running directly over Layer-2. While supporting this concept involves several pieces, this document only describes extensions to IS-IS. Furthermore, the Type, Length, Value pairs (TLVs) described in this document are generic Layer-2 additions, and specific ones as needed are defined in the IS-IS technology-specific extensions. We leave it to the systems using these IS-IS extensions to explain how the information carried in IS-IS is used.
本文档指定了中间系统到中间系统（IS-IS）扩展，该扩展是支持直接在第2层上运行的任何协议的链路状态路由所必需的。虽然支持此概念涉及多个部分，但本文档仅描述IS-IS的扩展。此外，本文档中描述的类型、长度、值对（TLV）是通用的第2层添加，具体的TLV在IS-IS技术特定扩展中定义。我们让使用这些IS-IS扩展的系统来解释如何使用IS-IS中携带的信息。
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/rfc6165.
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/rfc6165.
Copyright Notice
版权公告
Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2011 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. Overview ........................................................2
1.1. Terminology ................................................3
2. TLV Enhancements to IS-IS .......................................3
2.1. Multi-Topology-Aware Port Capability TLV ...................3
2.2. The MAC-Reachability TLV ...................................4
3. Acknowledgements ................................................5
4. Security Considerations .........................................5
5. IANA Considerations .............................................5
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................6
1. Overview ........................................................2
1.1. Terminology ................................................3
2. TLV Enhancements to IS-IS .......................................3
2.1. Multi-Topology-Aware Port Capability TLV ...................3
2.2. The MAC-Reachability TLV ...................................4
3. Acknowledgements ................................................5
4. Security Considerations .........................................5
5. IANA Considerations .............................................5
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................6
There are a number of systems (for example, [RBRIDGES], [802.1aq], and [OTV]) that use Layer-2 addresses carried in a link state routing protocol, specifically Intermediate System to Intermediate System [IS-IS] [RFC1195], to provide true Layer-2 routing. In almost all the technologies mentioned above, classical Layer-2 packets are encapsulated with an outer header. The outer header format varies across all these technologies. This outer header is used to route the encapsulated packets to their destination.
有许多系统（例如，[RBRIDGES]、[802.1aq]和[OTV]）使用链路状态路由协议中携带的第二层地址，特别是中间系统到中间系统[IS-IS][RFC1195]，以提供真正的第二层路由。在上面提到的几乎所有技术中，经典的第2层数据包都是用外部报头封装的。所有这些技术的外部标题格式都不同。此外部报头用于将封装的数据包路由到其目的地。
Each Intermediate System (IS) advertises one or more IS-IS Link State Protocol Data Units (PDUs) with routing information. Each Link State PDU (LSP) is composed of a fixed header and a number of tuples, each consisting of a Type, a Length, and a Value. Such tuples are
每个中间系统（IS）用路由信息播发一个或多个IS-IS链路状态协议数据单元（PDU）。每个链路状态PDU（LSP）由一个固定的头和多个元组组成，每个元组由一个类型、一个长度和一个值组成。这样的元组是
commonly known as TLVs. In this document, we specify a set of TLVs to be added to [IS-IS] PDUs, to support these proposed systems. The TLVs are generic Layer-2 additions, and specific ones, as needed, are defined in the IS-IS technology-specific extensions. This document does not propose any new forwarding mechanisms using this additional information carried within IS-IS.
通常称为TLV。在本文件中，我们指定一组TLV添加到[IS-IS]PDU，以支持这些建议的系统。TLV是通用的第2层添加，具体的TLV（根据需要）在IS-IS技术特定扩展中定义。本文件不建议使用IS-IS中的附加信息建立任何新的转发机制。
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。
This section specifies the enhancements for the TLVs that are needed in common by Layer-2 technologies.
本节规定了第2层技术共同需要的TLV增强功能。
The Multi-Topology-aware Port Capability (MT-PORT-CAP) is IS-IS TLV type 143 and has the following format:
多拓扑感知端口能力（MT-Port-CAP）为143型TLV，格式如下：
+-+-+-+-+-+-+-+-+
| Type=MTPORTCAP| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|R|R| Topology Identifier | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs (variable bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
| Type=MTPORTCAP| (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|R|R| Topology Identifier | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-TLVs (variable bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to MT-PORT-CAP TLV 143.
o 类型：TLV类型，设置为MT-PORT-CAP TLV 143。
o Length: Total number of bytes contained in the value field, including the length of the sub-TLVs carried in this TLV.
o 长度：值字段中包含的字节总数，包括此TLV中携带的子TLV的长度。
o R: Reserved 4 bits, MUST be sent as zero and ignored on receipt.
o R：保留的4位，必须作为零发送，并在接收时忽略。
o Topology Identifier: MT ID is a 12-bit field containing the MT ID of the topology being announced. This field when set to zero implies that it is being used to carry base topology information.
o 拓扑标识符：MT ID是一个12位字段，包含要宣布的拓扑的MT ID。当该字段设置为零时，表示该字段用于承载基本拓扑信息。
o Sub-TLVs: The MT-PORT-CAP TLV value contains sub-TLVs formatted as described in [RFC5305]. They are defined in the technology-specific documents.
o 子TLV：MT-PORT-CAP TLV值包含按照[RFC5305]中所述格式设置的子TLV。它们在技术特定文档中定义。
The MT-PORT-CAP TLV may occur multiple times and is carried within an IS-IS Hello (IIH) PDU.
MT-PORT-CAP TLV可能会出现多次，并在is-is Hello（IIH）PDU中携带。
The MAC-Reachability (MAC-RI) TLV is IS-IS TLV type 147 and has the following format:
MAC可达性（MAC-RI）TLV为-is TLV类型147，具有以下格式：
+-+-+-+-+-+-+-+-+
| Type= MAC-RI | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-id/Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (1) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (N) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
| Type= MAC-RI | (1 byte)
+-+-+-+-+-+-+-+-+
| Length | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Topology-id/Nickname | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Confidence | (1 byte)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESV | VLAN-ID | (2 bytes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (1) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ................. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC (N) (6 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Type: TLV Type, set to 147 (MAC-RI).
o 类型：TLV类型，设置为147（MAC-RI）。
o Length: Total number of bytes contained in the value field given by 5 + 6*n bytes.
o 长度：值字段中包含的字节总数，由5+6*n字节给出。
o Topology-id/Nickname : Depending on the technology in which it is used, this carries the topology-id or nickname. When this field is set to zero, this implies that the Media Access Control (MAC) addresses are reachable across all topologies or across all nicknames of the originating IS.
o 拓扑id/昵称：根据使用它的技术，它携带拓扑id或昵称。当此字段设置为零时，这意味着媒体访问控制（MAC）地址可跨发起is的所有拓扑或所有昵称访问。
o Confidence: This carries an 8-bit quantity indicating the confidence level in the MAC addresses being transported. Whether this field is used, and its semantics if used, are further defined by the specific protocol using Layer-2 IS-IS. If not used, it MUST be set to zero on transmission and be ignored on receipt.
o 置信度：它携带一个8位的数量，指示正在传输的MAC地址的置信度。是否使用此字段以及其语义（如果使用）由使用第2层is-is的特定协议进一步定义。如果未使用，则必须在传输时将其设置为零，并在接收时忽略。
o RESV: (4 bits) MUST be sent as zero and ignored on receipt.
o RESV：（4位）必须作为零发送，并在收到时忽略。
o VLAN-ID: This carries a 12-bit VLAN identifier that is valid for all subsequent MAC addresses in this TLV, or the value zero if no VLAN is specified.
o VLAN-ID：它携带一个12位VLAN标识符，该标识符对该TLV中的所有后续MAC地址有效，如果未指定VLAN，则值为零。
o MAC(i): This is the 48-bit MAC address reachable from the IS that is announcing this TLV.
o MAC（i）：这是48位MAC地址，可从发布此TLV的is访问。
The MAC-RI TLV is carried in a standard Link State PDU (LSP). This TLV can be carried multiple times in an LSP and in multiple LSPs. It MUST contain only unicast addresses. The manner in which these TLVs are generated by the various Layer-2 routing technologies and the manner in which they are consumed are detailed in the technology-specific documents.
MAC-RI TLV以标准链路状态PDU（LSP）承载。该TLV可在一个LSP和多个LSP中多次携带。它必须只包含单播地址。各种第2层路由技术生成这些TLV的方式以及使用它们的方式在技术特定文档中有详细说明。
In most of the technologies, these MAC-RI TLVs will translate to populating the hardware with these entries and with appropriate next-hop information as derived from the advertising IS.
在大多数技术中，这些MAC-RI TLV将转化为使用这些条目和从广告中获得的适当下一跳信息填充硬件。
The authors would like to thank Peter Ashwood-Smith, Donald E. Eastlake 3rd, Dino Farinacci, Don Fedyk, Les Ginsberg, Radia Perlman, Mike Shand, and Russ White for their useful comments.
作者要感谢彼得·阿什伍德·史密斯、唐纳德·E·伊斯特莱克三世、迪诺·法里纳奇、唐·费迪克、莱斯·金斯伯格、拉迪亚·帕尔曼、迈克·山德和罗斯·怀特的有用评论。
This document adds no additional security risks to IS-IS, nor does it provide any additional security for IS-IS.
本文件不会给IS-IS增加额外的安全风险，也不会为IS-IS提供任何额外的安全性。
This document specifies the definition of a set of new IS-IS TLVs -- the Port-Capability TLV (type 143) and the MAC-Reachability TLV (type 147). They are listed in the IS-IS TLV codepoint registry.
本文件规定了一组新IS-IS TLV的定义——端口能力TLV（143型）和MAC可达性TLV（147型）。它们列在IS-IS TLV代码点注册表中。
IIH LSP SNP MT-Port-Cap-TLV (143) X - - MAC-RI TLV (147) - X -
IIH LSP SNP MT端口帽TLV（143）X--MAC-RI TLV（147）-X-
[IS-IS] ISO/IEC 10589:2002, Second Edition, "Intermediate System to Intermediate System Intra-Domain Routing Information Exchange Protocol for use in Conjunction with the Protocol for Providing the Connectionless-mode Network Service (ISO 8473)", 2002.
[IS-IS]ISO/IEC 10589:2002，第二版，“与提供无连接模式网络服务的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）”，2002年。
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, December 1990.
[RFC1195]Callon，R.，“OSI IS-IS在TCP/IP和双环境中的路由使用”，RFC 11951990年12月。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008.
[RFC5305]Li，T.和H.Smit，“交通工程的IS-IS扩展”，RFC 5305，2008年10月。
[802.1aq] "Standard for Local and Metropolitan Area Networks / Virtual Bridged Local Area Networks / Amendment 8: Shortest Path Bridging, Draft IEEE P802.1aq/D1.5", 2008.
[802.1aq]“局域网和城域网/虚拟桥接局域网标准/修订件8：最短路径桥接，IEEE P802.1aq/D1.5草案”，2008年。
[OTV] Grover, H., Rao, D., and D. Farinacci, "Overlay Transport Virtualization", Work in Progress, October 2010.
[OTV]Grover，H.，Rao，D.，和D.Farinaci，“覆盖传输虚拟化”，正在进行的工作，2010年10月。
[RBRIDGES] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A. Ghanwani, "RBridges: Base Protocol Specification", Work in Progress, March 2010.
[RBRIDGES]R.帕尔曼、D.东湖三号、D.杜特、S.盖伊和A.加瓦尼，“RBRIDGES：基本协议规范”，正在进行的工作，2010年3月。
Authors' Addresses
作者地址
Ayan Banerjee Cisco Systems 170 W. Tasman Drive San Jose, CA 95138 USA
美国加利福尼亚州圣何塞塔斯曼大道170 W.Ayan Banerjee Cisco Systems，邮编95138
EMail: ayabaner@cisco.com
EMail: ayabaner@cisco.com
David Ward Juniper Networks 1194 N. Mathilda Ave. Sunnyvale, CA 94089-1206 USA
David Ward Juniper Networks美国加利福尼亚州桑尼维尔马蒂尔达大道北1194号，邮编94089-1206
Phone: +1-408-745-2000
EMail: dward@juniper.net
Phone: +1-408-745-2000
EMail: dward@juniper.net