Internet Engineering Task Force (IETF) J. Tantsura
Request for Comments: 8476 Apstra, Inc.
Category: Standards Track U. Chunduri
ISSN: 2070-1721 Huawei Technologies
S. Aldrin
Google, Inc.
P. Psenak
Cisco Systems
December 2018
Internet Engineering Task Force (IETF) J. Tantsura
Request for Comments: 8476 Apstra, Inc.
Category: Standards Track U. Chunduri
ISSN: 2070-1721 Huawei Technologies
S. Aldrin
Google, Inc.
P. Psenak
Cisco Systems
December 2018
Signaling Maximum SID Depth (MSD) Using OSPF
使用OSPF发送最大SID深度（MSD）信号
Abstract
摘要
This document defines a way for an Open Shortest Path First (OSPF) router to advertise multiple types of supported Maximum SID Depths (MSDs) at node and/or link granularity. Such advertisements allow entities (e.g., centralized controllers) to determine whether a particular Segment Identifier (SID) stack can be supported in a given network. This document only refers to the Signaling MSD as defined in RFC 8491, but it defines an encoding that can support other MSD types. Here, the term "OSPF" means both OSPFv2 and OSPFv3.
本文档定义了开放式最短路径优先（OSPF）路由器在节点和/或链路粒度上公布多种类型的受支持最大SID深度（MSDs）的方法。此类广告允许实体（例如，集中式控制器）确定特定的段标识符（SID）堆栈在给定网络中是否受支持。本文档仅参考RFC 8491中定义的信令MSD，但它定义了可支持其他MSD类型的编码。这里，术语“OSPF”是指OSPFv2和OSPFv3。
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 7841.
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 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8476.
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https://www.rfc-editor.org/info/rfc8476.
Copyright Notice
版权公告
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2018 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 (https://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(https://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. Terminology ................................................4
1.2. Requirements Language ......................................4
2. Node MSD Advertisement ..........................................5
3. Link MSD Sub-TLV ................................................6
4. Procedures for Defining and Using Node and Link MSD
Advertisements ..................................................7
5. IANA Considerations .............................................7
6. Security Considerations .........................................8
7. References ......................................................9
7.1. Normative References .......................................9
7.2. Informative References ....................................10
Acknowledgements ..................................................11
Contributors ......................................................11
Authors' Addresses ................................................11
1. Introduction ....................................................3
1.1. Terminology ................................................4
1.2. Requirements Language ......................................4
2. Node MSD Advertisement ..........................................5
3. Link MSD Sub-TLV ................................................6
4. Procedures for Defining and Using Node and Link MSD
Advertisements ..................................................7
5. IANA Considerations .............................................7
6. Security Considerations .........................................8
7. References ......................................................9
7.1. Normative References .......................................9
7.2. Informative References ....................................10
Acknowledgements ..................................................11
Contributors ......................................................11
Authors' Addresses ................................................11
When Segment Routing (SR) paths are computed by a centralized controller, it is critical that the controller learn the Maximum SID Depth (MSD) that can be imposed at each node/link on a given SR path. This ensures that the Segment Identifier (SID) stack depth of a computed path doesn't exceed the number of SIDs the node is capable of imposing.
当集中控制器计算段路由（SR）路径时，控制器了解可施加在给定SR路径上的每个节点/链路上的最大SID深度（MSD）是至关重要的。这可确保计算路径的段标识符（SID）堆栈深度不超过节点能够施加的SID数量。
[PCEP-EXT] defines how to signal MSD in the Path Computation Element Communication Protocol (PCEP). However, if PCEP is not supported/ configured on the head-end of an SR tunnel or a Binding-SID anchor node, and the controller does not participate in IGP routing, it has no way of learning the MSD of nodes and links. BGP-LS (Distribution of Link-State and TE Information Using BGP) [RFC7752] defines a way to expose topology and associated attributes and capabilities of the nodes in that topology to a centralized controller. MSD signaling by BGP-LS has been defined in [MSD-BGP]. Typically, BGP-LS is configured on a small number of nodes that do not necessarily act as head-ends. In order for BGP-LS to signal MSD for all the nodes and links in the network for which MSD is relevant, MSD capabilities SHOULD be advertised by every OSPF router in the network.
[PCEP-EXT]定义如何在路径计算元素通信协议（PCEP）中向MSD发送信号。但是，如果在SR隧道或绑定SID锚节点的前端不支持/配置PCEP，并且控制器不参与IGP路由，则无法了解节点和链路的MSD。BGP-LS（使用BGP分发链路状态和TE信息）[RFC7752]定义了一种向集中式控制器公开拓扑以及该拓扑中节点的相关属性和功能的方法。BGP-LS的MSD信令已在[MSD-BGP]中定义。通常，BGP-LS配置在少数不一定充当前端的节点上。为了让BGP-LS向网络中与MSD相关的所有节点和链路发送MSD信号，网络中的每个OSPF路由器都应公布MSD功能。
Other types of MSDs are known to be useful. For example, [ELC-ISIS] defines Entropy Readable Label Depth (ERLD), which is used by a head-end to insert an Entropy Label (EL) at a depth where it can be read by transit nodes.
已知其他类型的MSDs是有用的。例如，[ELC-ISIS]定义了熵可读标签深度（ERLD），前端使用该深度在传输节点可以读取的深度插入熵标签（EL）。
This document defines an extension to OSPF used to advertise one or more types of MSDs at node and/or link granularity. In the future, it is expected that new MSD-Types will be defined to signal additional capabilities, e.g., ELs, SIDs that can be imposed through recirculation, or SIDs associated with another data plane such as IPv6.
本文档定义了OSPF的扩展，用于在节点和/或链路粒度上公布一种或多种类型的MSDs。未来，预计将定义新的MSD类型，以显示附加功能，例如ELs、可通过再循环施加的SID或与另一个数据平面（如IPv6）关联的SID。
MSD advertisements MAY be useful even if SR itself is not enabled. For example, in a non-SR MPLS network, MSD defines the maximum label depth.
即使SR本身未启用，MSD广告也可能有用。例如，在非SR MPLS网络中，MSD定义最大标签深度。
This memo makes use of the terms defined in [RFC7770].
本备忘录使用了[RFC7770]中定义的术语。
BGP-LS: Distribution of Link-State and TE Information Using BGP
BGP-LS：使用BGP分发链路状态和TE信息
OSPF: Open Shortest Path First
开放最短路径优先
MSD: Maximum SID Depth - the number of SIDs supported by a node or a link on a node
MSD:最大SID深度—节点或节点上的链接支持的SID数
SID: Segment Identifier as defined in [RFC8402]
SID:[RFC8402]中定义的段标识符
Label Imposition: Imposition is the act of modifying and/or adding labels to the outgoing label stack associated with a packet. This includes:
标签粘贴：粘贴是修改和/或向与数据包相关的传出标签堆栈添加标签的行为。这包括：
* replacing the label at the top of the label stack with a new label
* 用新标签替换标签堆栈顶部的标签
* pushing one or more new labels onto the label stack
* 将一个或多个新标签推送到标签堆栈上
The number of labels imposed is then the sum of the number of labels that are replaced and the number of labels that are pushed. See [RFC3031] for further details.
然后，施加的标签数量是替换的标签数量和推送的标签数量之和。有关更多详细信息，请参见[RFC3031]。
PCEP: Path Computation Element Communication Protocol
PCEP：路径计算元素通信协议
SR: Segment Routing
SR：段路由
LSA: Link State Advertisement
链接状态广告
RI: Router Information
路由器信息
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
The Node MSD TLV within the body of the OSPF RI Opaque LSA [RFC7770] is defined to carry the provisioned SID depth of the router originating the RI LSA. Node MSD is the smallest MSD supported by the node on the set of interfaces configured for use by the advertising IGP instance. MSD values may be learned via a hardware API or may be provisioned.
OSPF RI不透明LSA[RFC7770]主体内的节点MSD TLV被定义为承载发起RI LSA的路由器的配置SID深度。节点MSD是该节点在为广告IGP实例使用而配置的一组接口上支持的最小MSD。MSD值可通过硬件API学习或设置。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Node MSD TLV
图1：节点MSD TLV
Type: 12
类型：12
Length: variable (multiple of 2 octets); represents the total length of the value field in octets.
长度：可变（2个八位字节的倍数）；表示值字段的总长度（以八位字节为单位）。
Value: consists of one or more pairs of a 1-octet MSD-Type and 1-octet MSD-Value.
值：由一对或多对1-octet MSD类型和1-octet MSD值组成。
MSD-Type: one of the values defined in the "IGP MSD-Types" registry defined in [RFC8491].
MSD类型：在[RFC8491]中定义的“IGP MSD类型”注册表中定义的值之一。
MSD-Value: a number in the range of 0-255. For all MSD-Types, 0 represents the lack of ability to impose an MSD stack of any depth; any other value represents that of the node. This value MUST represent the lowest value supported by any link configured for use by the advertising OSPF instance.
MSD值：0-255范围内的数字。对于所有MSD类型，0表示没有能力施加任何深度的MSD堆栈；任何其他值表示节点的值。此值必须表示为广告OSPF实例使用而配置的任何链接所支持的最低值。
This TLV is optional and is applicable to both OSPFv2 and OSPFv3. The scope of the advertisement is specific to the deployment.
该TLV是可选的，适用于OSPFv2和OSPFv3。播发的范围特定于部署。
When multiple Node MSD TLVs are received from a given router, the receiver MUST use the first occurrence of the TLV in the Router Information (RI) LSA. If the Node MSD TLV appears in multiple RI LSAs that have different flooding scopes, the Node MSD TLV in the RI LSA with the area-scoped flooding scope MUST be used. If the Node MSD TLV appears in multiple RI LSAs that have the same flooding scope, the Node MSD TLV in the RI LSA with the numerically smallest Instance ID MUST be used and other instances of the Node MSD TLV MUST be ignored. The RI LSA can be advertised at any of the defined
当从给定路由器接收到多个节点MSD TLV时，接收器必须使用路由器信息（RI）LSA中第一个出现的TLV。如果节点MSD TLV出现在具有不同泛洪作用域的多个RI LSA中，则必须使用具有区域范围泛洪作用域的RI LSA中的节点MSD TLV。如果节点MSD TLV出现在具有相同泛洪作用域的多个RI LSA中，则必须使用实例ID数值最小的RI LSA中的节点MSD TLV，并且必须忽略节点MSD TLV的其他实例。RI LSA可以在任何定义的
opaque flooding scopes (link, area, or Autonomous System (AS)). For the purpose of Node MSD TLV advertisement, area-scoped flooding is RECOMMENDED.
不透明泛洪范围（链路、区域或自治系统（AS））。对于节点MSD TLV广告，建议使用区域范围的泛洪。
The Link MSD sub-TLV is defined to carry the MSD of the interface associated with the link. MSD values may be learned via a hardware API or may be provisioned.
链路MSD子TLV定义为承载与链路相关联的接口的MSD。MSD值可通过硬件API学习或设置。
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type | MSD-Value | MSD-Type... | MSD-Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Link MSD Sub-TLV
图2：链接MSD子TLV
Type: For OSPFv2, the link-level MSD-Value is advertised as an optional sub-TLV of the OSPFv2 Extended Link TLV as defined in [RFC7684] and has a type of 6.
类型：对于OSPFv2，链路级MSD值作为[RFC7684]中定义的OSPFv2扩展链路TLV的可选子TLV公布，其类型为6。
For OSPFv3, the link-level MSD-Value is advertised as an optional sub-TLV of the E-Router-LSA TLV as defined in [RFC8362] and has a type of 9.
对于OSPFv3，链路级MSD值作为[RFC8362]中定义的E-Router-LSA TLV的可选子TLV公布，其类型为9。
Length: variable; same as defined in Section 2.
长度：可变；与第2节中的定义相同。
Value: consists of one or more pairs of a 1-octet MSD-Type and 1-octet MSD-Value.
值：由一对或多对1-octet MSD类型和1-octet MSD值组成。
MSD-Type: one of the values defined in the "IGP MSD-Types" registry defined in [RFC8491].
MSD类型：在[RFC8491]中定义的“IGP MSD类型”注册表中定义的值之一。
The MSD-Value field contains the Link MSD of the router originating the corresponding LSA as specified for OSPFv2 and OSPFv3. The Link MSD is a number in the range of 0-255. For all MSD-Types, 0 represents the lack of ability to impose an MSD stack of any depth; any other value represents that of the particular link when used as an outgoing interface.
MSD值字段包含为OSPFv2和OSPFv3指定的发起相应LSA的路由器的链路MSD。链接MSD是一个范围为0-255的数字。对于所有MSD类型，0表示没有能力施加任何深度的MSD堆栈；当用作传出接口时，任何其他值表示特定链接的值。
If this sub-TLV is advertised multiple times for the same link in different OSPF Extended Link Opaque LSAs / E-Router-LSAs originated by the same OSPF router, the sub-TLV in the OSPFv2 Extended Link
如果该子TLV针对由同一OSPF路由器发起的不同OSPF扩展链路不透明LSA/E-Router-LSA中的同一链路多次播发，则OSPFv2扩展链路中的子TLV
Opaque LSA with the smallest Opaque ID or in the OSPFv3 E-Router-LSA with the smallest Link State ID MUST be used by receiving OSPF routers. This situation SHOULD be logged as an error.
接收OSPF路由器必须使用具有最小不透明ID的不透明LSA或在OSPFv3 E路由器中具有最小链路状态ID的不透明LSA。这种情况应记录为错误。
When Link MSD is present for a given MSD-Type, the value of the Link MSD MUST take precedence over the Node MSD. When a Link MSD-Type is not signaled but the Node MSD-Type is, then the Node MSD-Type value MUST be considered as the MSD value for that link.
当给定MSD类型存在链接MSD时，链接MSD的值必须优先于节点MSD。如果未通知链路MSD类型，但节点MSD类型为，则必须将节点MSD类型值视为该链路的MSD值。
In order to increase flooding efficiency, it is RECOMMENDED that routers with homogenous Link MSD values advertise just the Node MSD value.
为了提高泛洪效率，建议具有同质链路MSD值的路由器仅公布节点MSD值。
The meaning of the absence of both Node and Link MSD advertisements for a given MSD-Type is specific to the MSD-Type. Generally, it can only be inferred that the advertising node does not support advertisement of that MSD-Type. However, in some cases the lack of advertisement might imply that the functionality associated with the MSD-Type is not supported. Per [RFC8491], the correct interpretation MUST be specified when an MSD-Type is defined.
给定MSD类型中没有节点和链接MSD播发的含义特定于MSD类型。通常，只能推断广告节点不支持该MSD类型的广告。但是，在某些情况下，缺少广告可能意味着不支持与MSD类型关联的功能。根据[RFC8491]，定义MSD类型时，必须指定正确的解释。
This specification updates several existing OSPF registries.
本规范更新了几个现有的OSPF注册表。
IANA has allocated TLV type 12 from the "OSPF Router Information (RI) TLVs" registry as defined by [RFC7770].
IANA已从[RFC7770]定义的“OSPF路由器信息（RI）TLV”注册表中分配TLV类型12。
Value Description Reference
----- --------------- -------------
12 Node MSD This document
Value Description Reference
----- --------------- -------------
12 Node MSD This document
Figure 3: RI Node MSD
图3:RI节点MSD
IANA has allocated sub-TLV type 6 from the "OSPFv2 Extended Link TLV Sub-TLVs" registry.
IANA已从“OSPFv2扩展链路TLV子TLV”注册表中分配子TLV类型6。
Value Description Reference
----- --------------- -------------
6 OSPFv2 Link MSD This document
Value Description Reference
----- --------------- -------------
6 OSPFv2 Link MSD This document
Figure 4: OSPFv2 Link MSD
图4:OSPFv2链路MSD
IANA has allocated sub-TLV type 9 from the "OSPFv3 Extended-LSA Sub-TLVs" registry.
IANA已从“OSPFv3扩展LSA子TLV”注册表中分配子TLV类型9。
Value Description Reference
----- --------------- -------------
9 OSPFv3 Link MSD This document
Value Description Reference
----- --------------- -------------
9 OSPFv3 Link MSD This document
Figure 5: OSPFv3 Link MSD
图5:OSPFv3链路MSD
Security concerns for OSPF are addressed in [RFC7474], [RFC4552], and [RFC7166]. Further security analysis for the OSPF protocol is done in [RFC6863]. Security considerations as specified by [RFC7770], [RFC7684], and [RFC8362] are applicable to this document.
[RFC7474]、[RFC4552]和[RFC7166]中阐述了OSPF的安全问题。[RFC6863]中对OSPF协议进行了进一步的安全性分析。[RFC7770]、[RFC7684]和[RFC8362]规定的安全注意事项适用于本文件。
Implementations MUST ensure that malformed TLVs and sub-TLVs defined in this document are detected and do not provide a vulnerability for attackers to crash the OSPF router or routing process. Reception of malformed TLVs or sub-TLVs SHOULD be counted and/or logged for further analysis. Logging of malformed TLVs and sub-TLVs SHOULD be rate-limited to prevent a Denial-of-Service (DoS) attack (distributed or otherwise) from overloading the OSPF control plane.
实施必须确保检测到本文档中定义的格式错误的TLV和子TLV，并且不会为攻击者提供使OSPF路由器或路由进程崩溃的漏洞。应统计和/或记录错误TLV或子TLV的接收情况，以便进一步分析。对格式错误的TLV和子TLV的记录应进行速率限制，以防止拒绝服务（DoS）攻击（分布式或其他）使OSPF控制平面过载。
Advertisement of an incorrect MSD value may have negative consequences. If the value is smaller than supported, path computation may fail to compute a viable path. If the value is larger than supported, an attempt to instantiate a path that can't be supported by the head-end (the node performing the SID imposition) may occur.
公布不正确的MSD值可能会产生负面后果。如果该值小于支持的值，则路径计算可能无法计算可行路径。如果该值大于支持的值，则可能会尝试实例化头端（执行SID强制的节点）不支持的路径。
The presence of this information may also inform an attacker of how to induce any of the aforementioned conditions.
此信息的存在还可能会告知攻击者如何诱发上述任何情况。
There's no DoS risk specific to this extension, and it is not vulnerable to replay attacks.
此扩展没有特定的DoS风险，并且不易受到重播攻击。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <https://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<https://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, DOI 10.17487/RFC3031, January 2001, <https://www.rfc-editor.org/info/rfc3031>.
[RFC3031]Rosen，E.，Viswanathan，A.，和R.Callon，“多协议标签交换体系结构”，RFC 3031，DOI 10.17487/RFC3031，2001年1月<https://www.rfc-editor.org/info/rfc3031>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7684]Psenak，P.，Gredler，H.，Shakir，R.，Henderickx，W.，Tantsura，J.，和A.Lindem，“OSPFv2前缀/链接属性广告”，RFC 7684，DOI 10.17487/RFC7684，2015年11月<https://www.rfc-editor.org/info/rfc7684>.
[RFC7770] Lindem, A., Ed., Shen, N., Vasseur, JP., Aggarwal, R., and S. Shaffer, "Extensions to OSPF for Advertising Optional Router Capabilities", RFC 7770, DOI 10.17487/RFC7770, February 2016, <https://www.rfc-editor.org/info/rfc7770>.
[RFC7770]Lindem，A.，Ed.，Shen，N.，Vasseur，JP.，Aggarwal，R.，和S.Shaffer，“用于宣传可选路由器功能的OSPF扩展”，RFC 7770，DOI 10.17487/RFC7770，2016年2月<https://www.rfc-editor.org/info/rfc7770>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8174]Leiba，B.，“RFC 2119关键词中大写与小写的歧义”，BCP 14，RFC 8174，DOI 10.17487/RFC8174，2017年5月<https://www.rfc-editor.org/info/rfc8174>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and F. Baker, "OSPFv3 Link State Advertisement (LSA) Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 2018, <https://www.rfc-editor.org/info/rfc8362>.
[RFC8362]Lindem，A.，Roy，A.，Goethals，D.，Reddy Vallem，V.，和F.Baker，“OSPFv3链路状态广告（LSA）可扩展性”，RFC 8362，DOI 10.17487/RFC8362，2018年4月<https://www.rfc-editor.org/info/rfc8362>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8402]Filsfils，C.，Ed.，Previdi，S.，Ed.，Ginsberg，L.，Decarene，B.，Litkowski，S.，和R.Shakir，“段路由架构”，RFC 8402，DOI 10.17487/RFC8402，2018年7月<https://www.rfc-editor.org/info/rfc8402>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491, DOI 10.17487/RFC8491, November 2018, <https://www.rfc-editor.org/info/rfc8491>.
[RFC8491]Tantsura，J.，Chunduri，U.，Aldrin，S.，和L.Ginsberg，“使用IS-IS发出最大SID深度（MSD）信号”，RFC 8491，DOI 10.17487/RFC8491，2018年11月<https://www.rfc-editor.org/info/rfc8491>.
[ELC-ISIS] Xu, X., Kini, S., Sivabalan, S., Filsfils, C., and S. Litkowski, "Signaling Entropy Label Capability and Entropy Readable Label-stack Depth Using OSPF", Work in Progress, draft-ietf-ospf-mpls-elc-07, September 2018.
[ELC-ISIS]Xu，X.，Kini，S.，Sivabalan，S.，Filsfils，C.，和S.Litkowski，“使用OSPF的信号熵标签能力和熵可读标签堆栈深度”，正在进行的工作，草稿-ietf-OSPF-mpls-ELC-07，2018年9月。
[MSD-BGP] Tantsura, J., Chunduri, U., Mirsky, G., and S. Sivabalan, "Signaling MSD (Maximum SID Depth) using Border Gateway Protocol Link-State", Work in Progress, draft-ietf-idr-bgp-ls-segment-routing-msd-02, August 2018.
[MSD-BGP]Tantsura，J.，Chunduri，U.，Mirsky，G.，和S.Sivabalan，“使用边界网关协议链路状态发送MSD（最大SID深度），正在进行的工作，草案-ietf-idr-BGP-ls-segment-routing-MSD-02，2018年8月。
[PCEP-EXT] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W., and J. Hardwick, "PCEP Extensions for Segment Routing", Work in Progress, draft-ietf-pce-segment-routing-14, October 2018.
[PCEP-EXT]Sivabalan，S.，Filsfils，C.，Tantsura，J.，Henderickx，W.，和J.Hardwick，“分段布线的PCEP扩展”，正在进行的工作，草案-ietf-pce-Segment-Routing-14，2018年10月。
[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, <https://www.rfc-editor.org/info/rfc4552>.
[RFC4552]Gupta，M.和N.Melam，“OSPFv3的认证/保密”，RFC 4552，DOI 10.17487/RFC4552，2006年6月<https://www.rfc-editor.org/info/rfc4552>.
[RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6863, DOI 10.17487/RFC6863, March 2013, <https://www.rfc-editor.org/info/rfc6863>.
[RFC6863]Hartman，S.和D.Zhang，“根据路由协议键控和认证（KARP）设计指南分析OSPF安全性”，RFC 6863，DOI 10.17487/RFC6863，2013年3月<https://www.rfc-editor.org/info/rfc6863>.
[RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting Authentication Trailer for OSPFv3", RFC 7166, DOI 10.17487/RFC7166, March 2014, <https://www.rfc-editor.org/info/rfc7166>.
[RFC7166]Bhatia，M.，Manral，V.，和A.Lindem，“OSPFv3的支持认证拖车”，RFC 7166，DOI 10.17487/RFC7166，2014年3月<https://www.rfc-editor.org/info/rfc7166>.
[RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed., "Security Extension for OSPFv2 When Using Manual Key Management", RFC 7474, DOI 10.17487/RFC7474, April 2015, <https://www.rfc-editor.org/info/rfc7474>.
[RFC7474]Bhatia，M.，Hartman，S.，Zhang，D.，和A.Lindem，Ed.，“使用手动密钥管理时OSPFv2的安全扩展”，RFC 7474，DOI 10.17487/RFC7474，2015年4月<https://www.rfc-editor.org/info/rfc7474>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, <https://www.rfc-editor.org/info/rfc7752>.
[RFC7752]Gredler，H.，Ed.，Medved，J.，Previdi，S.，Farrel，A.，和S.Ray，“使用BGP的链路状态和流量工程（TE）信息的北向分布”，RFC 7752，DOI 10.17487/RFC7752，2016年3月<https://www.rfc-editor.org/info/rfc7752>.
Acknowledgements
致谢
The authors would like to thank Acee Lindem, Ketan Talaulikar, Tal Mizrahi, Stephane Litkowski, and Bruno Decraene for their reviews and valuable comments.
作者要感谢Acee Lindem、Ketan Talaulikar、Tal Mizrahi、Stephane Litkowski和Bruno DeClaene的评论和宝贵意见。
Contributors
贡献者
The following person contributed to this document:
以下人士对本文件作出了贡献：
Les Ginsberg
莱斯金斯伯格酒店
Email: ginsberg@cisco.com
Email: ginsberg@cisco.com
Authors' Addresses
作者地址
Jeff Tantsura Apstra, Inc.
杰夫·坦特拉飞天公司。
Email: jefftant.ietf@gmail.com
Email: jefftant.ietf@gmail.com
Uma Chunduri Huawei Technologies
Uma Chunduri华为技术有限公司
Email: uma.chunduri@huawei.com
Email: uma.chunduri@huawei.com
Sam Aldrin Google, Inc.
山姆·奥尔德林谷歌公司。
Email: aldrin.ietf@gmail.com
Email: aldrin.ietf@gmail.com
Peter Psenak Cisco Systems
彼得·普塞纳克思科系统公司
Email: ppsenak@cisco.com
Email: ppsenak@cisco.com