Network Working Group P. Pillay-Esnault
Request for Comments: 5187 Cisco Systems
Category: Standards Track A. Lindem
Redback Networks
June 2008
Network Working Group P. Pillay-Esnault
Request for Comments: 5187 Cisco Systems
Category: Standards Track A. Lindem
Redback Networks
June 2008
OSPFv3 Graceful Restart
OSPFv3优雅重启
Status of This Memo
关于下段备忘
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Abstract
摘要
This document describes the OSPFv3 graceful restart. The OSPFv3 graceful restart is identical to that of OSPFv2 except for the differences described in this document. These differences include the format of the grace Link State Advertisements (LSAs) and other considerations.
本文档描述了OSPFv3的优雅重启。OSPFv3优雅重启与OSPFv2相同，但本文档中描述的不同之处除外。这些差异包括宽限链接状态广告（LSA）的格式和其他注意事项。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Grace Link State Advertisement . . . . . . . . . . . . . . . . 2
2.1. Grace LSA - LS Type . . . . . . . . . . . . . . . . . . . . 2
2.2. Grace LSA Format . . . . . . . . . . . . . . . . . . . . . 3
3. Additional Considerations for OSPFv3 Graceful Restart . . . . . 4
3.1. Preservation of LSA ID to Prefix Correspondence . . . . . . 4
3.2. Preservation of Interface IDs for Link-LSAs,
Network-LSAs, and Router-LSAs . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 6
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Grace Link State Advertisement . . . . . . . . . . . . . . . . 2
2.1. Grace LSA - LS Type . . . . . . . . . . . . . . . . . . . . 2
2.2. Grace LSA Format . . . . . . . . . . . . . . . . . . . . . 3
3. Additional Considerations for OSPFv3 Graceful Restart . . . . . 4
3.1. Preservation of LSA ID to Prefix Correspondence . . . . . . 4
3.2. Preservation of Interface IDs for Link-LSAs,
Network-LSAs, and Router-LSAs . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 6
Graceful OSPF restart [GRACE] describes a mechanism to restart the control plane of an OSPFv2 [OSPFv2] router that still has its forwarding plane intact with a minimum of disruption to the network.
优雅的OSPF重启[GRACE]描述了一种机制，用于重启OSPFv2[OSPFv2]路由器的控制平面，该路由器的转发平面保持完整，对网络的中断最小。
In general, the methods described in [GRACE] work for OSPFv3 [OSPFv3] as well. However, OSPFv3 will use a grace-LSA with a different format to signal that a router is initiating (or is about to initiate) a graceful restart. This document describes other OSPFv3 differences as well.
一般来说，[GRACE]中描述的方法也适用于OSPFv3[OSPFv3]。然而，OSPFv3将使用不同格式的grace LSA来表示路由器正在启动（或即将启动）正常重启。本文档还描述了OSPFv3的其他差异。
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 [RFC2119].
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[RFC2119]中所述进行解释。
An OSPFv3 router initiating a graceful restart of its OSPFv3 software originates grace-LSAs. A grace-LSA requests that the router's neighbors aid in its graceful restart by continuing to advertise the router as fully adjacent during the specified grace period. The grace-LSA contains the restarting router grace-period and the reason code indicating the reason for the graceful restart.
OSPFv3路由器启动其OSPFv3软件的正常重启时，会启动LSA。宽限LSA请求路由器的邻居通过在指定的宽限期内继续将路由器公告为完全相邻来帮助其正常重启。宽限LSA包含重新启动路由器宽限期和指示正常重新启动原因的原因代码。
In OSPFv3 (refer to section 2.11 of [OSPFv3]), neighboring routers on any link are always identified by their router IDs. This contrasts with the OSPFv2 behavior where neighbors on point-to-point networks and virtual links are identified by their Router IDs, while neighbors on broadcast, Non-Broadcast Multi-Access (NBMA), and point-to-multipoint links are identified by their IPv4 interface addresses. Consequently, there is no requirement for the router-address TLV [GRACE] for OSPFv3 graceful restart.
在OSPFv3中（参考[OSPFv3]的第2.11节），任何链路上的相邻路由器总是通过其路由器ID进行标识。这与OSPFv2行为形成对比，在OSPFv2行为中，点到点网络和虚拟链路上的邻居由其路由器ID标识，而广播、非广播多址（NBMA）和点到多点链路上的邻居由其IPv4接口地址标识。因此，OSPFv3正常重启不需要路由器地址TLV[GRACE]。
The TLV formats of the grace-LSA described in [GRACE] remain unchanged.
[grace]中描述的grace LSA的TLV格式保持不变。
A grace-LSA is defined as an LSA with the LS type equal to 0x000b.
宽限LSA定义为LS类型等于0x000b的LSA。
LSA function code LS Type Description
------------------------------------------
11 0x000b GRACE-LSA
LSA function code LS Type Description
------------------------------------------
11 0x000b GRACE-LSA
Grace-LSA Type and Function Code
Grace LSA类型和功能代码
The S2-bit and S1-bit are set to 0 to indicate link-local flooding scope. The U-bit is set to 0 since it isn't applicable to LSAs with link-local flooding scope.
S2位和S1位设置为0，以指示链路局部泛洪范围。U位设置为0，因为它不适用于具有链路本地泛洪作用域的LSA。
The format of a grace LSA is:
宽限LSA的格式为：
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age |0|0|0| 11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link State ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age |0|0|0| 11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link State ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
Grace-LSA Format
格雷斯LSA格式
The Link State ID of a grace-LSA in OSPFv3 is the Interface ID of the interface originating the LSA.
OSPFv3中grace LSA的链路状态ID是发起LSA的接口的接口ID。
The format of each TLV is:
每个TLV的格式为：
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Format
TLV格式
Grace-LSA TLVs are formatted according to section 2.3.2 of [OSPF-TE].
Grace LSA TLV根据[OSPF-TE]第2.3.2节进行格式化。
The following is the list of TLVs that can appear in the body of a grace-LSA.
以下是grace LSA主体中可能出现的TLV列表。
Grace Period (Type=1, Length=4). The number of seconds that the router's neighbors should continue to advertise the router as fully adjacent, regardless of the state of database synchronization between the router and its neighbors. This TLV MUST always appear in a grace-LSA.
宽限期（类型=1，长度=4）。无论路由器与其邻居之间的数据库同步状态如何，路由器的邻居应继续将路由器公告为完全相邻的秒数。此TLV必须始终显示在宽限LSA中。
Graceful restart reason (Type=2, Length=1). Encodes the reason for the router restart, as one of the following: 0 (unknown), 1 (software restart), 2 (software reload/upgrade), or 3 (switch to redundant control processor). This TLV MUST always appear in a grace-LSA.
重新启动原因（类型=2，长度=1）。将路由器重新启动的原因编码为以下原因之一：0（未知）、1（软件重新启动）、2（软件重新加载/升级）或3（切换到冗余控制处理器）。此TLV必须始终显示在宽限LSA中。
This section describes OSPFv3 unique considerations in addition to those described in [GRACE].
除[GRACE]中所述的注意事项外，本节还介绍了OSPFv3的独特注意事项。
In OSPFv2, there is a direct correspondence between summary and external LSA IDs and the prefixes being advertised. However, in OSPFv3, the LSA ID for inter-area prefix LSAs and external LSAs is simply an unsigned 32-bit integer. Hence, to avoid network churn during graceful restart, the restarting router MUST preserve the LSA ID to prefix correspondence across graceful restarts.
在OSPFv2中，摘要和外部LSA ID以及所通告的前缀之间存在直接对应关系。然而，在OSPFv3中，区域间前缀LSA和外部LSA的LSA ID只是一个无符号32位整数。因此，为了避免优雅重启期间的网络混乱，重启路由器必须保留LSA ID，以便在优雅重启期间为对应关系添加前缀。
3.2. Preservation of Interface IDs for Link-LSAs, Network-LSAs, and Router-LSAs
3.2. 保存链路LSA、网络LSA和路由器LSA的接口ID
In OSPFv3, the LSA ID for Link-LSAs and Network-LSAs and link descriptions in Router-LSAs map to their corresponding Interface ID. Changes in the Interface ID during graceful restart will result in a mismatch between the restarting router's pre-restart LSAs and its neighbor adjacency state. These disparities will cause the graceful restart to terminate prematurely.
在OSPFv3中，链路LSA和网络LSA的LSA ID以及路由器LSA中的链路描述映射到它们相应的接口ID。在正常重启期间，接口ID的更改将导致重启路由器的预重启LSA与其相邻状态不匹配。这些差异将导致重新启动过早终止。
Synchronizing Interface ID changes between neighbors is possible. However, placing the burden on the restarting router to preserve Interface IDs across restarts provides for a more robust, more deterministic, and simpler mechanism. Therefore, the OSPFv3 Interface ID, as described in section 3.1.2 of [OSPFv3], MUST be preserved by the restarting router across restarts.
可以在邻居之间同步接口ID更改。然而，将重新启动路由器的负担放在跨重新启动保留接口ID上，提供了更健壮、更确定和更简单的机制。因此，[OSPFv3]第3.1.2节中所述的OSPFv3接口ID必须由重启路由器在重启期间保留。
Many implementations currently use the interface's MIB-II IfIndex [MIB-INTF] for Interface ID. The persistence of Interface ID across reboots is described in section 3.1.5 of [MIB-PERS].
许多实现目前使用接口的MIB-II IfIndex[MIB-INTF]作为接口ID。接口ID在重新启动期间的持久性在[MIB-PERS]的第3.1.5节中进行了描述。
[OSPFv3-AUTH] relies on manual key distribution which precludes the use of replay protection that utilizes sequence numbers. The replay of an OSPF Link-Update containing a grace-LSA would allow an attacker to deceive neighboring routers into believing that a router that has been taken out of service (either intentionally or via a malicious action by the same attacker) is still active and is in the process of graceful restart. However, this attack is much more difficult than the obvious replay of standard OSPFv3 hello packets to accomplish the same thing by keeping the adjacency up. Since hello packets are sent more predictably and knowledge of the key is not required, the risk added by OSPFv3 graceful restart is insignificant. Hence, this document does not raise any new security concerns other than those covered in [OSPFv3], [OSPFv3-AUTH], and [GRACE].
[OSPFv3 AUTH]依赖于手动密钥分发，从而排除了使用序列号的重播保护。重播包含宽限LSA的OSPF链路更新将允许攻击者欺骗相邻路由器，使其相信已停止服务（无论是有意还是通过同一攻击者的恶意操作）的路由器仍处于活动状态，并且正在正常重启过程中。然而，这种攻击比标准OSPFv3 hello数据包的明显重放要困难得多，要通过保持邻接来完成同样的任务。由于hello数据包的发送更加可预测，并且不需要知道密钥，因此OSPFv3优雅重启所增加的风险是微不足道的。因此，除了[OSPFv3]、[OSPFv3 AUTH]和[GRACE]中涉及的安全问题外，本文件不会提出任何新的安全问题。
A new LSA function code has been assigned for the OSPFv3 grace-LSA. The assignment of 0x000b has been made in the "OSPFv3 LSA Function Codes" sub-registry of the "Open Shortest Path First v3 (OSPFv3) Parameters" registry. OSPFv3 grace-LSA TLVs and sub-TLVs use the "OSPFv2 Grace LSA Top Level TLV" IANA sub-registry of the "Open Shortest Path First v2 (OSPFv2) Parameters" registry.
已为OSPFv3 grace LSA分配了新的LSA功能代码。0x000b的分配已在“开放最短路径优先v3（OSPFv3）参数”注册表的“OSPFv3 LSA功能代码”子注册表中进行。OSPFv3 grace LSA TLV和子TLV使用“开放最短路径优先v2（OSPFv2）参数”注册表的“OSPFv2 grace LSA顶级TLV”IANA子注册表。
Many thanks to Kireeti Kompella, Les Ginsberg, and David Ward with whom much of this was discussed. The authors also wish to thank Kunihiro Ishiguro and Vivek Dubey for their comments.
非常感谢Kireeti Kompella、Les Ginsberg和David Ward，他们讨论了这一问题。作者还希望感谢石黑邦彦和杜比的评论。
This document was produced using Marshall Rose's xml2rfc tool.
本文档是使用Marshall Rose的xml2rfc工具生成的。
[GRACE] Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF Restart", RFC 3623, November 2003.
[GRACE]Moy，J.，Pillay Esnault，P.，和A.Lindem，“优雅的OSPF重启”，RFC 36232003年11月。
[OSPF-TE] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering Extensions to OSPF", RFC 3630, September 2003.
[OSPF-TE]Katz，D.，Yeung，D.，和K.Kompella，“OSPF的交通工程扩展”，RFC 3630，2003年9月。
[OSPFv2] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[OSPFv2]Moy，J.，“OSPF版本2”，STD 54，RFC 23281998年4月。
[OSPFv3] Moy, J., Ferguson, D., and R. Coltun, "OSPF for IPv6", RFC 2740, March 1997.
[OSPFv3]Moy，J.，Ferguson，D.，和R.Coltun，“IPv6的OSPF”，RFC 27401997年3月。
[RFC2119] Bradner, S., "Key words for use in RFC's 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。
[MIB-INTF] McCloghrie, K. and M. Rose, "Management Information Base for network management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, March 1991.
[MIB-INTF]McCloghrie，K.和M.Rose，“基于TCP/IP的互联网网络管理的管理信息库：MIB-II”，STD 17，RFC 1213，1991年3月。
[MIB-PERS] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, June 2000.
[MIB-PERS]McCloghrie，K.和F.Kastenholz，“接口组MIB”，RFC 28632000年6月。
[OSPFv3-AUTH] Gupta, M. and N. Melam, "Authentication/ Confidentiality for OSPFv3", RFC 4552, June 2006.
[OSPFv3认证]Gupta，M.和N.Melam，“OSPFv3的认证/保密”，RFC 45522006年6月。
Authors' Addresses
作者地址
Padma Pillay-Esnault Cisco Systems 3750 Cisco Way San Jose, CA 95134 USA
美国加利福尼亚州圣何塞市思科路3750号，邮编95134
EMail: ppe@cisco.com
EMail: ppe@cisco.com
Acee Lindem Redback Networks 102 Carric Bend Court Cary, NC 27519 USA
美国北卡罗来纳州卡里克本德法院102号Acee Lindem Redback Networks 27519
EMail: acee@redback.com
EMail: acee@redback.com
Full Copyright Statement
完整版权声明
Copyright (C) The IETF Trust (2008).
版权所有（C）IETF信托基金（2008年）。
This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.
本文件受BCP 78中包含的权利、许可和限制的约束，除其中规定外，作者保留其所有权利。
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
本文件及其包含的信息以“原样”为基础提供，贡献者、他/她所代表或赞助的组织（如有）、互联网协会、IETF信托基金和互联网工程任务组不承担任何明示或暗示的担保，包括但不限于任何保证，即使用本文中的信息不会侵犯任何权利，或对适销性或特定用途适用性的任何默示保证。
Intellectual Property
知识产权
The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.
IETF对可能声称与本文件所述技术的实施或使用有关的任何知识产权或其他权利的有效性或范围，或此类权利下的任何许可可能或可能不可用的程度，不采取任何立场；它也不表示它已作出任何独立努力来确定任何此类权利。有关RFC文件中权利的程序信息，请参见BCP 78和BCP 79。
Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.
向IETF秘书处披露的知识产权副本和任何许可证保证，或本规范实施者或用户试图获得使用此类专有权利的一般许可证或许可的结果，可从IETF在线知识产权存储库获取，网址为http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.
IETF邀请任何相关方提请其注意任何版权、专利或专利申请，或其他可能涵盖实施本标准所需技术的专有权利。请将信息发送至IETF的IETF-ipr@ietf.org.