Internet Engineering Task Force (IETF) J. Harrison
Request for Comments: 6119 J. Berger
Category: Standards Track M. Bartlett
ISSN: 2070-1721 Metaswitch Networks
February 2011
Internet Engineering Task Force (IETF) J. Harrison
Request for Comments: 6119 J. Berger
Category: Standards Track M. Bartlett
ISSN: 2070-1721 Metaswitch Networks
February 2011
IPv6 Traffic Engineering in IS-IS
IS-IS中的IPv6流量工程
Abstract
摘要
This document specifies a method for exchanging IPv6 traffic engineering information using the IS-IS routing protocol. This information enables routers in an IS-IS network to calculate traffic-engineered routes using IPv6 addresses.
本文档指定了使用IS-IS路由协议交换IPv6流量工程信息的方法。此信息使IS-IS网络中的路由器能够使用IPv6地址计算流量工程路由。
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/rfc6119.
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/rfc6119.
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。
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.
本文件可能包含2008年11月10日之前发布或公开的IETF文件或IETF贡献中的材料。控制某些材料版权的人员可能未授予IETF信托允许在IETF标准流程之外修改此类材料的权利。在未从控制此类材料版权的人员处获得充分许可的情况下，不得在IETF标准流程之外修改本文件，也不得在IETF标准流程之外创建其衍生作品，除了将其格式化以RFC形式发布或将其翻译成英语以外的其他语言。
The IS-IS routing protocol is defined in [IS-IS]. Each router generates a Link State PDU (LSP) that contains information describing the router and the links from the router. The information in the LSP is encoded in a variable length data structure consisting of a Type, Length, and Value. Such a data structure is referred to as a TLV.
IS-IS路由协议在[IS-IS]中定义。每个路由器生成一个链路状态PDU（LSP），其中包含描述路由器和来自路由器的链路的信息。LSP中的信息编码在由类型、长度和值组成的可变长度数据结构中。这种数据结构称为TLV。
[TE] and [GMPLS] define a number of TLVs and sub-TLVs that allow Traffic Engineering (TE) information to be disseminated by the IS-IS protocol [IS-IS]. The addressing information passed in these TLVs is IPv4 specific.
[TE]和[GMPLS]定义了许多TLV和子TLV，允许IS-IS协议[IS-IS]传播流量工程（TE）信息。在这些TLV中传递的寻址信息是特定于IPv4的。
[IPv6] describes how the IS-IS protocol can be used to carry out Shortest Path First (SPF) routing for IPv6. It does this by defining IPv6-specific TLVs that are analogous to the TLVs used by IS-IS for carrying IPv4 addressing information.
[IPv6]描述了如何使用IS-IS协议为IPv6执行最短路径优先（SPF）路由。它通过定义特定于IPv6的TLV来实现这一点，这些TLV类似于IS-IS用于承载IPv4寻址信息的TLV。
Multiprotocol Label Switching (MPLS) traffic engineering is very successful, and, as the use of IPv6 grows, there is a need to be able to support traffic engineering in IPv6 networks.
多协议标签交换（MPLS）流量工程非常成功，而且随着IPv6使用的增长，需要能够支持IPv6网络中的流量工程。
This document defines the TLVs that allow traffic engineering information (including Generalized-MPLS (GMPLS) TE information) to be carried in IPv6 IS-IS networks.
本文档定义了允许在IPv6 IS-IS网络中承载流量工程信息（包括通用MPLS（GMPLS）TE信息）的TLV。
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 [KEYWORDS].
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“应”、“不应”、“建议”、“可”和“可选”应按照[关键词]中所述进行解释。
Each IS-IS link has certain properties -- bandwidth, shared risk link groups (SRLGs), switching capabilities, and so on. The IS-IS extensions defined in [TE] and [GMPLS] describe how to associate these traffic engineering parameters with IS-IS links. These TLVs use IPv4 addresses to identify the link (or local/remote link identifiers on unnumbered links).
每个IS-IS链路都有特定的属性——带宽、共享风险链路组（SRLGs）、交换能力等等。[TE]和[GMPLS]中定义的IS-IS扩展描述了如何将这些流量工程参数与IS-IS链路相关联。这些TLV使用IPv4地址来标识链路（或未编号链路上的本地/远程链路标识符）。
When IPv6 is used, a numbered link may be identified by IPv4 and/or IPv6 interface addresses. The type of identifier used does not affect the properties of the link; it still has the same bandwidth, SRLGs, and switching capabilities.
使用IPv6时，可通过IPv4和/或IPv6接口地址来标识编号的链路。使用的标识符类型不影响链接的属性；它仍然具有相同的带宽、SRLGs和交换能力。
This document describes an approach for supporting IPv6 traffic engineering by defining TLV extensions that allow TE links and nodes to be identified by IPv6 addresses.
本文档描述了一种通过定义TLV扩展来支持IPv6流量工程的方法，TLV扩展允许通过IPv6地址标识TE链路和节点。
An IPv6 address can have global, unique-local, or link-local scope.
IPv6地址可以具有全局、唯一的本地或链接本地作用域。
- A global IPv6 address is valid within the scope of the Internet.
- 全局IPv6地址在Internet范围内有效。
- A unique-local IPv6 address is globally unique but is intended for local communication.
- 唯一的本地IPv6地址是全局唯一的，但用于本地通信。
- A link-local IPv6 address is valid only within the scope of a single link and may only be referenced on that link.
- 链路本地IPv6地址仅在单个链路范围内有效，并且只能在该链路上引用。
Because the IPv6 traffic engineering TLVs present in LSPs are propagated across networks, they MUST NOT use link-local addresses.
由于LSP中存在的IPv6流量工程TLV跨网络传播，因此它们不得使用链路本地地址。
IS-IS does not need to differentiate between global and unique-local addresses.
IS-IS不需要区分全局地址和唯一的本地地址。
This section lists the IP addresses used in the TLVs defined in [TE] and [GMPLS] and gives an overview of the required IPv6 equivalents.
本节列出了[TE]和[GMPLS]中定义的TLV中使用的IP地址，并概述了所需的IPv6等效物。
The TE Router ID TLV contains a stable IPv4 address that is routable, regardless of the state of each interface.
TE路由器ID TLV包含稳定的IPv4地址，无论每个接口的状态如何，该地址都是可路由的。
Similarly, for IPv6, it is useful to have a stable IPv6 address identifying a TE node. The IPv6 TE Router ID TLV is defined in Section 4.1.
类似地，对于IPv6，具有标识TE节点的稳定IPv6地址也很有用。IPv6 TE路由器ID TLV在第4.1节中定义。
This sub-TLV of the Extended IS Reachability TLV contains an IPv4 address for the local end of a link. The equivalent IPv6 Interface Address sub-TLV is defined in Section 4.2.
扩展IS可达性TLV的子TLV包含链路本地端的IPv4地址。第4.2节定义了等效IPv6接口地址子TLV。
This sub-TLV of the Extended IS Reachability TLV is used for point-to-point links and contains an IPv4 address for the neighbor's end of a link. The equivalent IPv6 Neighbor Address sub-TLV is defined in Section 4.3.
扩展IS可达性TLV的此子TLV用于点到点链路，并包含一个用于邻居链路末端的IPv4地址。第4.3节定义了等效IPv6邻居地址子TLV。
A router constructs the IPv4 Neighbor Address sub-TLV using one of the IPv4 addresses received in the IS-IS Hello (IIH) PDU from the neighbor on the link.
路由器使用IS-IS Hello（IIH）PDU中从链路上的邻居接收的IPv4地址之一构造IPv4邻居地址子TLV。
The IPv6 Neighbor Address sub-TLV contains a globally unique IPv6 address for the interface from the peer (which can be either a global or unique-local IPv6 address). The IPv6 Interface Address TLV defined in [IPv6] only contains link-local addresses when used in the IIH PDU. Hence, a neighbor's IP address from the IPv6 Interface Address TLV cannot be used when constructing the IPv6 Neighbor Address sub-TLV. Instead, we define an additional TLV, the IPv6 Global Interface Address TLV in Section 4.5. The IPv6 Global Interface Address TLV is included in IIH PDUs to provide the globally unique IPv6 address that a neighbor router needs in order to construct the IPv6 Neighbor Address sub-TLV.
IPv6邻居地址子TLV包含对等方接口的全局唯一IPv6地址（可以是全局或唯一的本地IPv6地址）。[IPv6]中定义的IPv6接口地址TLV在IIH PDU中使用时仅包含链路本地地址。因此，在构造IPv6邻居地址子TLV时，不能使用来自IPv6接口地址TLV的邻居IP地址。相反，我们在第4.5节中定义了一个附加的TLV，即IPv6全局接口地址TLV。IIH PDU中包含IPv6全局接口地址TLV，以提供邻居路由器构建IPv6邻居地址子TLV所需的全局唯一IPv6地址。
The SRLG TLV (type 138) defined in [GMPLS] contains the set of SRLGs associated with a link. The SRLG TLV identifies the link using either local/remote IPv4 addresses or, for point-to-point unnumbered links, link-local/remote identifiers. The SRLG TLV includes a flags field to indicate which type of identifier is used.
[GMPLS]中定义的SRLG TLV（138型）包含与链路相关的SRLG集。SRLG TLV使用本地/远程IPv4地址或链路本地/远程标识符（对于点对点未编号的链路）标识链路。SRLG TLV包括一个标志字段，用于指示所使用的标识符类型。
When only IPv6 is used, IPv4 addresses and link-local/remote identifiers are not available to identify the link, but IPv6 addresses can be used instead.
仅使用IPv6时，IPv4地址和链路本地/远程标识符不可用于标识链路，但可以使用IPv6地址。
There is no backward-compatible way to modify the SRLG TLV (type 138) to identify the link by IPv6 addresses; therefore, we need a new TLV.
没有向后兼容的方式修改SRLG TLV（类型138），以通过IPv6地址识别链路；因此，我们需要一种新的TLV。
The IPv6 SRLG TLV is defined in Section 4.4.
第4.4节定义了IPv6 SRLG TLV。
The IPv6 TE Router ID TLV is TLV type 140.
IPv6 TE路由器ID TLV是TLV类型140。
The IPv6 TE Router ID TLV contains a 16-octet IPv6 address. A stable global IPv6 address MUST be used, so that the router ID provides a routable address, regardless of the state of a node's interfaces.
IPv6 TE路由器ID TLV包含一个16字节的IPv6地址。必须使用稳定的全局IPv6地址，以便路由器ID提供可路由地址，而不管节点接口的状态如何。
If a router does not implement traffic engineering, it MAY include or omit the IPv6 TE Router ID TLV. If a router implements traffic engineering for IPv6, it MUST include this TLV in its LSP. This TLV MUST NOT be included more than once in an LSP.
如果路由器没有实现流量工程，它可能包括或省略IPv6 TE路由器ID TLV。如果路由器为IPv6实施流量工程，则必须在其LSP中包含此TLV。LSP中不得多次包含该TLV。
An implementation receiving an IPv6 TE Router ID TLV MUST NOT consider the router ID as a /128 reachable prefix in the standard SPF calculation because this can lead to forwarding loops when interacting with systems that do not support this TLV.
接收IPv6 TE路由器ID TLV的实现必须不考虑路由器ID作为标准SPF计算中的128可到达前缀，因为当与不支持该TLV的系统交互时，这可能导致转发循环。
The IPv6 Interface Address sub-TLV of the Extended IS Reachability TLV has sub-TLV type 12. It contains a 16-octet IPv6 address for the interface described by the containing Extended IS Reachability TLV. This sub-TLV can occur multiple times.
扩展IS可达性TLV的IPv6接口地址子TLV具有子TLV类型12。它包含由包含扩展IS可达性TLV描述的接口的16个八位IPv6地址。此子TLV可能发生多次。
Implementations MUST NOT inject a /128 prefix for the interface address into their routing or forwarding table because this can lead to forwarding loops when interacting with systems that do not support this sub-TLV.
实现不得将接口地址的/128前缀插入其路由或转发表中，因为这可能导致在与不支持此子TLV的系统交互时出现转发循环。
If a router implements the basic TLV extensions described in [TE], it MAY include or omit this sub-TLV. If a router implements IPv6 traffic engineering, it MUST include this sub-TLV (except on an unnumbered point-to-point link, in which case the Link-Local Interface Identifiers sub-TLV is used instead).
如果路由器实现了[TE]中描述的基本TLV扩展，则它可能包括或省略该子TLV。如果路由器实施IPv6流量工程，它必须包括此子TLV（在未编号的点到点链路上除外，在这种情况下，将使用链路本地接口标识符子TLV）。
This sub-TLV MUST NOT contain an IPv6 link-local address.
此子TLV不得包含IPv6链路本地地址。
The IPv6 Neighbor Address sub-TLV of the Extended IS Reachability TLV has sub-TLV type 13. It contains a 16-octet IPv6 address for a neighboring router on the link described by the (main) TLV. This sub-TLV can occur multiple times.
扩展IS可达性TLV的IPv6邻居地址子TLV具有子TLV类型13。它包含（主）TLV描述的链路上相邻路由器的16个八位IPv6地址。此子TLV可能发生多次。
Implementations MUST NOT inject a /128 prefix for the interface address into their routing or forwarding table because this can lead to forwarding loops when interacting with systems that do not support this sub-TLV.
实现不得将接口地址的/128前缀插入其路由或转发表中，因为这可能导致在与不支持此子TLV的系统交互时出现转发循环。
If a router implements the basic TLV extensions described in [TE], it MAY include or omit this sub-TLV. If a router implements IPv6 traffic engineering, it MUST include this sub-TLV for point-to-point links (except on an unnumbered point-to-point link, in which case the Link-Local Interface Identifiers sub-TLV is used instead).
如果路由器实现了[TE]中描述的基本TLV扩展，则它可能包括或省略该子TLV。如果路由器实施IPv6流量工程，它必须为点到点链路包含此子TLV（未编号的点到点链路除外，在这种情况下，将使用链路本地接口标识符子TLV）。
This sub-TLV MUST NOT contain an IPv6 link-local address.
此子TLV不得包含IPv6链路本地地址。
The IPv6 SRLG TLV has type 139. The TLV carries the Shared Risk Link Group information (see the "Shared Risk Link Group Information" section of [GMPLS-ROUTING]).
IPv6 SRLG TLV的类型为139。TLV携带共享风险链路组信息（参见[GMPLS-ROUTING]的“共享风险链路组信息”部分）。
It contains a data structure consisting of the following:
它包含由以下内容组成的数据结构：
- 6 octets of System ID - 1 octet of pseudonode number - 1 octet flags - 16 octets of IPv6 interface address - (optional) 16 octets of IPv6 neighbor address - (variable) list of SRLG values, where each element in the list has 4 octets
- 系统ID的6个八位字节-伪节点号的1个八位字节-1个八位字节标志-IPv6接口地址的16个八位字节-（可选）IPv6邻居地址的16个八位字节-（变量）SRLG值列表，其中列表中的每个元素有4个八位字节
The following illustrates the encoding of the Value field of the IPv6 SRLG TLV.
以下说明了IPv6 SRLG TLV的值字段的编码。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID (cont.) | Pseudonode num| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (optional) IPv6 neighbor address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ............ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID (cont.) | Pseudonode num| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 interface address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (optional) IPv6 neighbor address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 neighbor address (continued) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ............ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The neighbor is identified by its System ID (6 octets), plus one octet to indicate the pseudonode number if the neighbor is on a LAN interface.
邻居通过其系统ID（6个八位字节）加上一个八位字节来标识，如果邻居在LAN接口上，则表示伪节点号。
The 1-octet flags field is interpreted as follows.
1-octet标志字段解释如下。
Flags (1 octet)
标志（1个八位组）
0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+
| Reserved |NA|
+--+--+--+--+--+--+--+--+
0 1 2 3 4 5 6 7
+--+--+--+--+--+--+--+--+
| Reserved |NA|
+--+--+--+--+--+--+--+--+
NA - Neighbor Address included.
NA-包括邻居地址。
The flags field currently contains one flag to indicate whether the IPv6 neighbor address is included (the NA bit is set to 1) or not included (the NA bit is set to 0).
flags字段当前包含一个标志，用于指示是否包括IPv6邻居地址（NA位设置为1）或不包括（NA位设置为0）。
Other bits in the flags field are reserved for future use. Any bits not understood by an implementation MUST be set to zero by the sender. If a router receives an IPv6 SRLG TLV with non-zero values for any bit that it does not understand, it MUST ignore the TLV (in other words, it does not use the TLV locally but floods the TLV unchanged to neighbors as normal).
标志字段中的其他位保留供将来使用。发送方必须将实现无法理解的任何位设置为零。如果路由器接收到一个IPv6 SRLG TLV，它不理解的任何位的值都不是零值，那么它必须忽略该TLV（换句话说，它不在本地使用TLV，而是像正常情况一样将TLV发送给邻居）。
Note that this rule for processing the flags octet allows for future extensibility of the IPv6 SRLG TLV. In particular, it allows alternative means of identifying the corresponding link to be added in the future. An implementation that does not understand such an extension will ignore the TLV rather than attempt to interpret the TLV incorrectly.
请注意，此处理标志八位字节的规则允许IPv6 SRLG TLV的未来扩展性。特别地，它允许在将来添加识别相应链路的替代方法。不理解这种扩展的实现将忽略TLV，而不是试图错误地解释TLV。
The length of this TLV is 24 + 4 * (number of SRLG values) + 16 (if the IPv6 neighbor address is included).
此TLV的长度为24+4*（SRLG值的数量）+16（如果包括IPv6邻居地址）。
To prevent an SRLG TLV and an IPv6 SRLG TLV in the same logical LSP from causing confusion of interpretation, the following rules are applied.
为防止同一逻辑LSP中的SRLG TLV和IPv6 SRLG TLV造成解释混乱，应用以下规则。
- The IPv6 SRLG TLV MAY occur more than once within the IS-IS logical LSP.
- IPv6 SRLG TLV可能在IS-IS逻辑LSP中出现多次。
- There MUST NOT be more than one IPv6 SRLG TLV for a given link.
- 对于给定的链路，不能有多个IPv6 SRLG TLV。
- The IPv6 SRLG TLV (type 139) MUST NOT be used to describe the SRLGs for a given link if it is possible to use the SRLG TLV (type 138).
- 如果可以使用SRLG TLV（类型138），则不得使用IPv6 SRLG TLV（类型139）来描述给定链路的SRLGs。
- If both an SRLG TLV and an IPv6 SRLG are received describing the SRLGs for the same link, the receiver MUST apply the SRLG TLV and ignore the IPv6 SRLG TLV.
- 如果同时收到描述同一链路的SRLG TLV和IPv6 SRLG，则接收方必须应用SRLG TLV并忽略IPv6 SRLG TLV。
In other words, if SRLGs are to be advertised for a link and if the Extended IS Reachability TLV describing a link contains IPv4 interface/neighbor address sub-TLVs or the link-local identifiers sub-TLV, then the SRLGs MUST be advertised in the SRLG TLV (type 138).
换句话说，如果要为链路通告SRLGs，并且如果描述链路的扩展IS可达性TLV包含IPv4接口/邻居地址子TLV或链路本地标识符子TLV，则必须在SRLGTLV中通告SRLGs（类型138）。
The IPv6 Global Interface Address TLV is TLV type 233. The TLV structure is identical to that of the IPv6 Interface Address TLV defined in [IPv6], but the semantics are different. In particular, the TLV is included in IIH PDUs for those interfaces using IPv6 TE extensions. The TLV contains global or unique-local IPv6 addresses assigned to the interface that is sending the Hello.
IPv6全局接口地址TLV是TLV类型233。TLV结构与[IPv6]中定义的IPv6接口地址TLV的结构相同，但语义不同。特别是，对于使用IPv6 TE扩展的接口，TLV包含在IIH PDU中。TLV包含分配给发送Hello的接口的全局或唯一本地IPv6地址。
The IPv6 Global Interface Address TLV is not used in LSPs.
LSP中未使用IPv6全局接口地址TLV。
This document raises no new security issues for IS-IS; for general security considerations for IS-IS, see [ISIS-AUTH].
本文件未对IS-IS提出新的安全问题；有关IS-IS的一般安全注意事项，请参阅[ISIS-AUTH]。
The IS-IS extensions described in this document allow the routing of GMPLS Label Switched Paths using IPv6 addressing through an IS-IS network. There are no migration issues introduced by the addition of this IPv6 TE routing information into an existing IPv4 GMPLS network. Migration of Label Switched Paths from IPv4 to IPv6 is an issue for GMPLS signaling and is outside the scope of this document.
本文档中描述的IS-IS扩展允许通过IS-IS网络使用IPv6寻址对GMPLS标签交换路径进行路由。将此IPv6 TE路由信息添加到现有IPv4 GMPLS网络中不会导致迁移问题。将标签交换路径从IPv4迁移到IPv6是GMPLS信令的一个问题，不在本文档的范围内。
This document defines the following new IS-IS TLV types that IANA has reflected in the IS-IS TLV code-point registry:
本文档定义了IANA在IS-IS TLV代码点注册表中反映的以下新IS-IS TLV类型：
Type Description IIH LSP SNP
---- ---------------------- --- --- ---
139 IPv6 SRLG TLV n y n
140 IPv6 TE Router ID n y n
233 IPv6 Global Interface y n n
Address TLV
Type Description IIH LSP SNP
---- ---------------------- --- --- ---
139 IPv6 SRLG TLV n y n
140 IPv6 TE Router ID n y n
233 IPv6 Global Interface y n n
Address TLV
This document also defines the following new sub-TLV types of top-level TLV 22 that IANA has reflected in the Sub-TLVs for TLV 22, 141, and 222 registry:
本文件还定义了IANA在TLV 22、141和222注册表子TLV中反映的顶级TLV 22的以下新子TLV类型：
Type Description 22 141 222 Length
---- ----------- -- --- --- ------
12 IPv6 Interface Address y y y 16
13 IPv6 Neighbor Address y y y 16
Type Description 22 141 222 Length
---- ----------- -- --- --- ------
12 IPv6 Interface Address y y y 16
13 IPv6 Neighbor Address y y y 16
[IS-IS] ISO, "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)", International Standard 10589: 2002, Second Edition, 2002.
[IS-IS]ISO，“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）”，国际标准10589:2002，第二版，2002年。
[IPv6] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, October 2008.
[IPv6]Hopps，C.，“使用IS-IS路由IPv6”，RFC 5308，2008年10月。
[TE] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008.
[TE]Li，T.和H.Smit，“交通工程的IS-IS扩展”，RFC 53052008年10月。
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
[关键词]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，1997年3月。
[ISIS-AUTH] Li, T. and R. Atkinson, "IS-IS Cryptographic Authentication", RFC 5304, October 2008.
[ISIS-AUTH]Li，T.和R.Atkinson，“IS-IS加密认证”，RFC 5304，2008年10月。
[GMPLS] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 5307, October 2008.
[GMPLS]Kompella，K.，Ed.，和Y.Rekhter，Ed.，“支持通用多协议标签交换（GMPLS）的IS-IS扩展”，RFC 5307，2008年10月。
[GMPLS-ROUTING] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4202, October 2005.
[GMPLS-ROUTING]Kompella，K.，Ed.，和Y.Rekhter，Ed.，“支持通用多协议标签交换（GMPLS）的路由扩展”，RFC 4202，2005年10月。
Authors' Addresses
作者地址
Jon Harrison Metaswitch Networks 100 Church Street Enfield EN2 6BQ U.K. Phone: +44 20 8366 1177 EMail: jon.harrison@metaswitch.com
乔恩哈里森MetaswitCH网络100教堂街恩菲尔德En2 6BQ英国电话：+ 44 20 20 8366电子邮件：乔恩。harrison@metaswitch.com
Jon Berger Metaswitch Networks 100 Church Street Enfield EN2 6BQ U.K. Phone: +44 20 8366 1177 EMail: jon.berger@metaswitch.com
乔恩伯杰MetaswitCH网络100教堂街恩菲尔德En2 6BQ英国电话：+ 44 20 20 8366电子邮件：乔恩。berger@metaswitch.com
Mike Bartlett Metaswitch Networks 100 Church Street Enfield EN2 6BQ U.K. Phone: +44 20 8366 1177 EMail: mike.bartlett@metaswitch.com
Mike Bartlett MetaswitCH网络100教堂街恩菲尔德En2 6BQ英国电话：+ 44 20 20 8366电子邮件：迈克。bartlett@metaswitch.com