Network Working Group S. Knight
Request for Comments: 2338 D. Weaver
Category: Standards Track Ascend Communications, Inc.
D. Whipple
Microsoft, Inc.
R. Hinden
D. Mitzel
P. Hunt
Nokia
P. Higginson
M. Shand
Digital Equipment Corp.
A. Lindem
IBM Corporation
April 1998
Network Working Group S. Knight
Request for Comments: 2338 D. Weaver
Category: Standards Track Ascend Communications, Inc.
D. Whipple
Microsoft, Inc.
R. Hinden
D. Mitzel
P. Hunt
Nokia
P. Higginson
M. Shand
Digital Equipment Corp.
A. Lindem
IBM Corporation
April 1998
Virtual Router Redundancy Protocol
虚拟路由器冗余协议
Status of this Memo
本备忘录的状况
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。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1998). All Rights Reserved.
版权所有（C）互联网协会（1998年）。版权所有。
Abstract
摘要
This memo defines the Virtual Router Redundancy Protocol (VRRP). VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IP address(es) associated with a virtual router is called the Master, and forwards packets sent to these IP addresses. The election process provides dynamic fail over in the forwarding responsibility should the Master become unavailable. This allows any of the virtual router IP addresses on the LAN to be used as the default first hop router by end-hosts. The advantage gained from using VRRP is a higher availability default path without requiring configuration of dynamic routing or router discovery protocols on every end-host.
本备忘录定义了虚拟路由器冗余协议（VRRP）。VRRP指定一个选择协议，该协议动态地将虚拟路由器的责任分配给LAN上的一个VRRP路由器。控制与虚拟路由器关联的IP地址的VRRP路由器称为主路由器，并转发发送到这些IP地址的数据包。如果主机不可用，选择过程在转发责任中提供动态故障切换。这允许局域网上的任何虚拟路由器IP地址被终端主机用作默认的第一跳路由器。使用VRRP的优点是，无需在每个终端主机上配置动态路由或路由器发现协议，即可获得更高的可用性默认路径。
Table of Contents
目录
1. Introduction...............................................2
2. Required Features..........................................5
3. VRRP Overview..............................................6
4. Sample Configurations......................................8
5. Protocol...................................................9
5.1 VRRP Packet Format....................................10
5.2 IP Field Descriptions.................................10
5.3 VRRP Field Descriptions...............................11
6. Protocol State Machine....................................13
6.1 Parameters............................................13
6.2 Timers................................................15
6.3 State Transition Diagram..............................15
6.4 State Descriptions....................................15
7. Sending and Receiving VRRP Packets........................18
7.1 Receiving VRRP Packets................................18
7.2 Transmitting Packets..................................19
7.3 Virtual MAC Address...................................19
8. Operational Issues........................................20
8.1 ICMP Redirects........................................20
8.2 Host ARP Requests.....................................20
8.3 Proxy ARP.............................................20
9. Operation over FDDI and Token Ring........................21
9.1 Operation over FDDI...................................21
9.2 Operation over Token Ring.............................21
10. Security Considerations...................................23
10.1 No Authentication....................................23
10.2 Simple Text Password.................................23
10.3 IP Authentication Header.............................24
11. Acknowledgments...........................................24
12. References................................................24
13. Authors' Addresses........................................25
14. Full Copyright Statement..................................27
1. Introduction...............................................2
2. Required Features..........................................5
3. VRRP Overview..............................................6
4. Sample Configurations......................................8
5. Protocol...................................................9
5.1 VRRP Packet Format....................................10
5.2 IP Field Descriptions.................................10
5.3 VRRP Field Descriptions...............................11
6. Protocol State Machine....................................13
6.1 Parameters............................................13
6.2 Timers................................................15
6.3 State Transition Diagram..............................15
6.4 State Descriptions....................................15
7. Sending and Receiving VRRP Packets........................18
7.1 Receiving VRRP Packets................................18
7.2 Transmitting Packets..................................19
7.3 Virtual MAC Address...................................19
8. Operational Issues........................................20
8.1 ICMP Redirects........................................20
8.2 Host ARP Requests.....................................20
8.3 Proxy ARP.............................................20
9. Operation over FDDI and Token Ring........................21
9.1 Operation over FDDI...................................21
9.2 Operation over Token Ring.............................21
10. Security Considerations...................................23
10.1 No Authentication....................................23
10.2 Simple Text Password.................................23
10.3 IP Authentication Header.............................24
11. Acknowledgments...........................................24
12. References................................................24
13. Authors' Addresses........................................25
14. Full Copyright Statement..................................27
There are a number of methods that an end-host can use to determine its first hop router towards a particular IP destination. These include running (or snooping) a dynamic routing protocol such as Routing Information Protocol [RIP] or OSPF version 2 [OSPF], running an ICMP router discovery client [DISC] or using a statically configured default route.
终端主机可以使用多种方法来确定其朝向特定IP目的地的第一跳路由器。这些包括运行（或窥探）动态路由协议，如路由信息协议[RIP]或OSPF版本2[OSPF]，运行ICMP路由器发现客户端[DISC]，或使用静态配置的默认路由。
Running a dynamic routing protocol on every end-host may be infeasible for a number of reasons, including administrative overhead, processing overhead, security issues, or lack of a protocol implementation for some platforms. Neighbor or router discovery
由于许多原因，在每个终端主机上运行动态路由协议可能是不可行的，包括管理开销、处理开销、安全问题，或者某些平台缺少协议实现。邻居或路由器发现
protocols may require active participation by all hosts on a network, leading to large timer values to reduce protocol overhead in the face of large numbers of hosts. This can result in a significant delay in the detection of a lost (i.e., dead) neighbor, which may introduce unacceptably long "black hole" periods.
协议可能需要网络上所有主机的积极参与，从而导致较大的计时器值，以减少面对大量主机时的协议开销。这可能导致在检测丢失（即死亡）邻居时出现明显延迟，这可能会引入不可接受的长“黑洞”周期。
The use of a statically configured default route is quite popular; it minimizes configuration and processing overhead on the end-host and is supported by virtually every IP implementation. This mode of operation is likely to persist as dynamic host configuration protocols [DHCP] are deployed, which typically provide configuration for an end-host IP address and default gateway. However, this creates a single point of failure. Loss of the default router results in a catastrophic event, isolating all end-hosts that are unable to detect any alternate path that may be available.
使用静态配置的默认路由非常流行；它最大限度地减少了终端主机上的配置和处理开销，几乎每个IP实现都支持它。随着动态主机配置协议[DHCP]的部署，这种操作模式可能会持续下去，动态主机配置协议通常为终端主机IP地址和默认网关提供配置。但是，这会造成单点故障。丢失默认路由器会导致灾难性事件，隔离所有无法检测任何可用备用路径的终端主机。
The Virtual Router Redundancy Protocol (VRRP) is designed to eliminate the single point of failure inherent in the static default routed environment. VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router to one of the VRRP routers on a LAN. The VRRP router controlling the IP address(es) associated with a virtual router is called the Master, and forwards packets sent to these IP addresses. The election process provides dynamic fail-over in the forwarding responsibility should the Master become unavailable. Any of the virtual router's IP addresses on a LAN can then be used as the default first hop router by end-hosts. The advantage gained from using VRRP is a higher availability default path without requiring configuration of dynamic routing or router discovery protocols on every end-host.
虚拟路由器冗余协议（VRRP）旨在消除静态默认路由环境中固有的单点故障。VRRP指定一个选择协议，该协议动态地将虚拟路由器的责任分配给LAN上的一个VRRP路由器。控制与虚拟路由器关联的IP地址的VRRP路由器称为主路由器，并转发发送到这些IP地址的数据包。如果主机不可用，选择过程在转发责任中提供动态故障切换。局域网上任何虚拟路由器的IP地址都可以被终端主机用作默认的第一跳路由器。使用VRRP的优点是，无需在每个终端主机上配置动态路由或路由器发现协议，即可获得更高的可用性默认路径。
VRRP provides a function similar to a Cisco Systems, Inc. proprietary protocol named Hot Standby Router Protocol (HSRP) [HSRP] and to a Digital Equipment Corporation, Inc. proprietary protocol named IP Standby Protocol [IPSTB].
VRRP提供的功能类似于Cisco Systems，Inc.名为热备用路由器协议（HSRP）[HSRP]的专有协议和数字设备公司名为IP备用协议[IPSTB]的专有协议。
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].
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]中所述进行解释。
The IESG/IETF take no position regarding the validity or scope of any intellectual property right or other rights that might be claimed to pertain to the implementation or use of the technology, or the extent to which any license under such rights might or might not be available. See the IETF IPR web page at http://www.ietf.org/ipr.html for additional information.
IESG/IETF对可能声称与技术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。参见IETF IPR网页，网址为http://www.ietf.org/ipr.html 有关更多信息，请参阅。
The remainder of this document describes the features, design goals, and theory of operation of VRRP. The message formats, protocol processing rules and state machine that guarantee convergence to a single Virtual Router Master are presented. Finally, operational issues related to MAC address mapping, handling of ARP requests, generation of ICMP redirect messages, and security issues are addressed.
本文件的其余部分描述了VRRP的特点、设计目标和运行理论。介绍了保证收敛到单个虚拟路由器主机的消息格式、协议处理规则和状态机。最后，讨论了与MAC地址映射、ARP请求处理、ICMP重定向消息生成和安全问题相关的操作问题。
This protocol is intended for use with IPv4 routers only. A separate specification will be produced if it is decided that similar functionality is desirable in an IPv6 environment.
此协议仅用于IPv4路由器。如果决定在IPv6环境中需要类似的功能，则将生成单独的规范。
VRRP Router A router running the Virtual Router Redundancy Protocol. It may participate in one or more virtual routers.
VRRP路由器运行虚拟路由器冗余协议的路由器。它可以参与一个或多个虚拟路由器。
Virtual Router An abstract object managed by VRRP that acts as a default router for hosts on a shared LAN. It consists of a Virtual Router Identifier and a set of associated IP address(es) across a common LAN. A VRRP Router may backup one or more virtual routers.
虚拟路由器由VRRP管理的抽象对象，用作共享LAN上主机的默认路由器。它由一个虚拟路由器标识符和一组跨公共LAN的关联IP地址组成。VRRP路由器可以备份一个或多个虚拟路由器。
IP Address Owner The VRRP router that has the virtual router's IP address(es) as real interface address(es). This is the router that, when up, will respond to packets addressed to one of these IP addresses for ICMP pings, TCP connections, etc.
IP地址所有者将虚拟路由器的IP地址作为实际接口地址的VRRP路由器。这是一个路由器，当它启动时，它将响应发送到其中一个IP地址的数据包，用于ICMP ping、TCP连接等。
Primary IP Address An IP address selected from the set of real interface addresses. One possible selection algorithm is to always select the first address. VRRP advertisements are always sent using the primary IP address as the source of the IP packet.
主IP地址从实际接口地址集中选择的IP地址。一种可能的选择算法是始终选择第一个地址。VRRP广告始终使用主IP地址作为IP数据包的源发送。
Virtual Router Master The VRRP router that is assuming the responsibility of forwarding packets sent to the IP address(es) associated with the virtual router, and answering ARP requests for these IP addresses. Note that if the IP address owner is available, then it will always become the Master.
虚拟路由器主控VRRP路由器，该路由器负责转发发送到与虚拟路由器关联的IP地址的数据包，并回答这些IP地址的ARP请求。请注意，如果IP地址所有者可用，则它将始终成为主地址。
Virtual Router Backup The set of VRRP routers available to assume forwarding responsibility for a virtual router should the current Master fail.
虚拟路由器备份如果当前主路由器出现故障，可用于承担虚拟路由器转发责任的一组VRRP路由器。
This section outlines the set of features that were considered mandatory and that guided the design of VRRP.
本节概述了被认为是强制性的、指导VRRP设计的一系列功能。
Backup of IP addresses is the primary function of the Virtual Router Redundancy Protocol. While providing election of a Virtual Router Master and the additional functionality described below, the protocol should strive to:
IP地址备份是虚拟路由器冗余协议的主要功能。在提供虚拟路由器主机的选择和下面描述的附加功能的同时，协议应努力：
- Minimize the duration of black holes. - Minimize the steady state bandwidth overhead and processing complexity. - Function over a wide variety of multiaccess LAN technologies capable of supporting IP traffic. - Provide for election of multiple virtual routers on a network for load balancing - Support of multiple logical IP subnets on a single LAN segment.
- 尽量减少黑洞的持续时间最小化稳态带宽开销和处理复杂性。-可在多种支持IP通信的多址LAN技术上运行。-提供在网络上选择多个虚拟路由器以实现负载平衡-在单个LAN网段上支持多个逻辑IP子网。
A simple model of Master election among a set of redundant routers is to treat each router with equal preference and claim victory after converging to any router as Master. However, there are likely to be many environments where there is a distinct preference (or range of preferences) among the set of redundant routers. For example, this preference may be based upon access link cost or speed, router performance or reliability, or other policy considerations. The protocol should allow the expression of this relative path preference in an intuitive manner, and guarantee Master convergence to the most preferential router currently available.
在一组冗余路由器中，主选择的一个简单模型是以相同的偏好对待每个路由器，并在收敛到任何一个路由器作为主路由器后声称胜利。然而，在许多环境中，冗余路由器组之间可能存在明显的偏好（或偏好范围）。例如，此偏好可基于接入链路成本或速度、路由器性能或可靠性或其他策略考虑。该协议应允许以直观的方式表达这种相对路径偏好，并保证主机收敛到当前可用的最优先路由器。
Once Master election has been performed then any unnecessary transitions between Master and Backup routers can result in a disruption in service. The protocol should ensure after Master election that no state transition is triggered by any Backup router of equal or lower preference as long as the Master continues to function properly.
一旦执行了主选择，则主路由器和备份路由器之间任何不必要的转换都可能导致服务中断。协议应确保在主设备选择后，只要主设备继续正常工作，具有相同或更低优先级的任何备份路由器都不会触发状态转换。
Some environments may find it beneficial to avoid the state transition triggered when a router becomes available that is more preferential than the current Master. It may be useful to support an override of the immediate convergence to the preferred path.
某些环境可能会发现，避免在路由器可用时触发状态转换是有益的，因为该路由器比当前主机更优先。支持覆盖立即收敛到首选路径可能很有用。
The virtual router functionality is applicable to a wide range of internetworking environments that may employ different security policies. The protocol should require minimal configuration and overhead in the insecure operation, provide for strong authentication when increased security is required, and allow integration of new security mechanisms without breaking backwards compatible operation.
虚拟路由器功能适用于可能采用不同安全策略的各种互联网环境。该协议应在不安全操作中要求最小的配置和开销，在需要提高安全性时提供强身份验证，并允许在不破坏向后兼容操作的情况下集成新的安全机制。
Sending IP packets on a multiaccess LAN requires mapping from an IP address to a MAC address. The use of the virtual router MAC address in an extended LAN employing learning bridges can have a significant effect on the bandwidth overhead of packets sent to the virtual router. If the virtual router MAC address is never used as the source address in a link level frame then the station location is never learned, resulting in flooding of all packets sent to the virtual router. To improve the efficiency in this environment the protocol should: 1) use the virtual router MAC as the source in a packet sent by the Master to trigger station learning; 2) trigger a message immediately after transitioning to Master to update the station learning; and 3) trigger periodic messages from the Master to maintain the station learning cache.
在多址LAN上发送IP数据包需要从IP地址映射到MAC地址。在采用学习网桥的扩展LAN中使用虚拟路由器MAC地址会对发送到虚拟路由器的数据包的带宽开销产生显著影响。如果虚拟路由器MAC地址从未用作链路级帧中的源地址，则永远不会读入站点位置，从而导致发送到虚拟路由器的所有数据包泛滥。为了提高这种环境下的效率，该协议应该：1）使用虚拟路由器MAC作为主机发送的数据包中的源来触发站点学习；2） 转换到Master后立即触发消息以更新站点学习；以及3）触发来自主机的周期性消息，以维护站点学习缓存。
VRRP specifies an election protocol to provide the virtual router function described earlier. All protocol messaging is performed using IP multicast datagrams, thus the protocol can operate over a variety of multiaccess LAN technologies supporting IP multicast. Each VRRP virtual router has a single well-known MAC address allocated to it. This document currently only details the mapping to networks using the IEEE 802 48-bit MAC address. The virtual router MAC address is used as the source in all periodic VRRP messages sent by the Master router to enable bridge learning in an extended LAN.
VRRP指定一个选择协议，以提供前面描述的虚拟路由器功能。所有协议消息都使用IP多播数据报执行，因此该协议可以在支持IP多播的多种多址LAN技术上运行。每个VRRP虚拟路由器都有一个已知的MAC地址分配给它。本文档目前仅详细说明了使用IEEE 802 48位MAC地址到网络的映射。虚拟路由器MAC地址用作主路由器发送的所有定期VRRP消息的源，以在扩展LAN中启用网桥学习。
A virtual router is defined by its virtual router identifier (VRID) and a set of IP addresses. A VRRP router may associate a virtual router with its real addresses on an interface, and may also be configured with additional virtual router mappings and priority for virtual routers it is willing to backup. The mapping between VRID and addresses must be coordinated among all VRRP routers on a LAN.
虚拟路由器由其虚拟路由器标识符（VRID）和一组IP地址定义。VRRP路由器可以将虚拟路由器与其接口上的真实地址相关联，并且还可以为其愿意备份的虚拟路由器配置额外的虚拟路由器映射和优先级。必须在局域网上的所有VRRP路由器之间协调VRID和地址之间的映射。
However, there is no restriction against reusing a VRID with a different address mapping on different LANs. The scope of each virtual router is restricted to a single LAN.
但是，在不同的LAN上使用具有不同地址映射的VRID没有限制。每个虚拟路由器的作用域仅限于单个LAN。
To minimize network traffic, only the Master for each virtual router sends periodic VRRP Advertisement messages. A Backup router will not attempt to pre-empt the Master unless it has higher priority. This eliminates service disruption unless a more preferred path becomes available. It's also possible to administratively prohibit all pre-emption attempts. The only exception is that a VRRP router will always become Master of any virtual router associated with addresses it owns. If the Master becomes unavailable then the highest priority Backup will transition to Master after a short delay, providing a controlled transition of the virtual router responsibility with minimal service interruption.
为了最小化网络流量，只有每个虚拟路由器的主路由器定期发送VRRP广告消息。备份路由器不会尝试抢占主路由器，除非它具有更高的优先级。这将消除服务中断，除非有更首选的路径可用。也可以通过行政手段禁止所有先发制人的尝试。唯一的例外是，VRRP路由器将始终成为与其拥有的地址相关联的任何虚拟路由器的主机。如果主机变得不可用，则最高优先级的备份将在短时间延迟后过渡到主机，以最小的服务中断提供虚拟路由器责任的受控过渡。
VRRP defines three types of authentication providing simple deployment in insecure environments, added protection against misconfiguration, and strong sender authentication in security conscious environments. Analysis of the protection provided and vulnerability of each mechanism is deferred to Section 10.0 Security Considerations. In addition new authentication types and data can be defined in the future without affecting the format of the fixed portion of the protocol packet, thus preserving backward compatible operation.
VRRP定义了三种身份验证类型，在不安全的环境中提供简单的部署，增加了对错误配置的保护，以及在安全意识强的环境中提供强大的发送方身份验证。对提供的保护和每个机制的漏洞的分析将推迟到第10.0节安全注意事项。此外，将来可以定义新的身份验证类型和数据，而不会影响协议包固定部分的格式，从而保持向后兼容操作。
The VRRP protocol design provides rapid transition from Backup to Master to minimize service interruption, and incorporates optimizations that reduce protocol complexity while guaranteeing controlled Master transition for typical operational scenarios. The optimizations result in an election protocol with minimal runtime state requirements, minimal active protocol states, and a single message type and sender. The typical operational scenarios are defined to be two redundant routers and/or distinct path preferences among each router. A side effect when these assumptions are violated (i.e., more than two redundant paths all with equal preference) is that duplicate packets may be forwarded for a brief period during Master election. However, the typical scenario assumptions are likely to cover the vast majority of deployments, loss of the Master router is infrequent, and the expected duration in Master election convergence is quite small ( << 1 second ). Thus the VRRP optimizations represent significant simplifications in the protocol design while incurring an insignificant probability of brief network degradation.
VRRP协议设计提供了从备份到主服务器的快速转换，以最大限度地减少服务中断，并采用了一些优化，这些优化可降低协议复杂性，同时保证在典型操作场景下进行受控主服务器转换。优化的结果是选举协议具有最低的运行时状态要求、最低的活动协议状态以及单一的消息类型和发送方。典型的操作场景定义为两个冗余路由器和/或每个路由器之间的不同路径偏好。违反这些假设（即，两条以上的冗余路径具有相同的优先权）时的副作用是，在主选择期间，重复数据包可能会被转发一段短时间。然而，典型的场景假设可能涵盖绝大多数部署，主路由器的丢失很少，并且主选择收敛的预期持续时间非常小（<<1秒）。因此，VRRP优化代表了协议设计的显著简化，同时导致短暂网络退化的可能性很小。
The following figure shows a simple network with two VRRP routers implementing one virtual router. Note that this example is provided to help understand the protocol, but is not expected to occur in actual practice.
下图显示了一个简单的网络，其中两个VRRP路由器实现一个虚拟路由器。请注意，提供此示例是为了帮助理解协议，但实际操作中预计不会出现此示例。
+-----+ +-----+
| MR1 | | BR1 |
| | | |
| | | |
VRID=1 +-----+ +-----+
IP A ---------->* *<--------- IP B
| |
| |
| |
------------------+------------+-----+--------+--------+--------+--
^ ^ ^ ^
| | | |
(IP A) (IP A) (IP A) (IP A)
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| H1 | | H2 | | H3 | | H4 |
+-----+ +-----+ +--+--+ +--+--+
+-----+ +-----+
| MR1 | | BR1 |
| | | |
| | | |
VRID=1 +-----+ +-----+
IP A ---------->* *<--------- IP B
| |
| |
| |
------------------+------------+-----+--------+--------+--------+--
^ ^ ^ ^
| | | |
(IP A) (IP A) (IP A) (IP A)
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| H1 | | H2 | | H3 | | H4 |
+-----+ +-----+ +--+--+ +--+--+
Legend:
---+---+---+-- = Ethernet, Token Ring, or FDDI
H = Host computer
MR = Master Router
BR = Backup Router
* = IP Address
(IP) = default router for hosts
Legend:
---+---+---+-- = Ethernet, Token Ring, or FDDI
H = Host computer
MR = Master Router
BR = Backup Router
* = IP Address
(IP) = default router for hosts
The above configuration shows a very simple VRRP scenario. In this configuration, the end-hosts install a default route to the IP address of virtual router #1 (IP A) and both routers run VRRP. The router on the left becomes the Master for virtual router #1 (VRID=1) and the router on the right is the Backup for virtual router #1. If the router on the left should fail, the other router will take over virtual router #1 and its IP addresses, and provide uninterrupted service for the hosts.
上述配置显示了一个非常简单的VRRP场景。在此配置中，终端主机安装到虚拟路由器#1（IP a）的IP地址的默认路由，并且两个路由器都运行VRRP。左边的路由器成为虚拟路由器#1（VRID=1）的主路由器，右边的路由器是虚拟路由器#1的备份。如果左边的路由器出现故障，另一个路由器将接管虚拟路由器#1及其IP地址，并为主机提供不间断服务。
Note that in this example, IP B is not backed up by the router on the left. IP B is only used by the router on the right as its interface address. In order to backup IP B, a second virtual router would have to be configured. This is shown in the next section.
请注意，在此示例中，左侧的路由器不备份IP B。IP B仅由右侧的路由器用作其接口地址。为了备份IP B，必须配置第二个虚拟路由器。这将在下一节中显示。
The following figure shows a configuration with two virtual routers with the hosts spitting their traffic between them. This example is expected to be very common in actual practice.
下图显示了两个虚拟路由器的配置，其中主机在它们之间吐出流量。这个例子在实际操作中很常见。
+-----+ +-----+
| MR1 | | MR2 |
| & | | & |
| BR2 | | BR1 |
VRID=1 +-----+ +-----+ VRID=2
IP A ---------->* *<---------- IP B
| |
| |
| |
------------------+------------+-----+--------+--------+--------+--
^ ^ ^ ^
| | | |
(IP A) (IP A) (IP B) (IP B)
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| H1 | | H2 | | H3 | | H4 |
+-----+ +-----+ +--+--+ +--+--+
+-----+ +-----+
| MR1 | | MR2 |
| & | | & |
| BR2 | | BR1 |
VRID=1 +-----+ +-----+ VRID=2
IP A ---------->* *<---------- IP B
| |
| |
| |
------------------+------------+-----+--------+--------+--------+--
^ ^ ^ ^
| | | |
(IP A) (IP A) (IP B) (IP B)
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| H1 | | H2 | | H3 | | H4 |
+-----+ +-----+ +--+--+ +--+--+
Legend:
---+---+---+-- = Ethernet, Token Ring, or FDDI
H = Host computer
MR = Master Router
BR = Backup Router
* = IP Address
(IP) = default router for hosts
Legend:
---+---+---+-- = Ethernet, Token Ring, or FDDI
H = Host computer
MR = Master Router
BR = Backup Router
* = IP Address
(IP) = default router for hosts
In the above configuration, half of the hosts install a default route to virtual router #1's IP address (IP A), and the other half of the hosts install a default route to virtual router #2's IP address (IP B). This has the effect of load balancing the outgoing traffic, while also providing full redundancy.
在上述配置中，一半主机安装到虚拟路由器1的IP地址（IP a）的默认路由，另一半主机安装到虚拟路由器2的IP地址（IP B）的默认路由。这具有负载平衡输出流量的效果，同时还提供完全冗余。
The purpose of the VRRP packet is to communicate to all VRRP routers the priority and the state of the Master router associated with the Virtual Router ID.
VRRP包的目的是向所有VRRP路由器传送与虚拟路由器ID相关联的主路由器的优先级和状态。
VRRP packets are sent encapsulated in IP packets. They are sent to the IPv4 multicast address assigned to VRRP.
VRRP数据包被封装在IP数据包中发送。它们被发送到分配给VRRP的IPv4多播地址。
This section defines the format of the VRRP packet and the relevant fields in the IP header.
本节定义了VRRP数据包的格式以及IP报头中的相关字段。
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Type | Virtual Rtr ID| Priority | Count IP Addrs|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Adver Int | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
| . |
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (n) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Authentication Data (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Authentication Data (2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version| Type | Virtual Rtr ID| Priority | Count IP Addrs|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Adver Int | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
| . |
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP Address (n) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Authentication Data (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Authentication Data (2) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The primary IP address of the interface the packet is being sent from.
发送数据包的接口的主IP地址。
The IP multicast address as assigned by the IANA for VRRP is:
IANA为VRRP分配的IP多播地址为：
224.0.0.18
224.0.0.18
This is a link local scope multicast address. Routers MUST NOT forward a datagram with this destination address regardless of its TTL.
这是一个链路本地作用域多播地址。路由器不得转发具有此目标地址的数据报，无论其TTL如何。
The TTL MUST be set to 255. A VRRP router receiving a packet with the TTL not equal to 255 MUST discard the packet.
TTL必须设置为255。接收TTL不等于255的数据包的VRRP路由器必须丢弃该数据包。
The IP protocol number assigned by the IANA for VRRP is 112 (decimal).
IANA为VRRP分配的IP协议号为112（十进制）。
The version field specifies the VRRP protocol version of this packet. This document defines version 2.
版本字段指定此数据包的VRRP协议版本。本文档定义了版本2。
The type field specifies the type of this VRRP packet. The only packet type defined in this version of the protocol is:
类型字段指定此VRRP数据包的类型。本协议版本中定义的唯一数据包类型为：
1 ADVERTISEMENT
1广告
A packet with unknown type MUST be discarded.
必须丢弃类型未知的数据包。
The Virtual Router Identifier (VRID) field identifies the virtual router this packet is reporting status for.
虚拟路由器标识符（VRID）字段标识此数据包报告状态的虚拟路由器。
The priority field specifies the sending VRRP router's priority for the virtual router. Higher values equal higher priority. This field is an 8 bit unsigned integer field.
优先级字段为虚拟路由器指定发送VRRP路由器的优先级。值越高，优先级越高。此字段是一个8位无符号整数字段。
The priority value for the VRRP router that owns the IP address(es) associated with the virtual router MUST be 255 (decimal).
拥有与虚拟路由器关联的IP地址的VRRP路由器的优先级值必须为255（十进制）。
VRRP routers backing up a virtual router MUST use priority values between 1-254 (decimal). The default priority value for VRRP routers backing up a virtual router is 100 (decimal).
备份虚拟路由器的VRRP路由器必须使用1-254（十进制）之间的优先级值。备份虚拟路由器的VRRP路由器的默认优先级值为100（十进制）。
The priority value zero (0) has special meaning indicating that the current Master has stopped participating in VRRP. This is used to trigger Backup routers to quickly transition to Master without having to wait for the current Master to timeout.
优先级值0（0）具有特殊意义，表示当前主机已停止参与VRRP。这用于触发备份路由器快速过渡到主路由器，而无需等待当前主路由器超时。
The number of IP addresses contained in this VRRP advertisement.
此VRRP公告中包含的IP地址数。
The authentication type field identifies the authentication method being utilized. Authentication type is unique on a per interface basis. The authentication type field is an 8 bit unsigned integer. A packet with unknown authentication type or that does not match the locally configured authentication method MUST be discarded.
“身份验证类型”字段标识正在使用的身份验证方法。每个接口的身份验证类型都是唯一的。身份验证类型字段是8位无符号整数。必须丢弃身份验证类型未知或与本地配置的身份验证方法不匹配的数据包。
The authentication methods currently defined are:
当前定义的身份验证方法有：
0 - No Authentication 1 - Simple Text Password 2 - IP Authentication Header
0-无身份验证1-简单文本密码2-IP身份验证标头
The use of this authentication type means that VRRP protocol exchanges are not authenticated. The contents of the Authentication Data field should be set to zero on transmission and ignored on reception.
使用此身份验证类型意味着VRRP协议交换未经身份验证。认证数据字段的内容在传输时应设置为零，在接收时应忽略。
The use of this authentication type means that VRRP protocol exchanges are authenticated by a clear text password. The contents of the Authentication Data field should be set to the locally configured password on transmission. There is no default password. The receiver MUST check that the Authentication Data in the packet matches its configured authentication string. Packets that do not match MUST be discarded.
使用这种身份验证类型意味着VRRP协议交换通过明文密码进行身份验证。身份验证数据字段的内容应设置为传输时本地配置的密码。没有默认密码。接收方必须检查数据包中的身份验证数据是否与其配置的身份验证字符串匹配。必须丢弃不匹配的数据包。
Note that there are security implications to using Simple Text password authentication, and one should see the Security Consideration section of this document.
请注意，使用简单文本密码身份验证存在安全隐患，您应该参阅本文档的安全考虑部分。
The use of this authentication type means the VRRP protocol exchanges are authenticated using the mechanisms defined by the IP Authentication Header [AUTH] using "The Use of HMAC-MD5-96 within ESP and AH" [HMAC]. Keys may be either configured manually or via a key distribution protocol.
使用此身份验证类型意味着使用IP身份验证头[AUTH]定义的机制，使用“ESP和AH中HMAC-MD5-96的使用”[HMAC]对VRRP协议交换进行身份验证。密钥可以手动配置，也可以通过密钥分发协议配置。
If a packet is received that does not pass the authentication check due to a missing authentication header or incorrect message digest, then the packet MUST be discarded. The contents of the Authentication Data field should be set to zero on transmission and ignored on reception.
如果接收到的数据包由于缺少身份验证标头或不正确的消息摘要而未通过身份验证检查，则必须丢弃该数据包。认证数据字段的内容在传输时应设置为零，在接收时应忽略。
The Advertisement interval indicates the time interval (in seconds) between ADVERTISEMENTS. The default is 1 second. This field is used for troubleshooting misconfigured routers.
播发间隔表示播发之间的时间间隔（以秒为单位）。默认值为1秒。此字段用于对配置错误的路由器进行故障排除。
The checksum field is used to detect data corruption in the VRRP message.
校验和字段用于检测VRRP消息中的数据损坏。
The checksum is the 16-bit one's complement of the one's complement sum of the entire VRRP message starting with the version field. For computing the checksum, the checksum field is set to zero.
校验和是从版本字段开始的整个VRRP消息的补码和的16位补码。为了计算校验和，校验和字段设置为零。
One or more IP addresses that are associated with the virtual router. The number of addresses included is specified in the "Count IP Addrs" field. These fields are used for troubleshooting misconfigured routers.
与虚拟路由器关联的一个或多个IP地址。包含的地址数在“计数IP地址”字段中指定。这些字段用于对配置错误的路由器进行故障排除。
The authentication string is currently only utilized for simple text authentication, similar to the simple text authentication found in the Open Shortest Path First routing protocol [OSPF]. It is up to 8 characters of plain text. If the configured authentication string is shorter than 8 bytes, the remaining space MUST be zero-filled. Any VRRP packet received with an authentication string that does not match the locally configured authentication string MUST be discarded. The authentication string is unique on a per interface basis.
身份验证字符串目前仅用于简单文本身份验证，类似于开放最短路径优先路由协议[OSPF]中的简单文本身份验证。它最多为8个字符的纯文本。如果配置的身份验证字符串小于8字节，则剩余空间必须为零。必须丢弃接收到的任何带有与本地配置的身份验证字符串不匹配的身份验证字符串的VRRP数据包。每个接口的身份验证字符串都是唯一的。
There is no default value for this field.
此字段没有默认值。
Authentication_Type Type of authentication being used. Values are defined in section 5.3.6.
身份验证\正在使用的身份验证类型。数值在第5.3.6节中定义。
Authentication_Data Authentication data specific to the Authentication_Type being used.
身份验证数据特定于所使用的身份验证类型的身份验证数据。
VRID Virtual Router Identifier. Configured item in the range 1-255 (decimal). There is no default.
虚拟路由器标识符。配置的项目范围为1-255（十进制）。没有默认设置。
Priority Priority value to be used by this VRRP router in Master election for this virtual router. The value of 255 (decimal) is reserved for the router that owns the IP addresses associated with the virtual router. The value of 0 (zero) is reserved for Master router to indicate it is releasing responsibility for the virtual router. The range 1-254 (decimal) is available for VRRP routers backing up the virtual router. The default value is 100 (decimal).
此VRRP路由器在此虚拟路由器的主选择中使用的优先级值。255（十进制）的值是为拥有与虚拟路由器关联的IP地址的路由器保留的。0（零）的值保留给主路由器，以表示它正在释放对虚拟路由器的责任。范围1-254（十进制）可用于备份虚拟路由器的VRRP路由器。默认值为100（十进制）。
IP_Addresses One or more IP addresses associated with this virtual router. Configured item. No default.
IP_地址与此虚拟路由器关联的一个或多个IP地址。已配置项。没有默认值。
Advertisement_Interval Time interval between ADVERTISEMENTS (seconds). Default is 1 second.
广告间隔广告之间的时间间隔（秒）。默认值为1秒。
Skew_Time Time to skew Master_Down_Interval in seconds. Calculated as:
倾斜时间以秒为单位倾斜主间隔的时间。计算如下：
( (256 - Priority) / 256 )
（（256-优先级）/256）
Master_Down_Interval Time interval for Backup to declare Master down (seconds). Calculated as:
主控停机时间间隔备份宣布主控停机的时间间隔（秒）。计算如下：
(3 * Advertisement_Interval) + Skew_time
（3*广告间隔）+倾斜时间
Preempt_Mode Controls whether a higher priority Backup router preempts a lower priority Master. Values are True to allow preemption and False to not prohibit preemption. Default is True.
抢占模式控制高优先级备份路由器是否抢占低优先级主机。值为True表示允许抢占，值为False表示不禁止抢占。默认值为True。
Note: Exception is that the router that owns the IP address(es) associated with the virtual router always pre-empts independent of the setting of this flag.
注意：例外情况是，拥有与虚拟路由器关联的IP地址的路由器总是独立于此标志的设置进行抢占。
Master_Down_Timer Timer that fires when ADVERTISEMENT has not been heard for Master_Down_Interval.
Master_Down_定时器，当尚未听到Master_Down_间隔的广告时触发。
Adver_Timer Timer that fires to trigger sending of ADVERTISEMENT based on Advertisement_Interval.
Adver_定时器，根据广告间隔触发广告发送。
+---------------+
+--------->| |<-------------+
| | Initialize | |
| +------| |----------+ |
| | +---------------+ | |
| | | |
| V V |
+---------------+ +---------------+
| |---------------------->| |
| Master | | Backup |
| |<----------------------| |
+---------------+ +---------------+
+---------------+
+--------->| |<-------------+
| | Initialize | |
| +------| |----------+ |
| | +---------------+ | |
| | | |
| V V |
+---------------+ +---------------+
| |---------------------->| |
| Master | | Backup |
| |<----------------------| |
+---------------+ +---------------+
In the state descriptions below, the state names are identified by {state-name}, and the packets are identified by all upper case characters.
在下面的状态描述中，状态名称由{state name}标识，数据包由所有大写字符标识。
A VRRP router implements an instance of the state machine for each virtual router election it is participating in.
VRRP路由器为其参与的每个虚拟路由器选择实现一个状态机实例。
The purpose of this state is to wait for a Startup event. If a Startup event is received, then:
此状态的目的是等待启动事件。如果收到启动事件，则：
- If the Priority = 255 (i.e., the router owns the IP address(es) associated with the virtual router)
- 如果优先级=255（即，路由器拥有与虚拟路由器关联的IP地址）
o Send an ADVERTISEMENT o Broadcast a gratuitous ARP request containing the virtual router MAC address for each IP address associated with the virtual router. o Set the Adver_Timer to Advertisement_Interval o Transition to the {Master} state
o 发送广告以广播免费的ARP请求，其中包含与虚拟路由器关联的每个IP地址的虚拟路由器MAC地址。o将Adver_计时器设置为advision_Interval o转换为{Master}状态
else
其他的
o Set the Master_Down_Timer to Master_Down_Interval o Transition to the {Backup} state
o 将Master_Down_计时器设置为Master_Down_Interval o转换为{Backup}状态
endif
恩迪夫
The purpose of the {Backup} state is to monitor the availability and state of the Master Router.
{Backup}状态的目的是监视主路由器的可用性和状态。
While in this state, a VRRP router MUST do the following:
在此状态下，VRRP路由器必须执行以下操作：
- MUST NOT respond to ARP requests for the IP address(s) associated with the virtual router.
- 不得响应与虚拟路由器关联的IP地址的ARP请求。
- MUST discard packets with a destination link layer MAC address equal to the virtual router MAC address.
- 必须丢弃目标链路层MAC地址等于虚拟路由器MAC地址的数据包。
- MUST NOT accept packets addressed to the IP address(es) associated with the virtual router.
- 不得接受地址为与虚拟路由器关联的IP地址的数据包。
- If a Shutdown event is received, then:
- 如果收到关机事件，则：
o Cancel the Master_Down_Timer o Transition to the {Initialize} state
o 取消主计时器到{Initialize}状态的转换
endif
恩迪夫
- If the Master_Down_Timer fires, then:
- 如果主定时器触发，则：
o Send an ADVERTISEMENT o Broadcast a gratuitous ARP request containing the virtual router MAC address for each IP address associated with the virtual router o Set the Adver_Timer to Advertisement_Interval o Transition to the {Master} state
o 发送广告或广播免费的ARP请求，其中包含与虚拟路由器关联的每个IP地址的虚拟路由器MAC地址，或将Adver_计时器设置为广告间隔，或转换为{Master}状态
endif
恩迪夫
- If an ADVERTISEMENT is received, then:
- 如果收到广告，则：
If the Priority in the ADVERTISEMENT is Zero, then:
如果广告中的优先级为零，则：
o Set the Master_Down_Timer to Skew_Time
o 将主定时器设置为倾斜时间
else:
其他：
If Preempt_Mode is False, or If the Priority in the ADVERTISEMENT is greater than or equal to the local Priority, then:
如果Preempt_模式为False，或者如果播发中的优先级大于或等于本地优先级，则：
o Reset the Master_Down_Timer to Master_Down_Interval
o 将Master_Down_定时器重置为Master_Down_间隔
else:
其他：
o Discard the ADVERTISEMENT
o 丢弃广告
endif endif endif
endif endif endif
While in the {Master} state the router functions as the forwarding router for the IP address(es) associated with the virtual router.
在{Master}状态下，路由器充当与虚拟路由器关联的IP地址的转发路由器。
While in this state, a VRRP router MUST do the following:
在此状态下，VRRP路由器必须执行以下操作：
- MUST respond to ARP requests for the IP address(es) associated with the virtual router.
- 必须响应与虚拟路由器关联的IP地址的ARP请求。
- MUST forward packets with a destination link layer MAC address equal to the virtual router MAC address.
- 必须转发目标链路层MAC地址等于虚拟路由器MAC地址的数据包。
- MUST NOT accept packets addressed to the IP address(es) associated with the virtual router if it is not the IP address owner.
- 如果虚拟路由器不是IP地址所有者，则不得接受地址为与虚拟路由器关联的IP地址的数据包。
- MUST accept packets addressed to the IP address(es) associated with the virtual router if it is the IP address owner.
- 如果虚拟路由器是IP地址所有者，则必须接受地址为与虚拟路由器关联的IP地址的数据包。
- If a Shutdown event is received, then:
- 如果收到关机事件，则：
o Cancel the Adver_Timer o Send an ADVERTISEMENT with Priority = 0 o Transition to the {Initialize} state
o 取消Adver_计时器以发送优先级为0的播发，然后转换到{Initialize}状态
endif
恩迪夫
- If the Adver_Timer fires, then:
- 如果Adver_定时器触发，则：
o Send an ADVERTISEMENT o Reset the Adver_Timer to Advertisement_Interval
o 发送广告以将广告计时器重置为广告间隔
endif
恩迪夫
- If an ADVERTISEMENT is received, then:
- 如果收到广告，则：
If the Priority in the ADVERTISEMENT is Zero, then:
如果广告中的优先级为零，则：
o Send an ADVERTISEMENT o Reset the Adver_Timer to Advertisement_Interval
o 发送广告以将广告计时器重置为广告间隔
else:
其他：
If the Priority in the ADVERTISEMENT is greater than the local Priority, or If the Priority in the ADVERTISEMENT is equal to the local Priority and the primary IP Address of the sender is greater than the local primary IP Address, then:
如果播发中的优先级大于本地优先级，或者如果播发中的优先级等于本地优先级且发送方的主IP地址大于本地主IP地址，则：
o Cancel Adver_Timer o Set Master_Down_Timer to Master_Down_Interval o Transition to the {Backup} state
o 取消Adver_定时器o将Master_Down_定时器设置为Master_Down_时间间隔o转换为{Backup}状态
else:
其他：
o Discard ADVERTISEMENT
o 丢弃广告
endif endif endif
endif endif endif
Performed the following functions when a VRRP packet is received:
当接收到VRRP数据包时，执行以下功能：
- MUST verify that the IP TTL is 255. - MUST verify the VRRP version - MUST verify that the received packet length is greater than or equal to the VRRP header - MUST verify the VRRP checksum - MUST perform authentication specified by Auth Type
- 必须验证IP TTL是否为255。-必须验证VRRP版本-必须验证收到的数据包长度大于或等于VRRP报头-必须验证VRRP校验和-必须执行Auth Type指定的身份验证
If any one of the above checks fails, the receiver MUST discard the packet, SHOULD log the event and MAY indicate via network management that an error occurred.
如果上述任何一项检查失败，接收方必须丢弃数据包，记录事件，并通过网络管理表明发生了错误。
- MUST verify that the VRID is valid on the receiving interface
- 必须验证接收接口上的VRID是否有效
If the above check fails, the receiver MUST discard the packet.
如果上述检查失败，接收方必须丢弃数据包。
- MAY verify that the IP address(es) associated with the VRID are valid
- 可以验证与VRID关联的IP地址是否有效
If the above check fails, the receiver SHOULD log the event and MAY indicate via network management that a misconfiguration was detected. If the packet was not generated by the address owner (Priority does not equal 255 (decimal)), the receiver MUST drop the packet, otherwise continue processing.
如果上述检查失败，接收器应记录事件，并可通过网络管理指示检测到错误配置。如果数据包不是由地址所有者生成的（优先级不等于255（十进制）），则接收方必须丢弃数据包，否则继续处理。
- MUST verify that the Adver Interval in the packet is the same as the locally configured for this virtual router
- 必须验证数据包中的Adver间隔是否与为此虚拟路由器本地配置的相同
If the above check fails, the receiver MUST discard the packet, SHOULD log the event and MAY indicate via network management that a misconfiguration was detected.
如果上述检查失败，接收方必须丢弃数据包，记录事件，并通过网络管理表明检测到错误配置。
The following operations MUST be performed when transmitting a VRRP packet.
传输VRRP数据包时，必须执行以下操作。
- Fill in the VRRP packet fields with the appropriate virtual router configuration state - Compute the VRRP checksum - Set the source MAC address to Virtual Router MAC Address - Set the source IP address to interface primary IP address - Set the IP protocol to VRRP - Send the VRRP packet to the VRRP IP multicast group
- 用适当的虚拟路由器配置状态填写VRRP数据包字段-计算VRRP校验和-将源MAC地址设置为虚拟路由器MAC地址-将源IP地址设置为接口主IP地址-将IP协议设置为VRRP-将VRRP数据包发送到VRRP IP多播组
Note: VRRP packets are transmitted with the virtual router MAC address as the source MAC address to ensure that learning bridges correctly determine the LAN segment the virtual router is attached to.
注意：VRRP数据包以虚拟路由器MAC地址作为源MAC地址进行传输，以确保学习网桥正确确定虚拟路由器连接到的LAN网段。
The virtual router MAC address associated with a virtual router is an IEEE 802 MAC Address in the following format:
与虚拟路由器关联的虚拟路由器MAC地址是以下格式的IEEE 802 MAC地址：
00-00-5E-00-01-{VRID} (in hex in internet standard bit-order)
00-00-5E-00-01-{VRID}（以十六进制表示，按互联网标准位顺序）
The first three octets are derived from the IANA's OUI. The next two octets (00-01) indicate the address block assigned to the VRRP protocol. {VRID} is the VRRP Virtual Router Identifier. This mapping provides for up to 255 VRRP routers on a network.
前三个八位组来自IANA的OUI。接下来的两个八位字节（00-01）表示分配给VRRP协议的地址块。{VRID}是VRRP虚拟路由器标识符。此映射在网络上提供多达255个VRRP路由器。
ICMP Redirects may be used normally when VRRP is running between a group of routers. This allows VRRP to be used in environments where the topology is not symmetric.
当VRRP在一组路由器之间运行时，通常可以使用ICMP重定向。这允许VRRP在拓扑结构不对称的环境中使用。
The IP source address of an ICMP redirect should be the address the end host used when making its next hop routing decision. If a VRRP router is acting as Master for virtual router(s) containing addresses it does not own, then it must determine which virtual router the packet was sent to when selecting the redirect source address. One method to deduce the virtual router used is to examine the destination MAC address in the packet that triggered the redirect.
ICMP重定向的IP源地址应该是终端主机在做出下一跳路由决策时使用的地址。如果VRRP路由器充当包含其不拥有的地址的虚拟路由器的主路由器，则它必须在选择重定向源地址时确定数据包发送到哪个虚拟路由器。推断使用的虚拟路由器的一种方法是检查触发重定向的数据包中的目标MAC地址。
It may be useful to disable Redirects for specific cases where VRRP is being used to load share traffic between a number of routers in a symmetric topology.
在VRRP用于在对称拓扑中的多个路由器之间加载共享流量的特定情况下，禁用重定向可能很有用。
When a host sends an ARP request for one of the virtual router IP addresses, the Master virtual router MUST respond to the ARP request with the virtual MAC address for the virtual router. The Master virtual router MUST NOT respond with its physical MAC address. This allows the client to always use the same MAC address regardless of the current Master router.
当主机为其中一个虚拟路由器IP地址发送ARP请求时，主虚拟路由器必须使用虚拟路由器的虚拟MAC地址响应ARP请求。主虚拟路由器不得使用其物理MAC地址进行响应。这允许客户端始终使用相同的MAC地址，而不考虑当前的主路由器。
When a VRRP router restarts or boots, it SHOULD not send any ARP messages with its physical MAC address for the IP address it owns, it should only send ARP messages that include Virtual MAC addresses. This may entail:
当VRRP路由器重新启动或引导时，它不应该发送任何带有物理MAC地址的ARP消息，对于它拥有的IP地址，它应该只发送包含虚拟MAC地址的ARP消息。这可能需要：
- When configuring an interface, VRRP routers should broadcast a gratuitous ARP request containing the virtual router MAC address for each IP address on that interface.
- 配置接口时，VRRP路由器应广播一个免费的ARP请求，其中包含该接口上每个IP地址的虚拟路由器MAC地址。
- At system boot, when initializing interfaces for VRRP operation; delay gratuitous ARP requests and ARP responses until both the IP address and the virtual router MAC address are configured.
- 系统启动时，初始化VRRP操作接口时；延迟免费的ARP请求和ARP响应，直到配置了IP地址和虚拟路由器MAC地址。
If Proxy ARP is to be used on a VRRP router, then the VRRP router must advertise the Virtual Router MAC address in the Proxy ARP message. Doing otherwise could cause hosts to learn the real MAC address of the VRRP router.
如果要在VRRP路由器上使用代理ARP，则VRRP路由器必须在代理ARP消息中公布虚拟路由器MAC地址。否则会导致主机了解VRRP路由器的真实MAC地址。
FDDI interfaces remove from the FDDI ring frames that have a source MAC address matching the device's hardware address. Under some conditions, such as router isolations, ring failures, protocol transitions, etc., VRRP may cause there to be more than one Master router. If a Master router installs the virtual router MAC address as the hardware address on a FDDI device, then other Masters' ADVERTISEMENTS will be removed from the ring during the Master convergence, and convergence will fail.
FDDI接口从具有与设备硬件地址匹配的源MAC地址的FDDI环帧中移除。在某些情况下，例如路由器隔离、环故障、协议转换等，VRRP可能会导致存在多个主路由器。如果主路由器将虚拟路由器MAC地址安装为FDDI设备上的硬件地址，则在主汇聚期间，其他主路由器的播发将从环中删除，并且汇聚将失败。
To avoid this an implementation SHOULD configure the virtual router MAC address by adding a unicast MAC filter in the FDDI device, rather than changing its hardware MAC address. This will prevent a Master router from removing any ADVERTISEMENTS it did not originate.
为了避免这种情况，实现应该通过在FDDI设备中添加单播MAC过滤器来配置虚拟路由器MAC地址，而不是更改其硬件MAC地址。这将阻止主路由器删除其未发起的任何播发。
Token ring has several characteristics which make running VRRP difficult. These include:
令牌环的几个特点使运行VRRP变得困难。这些措施包括：
- In order to switch to a new master located on a different bridge token ring segment from the previous master when using source route bridges, a mechanism is required to update cached source route information.
- 在使用源路由网桥时，为了切换到位于与前一个主机不同的网桥令牌环段上的新主机，需要一种机制来更新缓存的源路由信息。
- No general multicast mechanism supported across old and new token ring adapter implementations. While many newer token ring adapters support group addresses, token ring functional address support is the only generally available multicast mechanism. Due to the limited number of token ring functional addresses these may collide with other usage of the same token ring functional addresses.
- 新旧令牌环适配器实现之间不支持通用多播机制。虽然许多较新的令牌环适配器支持组地址，但令牌环功能地址支持是唯一普遍可用的多播机制。由于令牌环功能地址的数量有限，这些地址可能会与相同令牌环功能地址的其他用途发生冲突。
Due to these difficulties, the preferred mode of operation over token ring will be to use a token ring functional address for the VRID virtual MAC address. Token ring functional addresses have the two high order bits in the first MAC address octet set to B'1'. They range from 03-00-00-00-00-80 to 03-00-02-00-00-00 (canonical format). However, unlike multicast addresses, there is only one unique functional address per bit position. The functional addresses addresses 03-00-00-10-00-00 through 03-00-02-00-00-00 are reserved by the Token Ring Architecture [TKARCH] for user-defined applications. However, since there are only 12 user-defined token ring functional addresses, there may be other non-IP protocols using the same functional address. Since the Novell IPX [IPX] protocol uses
由于这些困难，令牌环上的首选操作模式将是为VRID虚拟MAC地址使用令牌环功能地址。令牌环功能地址将第一个MAC地址八位字节中的两个高位设置为B'1'。它们的范围从03-00-00-00-00-80到03-00-02-00-00-00（标准格式）。但是，与多播地址不同，每个位位置只有一个唯一的功能地址。功能地址03-00-00-10-00-00到03-00-02-00-00-00由令牌环体系结构[TKARCH]为用户定义的应用程序保留。然而，由于只有12个用户定义的令牌环功能地址，因此可能存在使用相同功能地址的其他非IP协议。因为Novell IPX[IPX]协议使用
the 03-00-00-10-00-00 functional address, operation of VRRP over token ring will avoid use of this functional address. In general, token ring VRRP users will be responsible for resolution of other user-defined token ring functional address conflicts.
03-00-00-10-00-00功能地址，通过令牌环操作VRRP将避免使用此功能地址。通常，令牌环VRRP用户将负责解决其他用户定义的令牌环功能地址冲突。
VRIDs are mapped directly to token ring functional addresses. In order to decrease the likelihood of functional address conflicts, allocation will begin with the largest functional address. Most non-IP protocols use the first or first couple user-defined functional addresses and it is expected that VRRP users will choose VRIDs sequentially starting with 1.
VRID直接映射到令牌环功能地址。为了减少功能地址冲突的可能性，分配将从最大的功能地址开始。大多数非IP协议使用第一个或第一对用户定义的功能地址，预计VRRP用户将从1开始依次选择VRID。
VRID Token Ring Functional Address
---- -----------------------------
1 03-00-02-00-00-00
2 03-00-04-00-00-00
3 03-00-08-00-00-00
4 03-00-10-00-00-00
5 03-00-20-00-00-00
6 03-00-40-00-00-00
7 03-00-80-00-00-00
8 03-00-00-01-00-00
9 03-00-00-02-00-00
10 03-00-00-04-00-00
11 03-00-00-08-00-00
VRID Token Ring Functional Address
---- -----------------------------
1 03-00-02-00-00-00
2 03-00-04-00-00-00
3 03-00-08-00-00-00
4 03-00-10-00-00-00
5 03-00-20-00-00-00
6 03-00-40-00-00-00
7 03-00-80-00-00-00
8 03-00-00-01-00-00
9 03-00-00-02-00-00
10 03-00-00-04-00-00
11 03-00-00-08-00-00
Or more succinctly, octets 3 and 4 of the functional address are equal to (0x4000 >> (VRID - 1)) in non-canonical format.
或者更简洁地说，功能地址的八位字节3和4在非规范格式中等于（0x4000>>（VRID-1））。
Since a functional address cannot be used used as a MAC level source address, the real MAC address is used as the MAC source address in VRRP advertisements. This is not a problem for bridges since packets addressed to functional addresses will be sent on the spanning-tree explorer path [802.1D].
由于功能地址不能用作MAC级源地址，因此实际MAC地址在VRRP广告中用作MAC源地址。这对于网桥来说不是问题，因为发往功能地址的数据包将在生成树资源管理器路径[802.1D]上发送。
The functional address mode of operation MUST be implemented by routers supporting VRRP on token ring.
功能地址操作模式必须由在令牌环上支持VRRP的路由器实现。
Additionally, routers MAY support unicast mode of operation to take advantage of newer token ring adapter implementations which support non-promiscuous reception for multiple unicast MAC addresses and to avoid both the multicast traffic and usage conflicts associated with the use of token ring functional addresses. Unicast mode uses the same mapping of VRIDs to virtual MAC addresses as Ethernet. However, one important difference exists. ARP request/reply packets contain the virtual MAC address as the source MAC address. The reason for this is that some token ring driver implementations keep a cache of MAC address/source routing information independent of the ARP cache.
此外，路由器可支持单播操作模式，以利用支持多个单播MAC地址的非混杂接收的较新令牌环适配器实现，并避免与令牌环功能地址的使用相关联的多播通信量和使用冲突。单播模式使用与以太网相同的VRID到虚拟MAC地址的映射。然而，存在一个重要的区别。ARP请求/应答数据包包含虚拟MAC地址作为源MAC地址。原因是，一些令牌环驱动程序实现将MAC地址/源路由信息的缓存与ARP缓存保持独立。
Hence, these implementations need have to receive a packet with the virtual MAC address as the source address in order to transmit to that MAC address in a source-route bridged network.
因此，这些实现需要接收具有虚拟MAC地址作为源地址的分组，以便在源路由桥接网络中传输到该MAC地址。
Unicast mode on token ring has one limitation which should be considered. If there are VRID routers on different source-route bridge segments and there are host implementations which keep their source-route information in the ARP cache and do not listen to gratuitous ARPs, these hosts will not update their ARP source-route information correctly when a switch-over occurs. The only possible solution is to put all routers with the same VRID on the same source-bridge segment and use techniques to prevent that bridge segment from being a single point of failure. These techniques are beyond the scope this document.
令牌环上的单播模式有一个应考虑的限制。如果在不同的源路由网桥段上有VRID路由器，并且有主机实现将其源路由信息保留在ARP缓存中，并且不侦听免费的ARP，则在发生切换时，这些主机将无法正确更新其ARP源路由信息。唯一可能的解决方案是将具有相同VRID的所有路由器放在同一源网桥段上，并使用技术防止网桥段成为单一故障点。这些技术超出了本文档的范围。
For both the multicast and unicast mode of operation, VRRP advertisements sent to 224.0.0.18 should be encapsulated as described in [RFC1469].
对于多播和单播操作模式，发送至224.0.0.18的VRRP广告应按照[RFC1469]中所述进行封装。
VRRP is designed for a range of internetworking environments that may employ different security policies. The protocol includes several authentication methods ranging from no authentication, simple clear text passwords, and strong authentication using IP Authentication with MD5 HMAC. The details on each approach including possible attacks and recommended environments follows.
VRRP是为一系列可能采用不同安全策略的互联网环境而设计的。该协议包括多种身份验证方法，包括无身份验证、简单明文密码和使用MD5 HMAC的IP身份验证的强身份验证。下面将详细介绍每种方法，包括可能的攻击和推荐的环境。
Independent of any authentication type VRRP includes a mechanism (setting TTL=255, checking on receipt) that protects against VRRP packets being injected from another remote network. This limits most vulnerabilities to local attacks.
独立于任何身份验证类型，VRRP包括一种机制（设置TTL=255，接收时检查），可防止从另一远程网络注入VRRP数据包。这限制了大多数易受本地攻击的漏洞。
The use of this authentication type means that VRRP protocol exchanges are not authenticated. This type of authentication SHOULD only be used in environments were there is minimal security risk and little chance for configuration errors (e.g., two VRRP routers on a LAN).
使用此身份验证类型意味着VRRP协议交换未经身份验证。只有在安全风险最小且配置错误的可能性很小的环境中（例如，局域网上的两个VRRP路由器），才应使用这种类型的身份验证。
The use of this authentication type means that VRRP protocol exchanges are authenticated by a simple clear text password.
使用这种身份验证类型意味着VRRP协议交换通过简单的明文密码进行身份验证。
This type of authentication is useful to protect against accidental misconfiguration of routers on a LAN. It protects against routers inadvertently backing up another router. A new router must first be configured with the correct password before it can run VRRP with another router. This type of authentication does not protect against hostile attacks where the password can be learned by a node snooping VRRP packets on the LAN. The Simple Text Authentication combined with the TTL check makes it difficult for a VRRP packet to be sent from another LAN to disrupt VRRP operation.
这种类型的身份验证有助于防止局域网上路由器的意外错误配置。它可以防止路由器无意中备份另一个路由器。新路由器必须首先配置正确的密码，然后才能使用其他路由器运行VRRP。这种类型的身份验证无法防止恶意攻击，因为节点可以通过窥探局域网上的VRRP数据包来获取密码。简单的文本身份验证与TTL检查相结合，使得从另一个LAN发送VRRP数据包很难中断VRRP操作。
This type of authentication is RECOMMENDED when there is minimal risk of nodes on a LAN actively disrupting VRRP operation. If this type of authentication is used the user should be aware that this clear text password is sent frequently, and therefore should not be the same as any security significant password.
当LAN上的节点主动中断VRRP操作的风险最小时，建议使用这种类型的身份验证。如果使用这种类型的身份验证，用户应该知道此明文密码经常发送，因此不应与任何重要安全密码相同。
The use of this authentication type means the VRRP protocol exchanges are authenticated using the mechanisms defined by the IP Authentication Header [AUTH] using "The Use of HMAC-MD5-96 within ESP and AH", [HMAC]. This provides strong protection against configuration errors, replay attacks, and packet corruption/modification.
使用此身份验证类型意味着使用IP身份验证头[AUTH]定义的机制，使用“ESP和AH中HMAC-MD5-96的使用”[HMAC]对VRRP协议交换进行身份验证。这为配置错误、重播攻击和数据包损坏/修改提供了强大的保护。
This type of authentication is RECOMMENDED when there is limited control over the administration of nodes on a LAN. While this type of authentication does protect the operation of VRRP, there are other types of attacks that may be employed on shared media links (e.g., generation of bogus ARP replies) which are independent from VRRP and are not protected.
当对LAN上节点的管理控制有限时，建议使用这种类型的身份验证。虽然这种类型的身份验证确实可以保护VRRP的操作，但在共享媒体链接上可能会使用其他类型的攻击（例如，生成虚假ARP回复），这些攻击独立于VRRP，不受保护。
The authors would like to thank Glen Zorn, and Michael Lane, Clark Bremer, Hal Peterson, Tony Li, Barbara Denny, Joel Halpern, Steve Bellovin, and Thomas Narten for their comments and suggestions.
作者要感谢格伦·佐恩、迈克尔·莱恩、克拉克·布雷默、哈尔·彼得森、托尼·李、芭芭拉·丹尼、乔尔·哈尔伯恩、史蒂夫·贝洛文和托马斯·纳滕的评论和建议。
[802.1D] International Standard ISO/IEC 10038: 1993, ANSI/IEEE Std 802.1D, 1993 edition.
[802.1D]国际标准ISO/IEC 10038:1993，ANSI/IEEE标准802.1D，1993年版。
[AUTH] Kent, S., and R. Atkinson, "IP Authentication Header", Work in Progress.
[AUTH]Kent，S.和R.Atkinson，“IP身份验证头”，工作正在进行中。
[DISC] Deering, S., "ICMP Router Discovery Messages", RFC 1256, September 1991.
[DISC]Deering，S.，“ICMP路由器发现消息”，RFC 12561991年9月。
[DHCP] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997.
[DHCP]Droms，R.，“动态主机配置协议”，RFC 21311997年3月。
[HMAC] Madson, C., and R. Glenn, "The Use of HMAC-MD5-96 within ESP and AH", Work in Progress.
[HMAC]Madson，C.和R.Glenn，“HMAC-MD5-96在ESP和AH中的使用”，正在进行中。
[HSRP] Li, T., Cole, B., Morton, P., and D. Li, "Cisco Hot Standby Router Protocol (HSRP)", RFC 2281, March 1998.
[HSRP]Li，T.，Cole，B.，Morton，P.，和D.Li，“思科热备用路由器协议（HSRP）”，RFC 22811998年3月。
[IPSTB] Higginson, P., M. Shand, "Development of Router Clusters to Provide Fast Failover in IP Networks", Digital Technical Journal, Volume 9 Number 3, Winter 1997.
[IPSTB]Higginson，P.，M.Shand，“在IP网络中开发路由器集群以提供快速故障切换”，《数字技术期刊》，第9卷第3期，1997年冬季。
[IPX] Novell Incorporated., "IPX Router Specification", Version 1.10, October 1992.
[IPX]Novell Incorporated.，“IPX路由器规范”，版本1.10，1992年10月。
[OSPF] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[OSPF]Moy，J.，“OSPF版本2”，STD 54，RFC 23281998年4月。
[RIP] Hedrick, C., "Routing Information Protocol", RFC 1058, June 1988.
[RIP]Hedrick，C.，“路由信息协议”，RFC 1058，1988年6月。
[RFC1469] Pusateri, T., "IP over Token Ring LANs", RFC 1469, June 1993.
[RFC1469]Pusateri，T.，“令牌环局域网上的IP”，RFC 14691993年6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。
[TKARCH] IBM Token-Ring Network, Architecture Reference, Publication SC30-3374-02, Third Edition, (September, 1989).
[TKARCH]IBM令牌环网，体系结构参考，出版物SC30-3374-02，第三版（1989年9月）。
Steven Knight Phone: +1 612 943-8990 Ascend Communications EMail: Steven.Knight@ascend.com High Performance Network Division 10250 Valley View Road, Suite 113 Eden Prairie, MN USA 55344 USA
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Douglas Weaver Phone: +1 612 943-8990 Ascend Communications EMail: Doug.Weaver@ascend.com High Performance Network Division 10250 Valley View Road, Suite 113 Eden Prairie, MN USA 55344 USA
道格拉斯·韦弗电话：+1 612 943-8990 Ascend通讯电子邮件：道格。Weaver@ascend.com美国明尼苏达州伊甸园大草原113室谷景路10250号高性能网络分部美国明尼苏达州55344
David Whipple Phone: +1 206 703-3876 Microsoft Corporation EMail: dwhipple@microsoft.com One Microsoft Way Redmond, WA USA 98052-6399 USA
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Robert Hinden Phone: +1 408 990-2004 Nokia EMail: hinden@iprg.nokia.com 232 Java Drive Sunnyvale, CA 94089 USA
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P. Higginson Phone: +44 118 920 6293 Digital Equipment Corp. EMail: higginson@mail.dec.com Digital Park Imperial Way Reading Berkshire RG2 0TE UK
P.Higginson电话：+44 118 920 6293数字设备公司电子邮件：higginson@mail.dec.com数字公园帝国路阅读伯克希尔RG2 0TE英国
M. Shand Phone: +44 118 920 4424 Digital Equipment Corp. EMail: shand@mail.dec.com Digital Park Imperial Way Reading Berkshire RG2 0TE UK
M.Shand电话：+44 118 920 4424数字设备公司电子邮件：shand@mail.dec.com数字公园帝国路阅读伯克希尔RG2 0TE英国
Acee Lindem Phone: 1-919-254-1805 IBM Corporation E-Mail: acee@raleigh.ibm.com P.O. Box 12195 Research Triangle Park, NC 27709 USA
Acee Lindem电话：1-919-254-1805 IBM公司电子邮件：acee@raleigh.ibm.com美国北卡罗来纳州三角研究园12195号邮政信箱27709
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