VRRP基本概述
VRRP能够在不改变组网的情况下，将多台路由器虚拟成一个虚拟路由器，通过配置虚拟路由器的IP地址为默认网关，实现网关的备份。
协议版本：VRRPv2 和VRRPv3
VRRPv2仅适用于IPv4网络，VRRPv3适用于IPv4和IPv6网络
VRRP协议报文：只有一种报文 Advertisement报文，其目的IP地址是224.0.0.18，目的MAC地址是01-00-5e-00-00-12，协议号112。
VRRP基本结构
VRRP状态机
开启VRRP的设备有三种状态：
- Initialize：初始化状态，设备刚开机或宕机。
- Backup：备份状态，设备进行VRRP协商的状态
- Master：主状态，设备处于转发状态，是优先级最高的Backup设备。
VRRP配置实现
##SW3##
[SW3]vlan bat 10 20
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW3]int e0/0/1
[SW3-Ethernet0/0/1]p l a
[SW3-Ethernet0/0/1]p d v 10
[SW3-Ethernet0/0/1]un sh
Info: Interface Ethernet0/0/1 is not shutdown.
[SW3-Ethernet0/0/1]int e0/0/2
[SW3-Ethernet0/0/2]p l a
[SW3-Ethernet0/0/2]p d v 20
[SW3-Ethernet0/0/2]un sh
Info: Interface Ethernet0/0/2 is not shutdown.
[SW3-Ethernet0/0/2]int g0/0/1
[SW3-GigabitEthernet0/0/1]p l t
[SW3-GigabitEthernet0/0/1]p t a v 10 20
[SW3-GigabitEthernet0/0/1]un sh
Info: Interface GigabitEthernet0/0/1 is not shutdown.
[SW3-GigabitEthernet0/0/1]int g0/0/2
[SW3-GigabitEthernet0/0/2]p l t
[SW3-GigabitEthernet0/0/2]p t a v 10 20
[SW3-GigabitEthernet0/0/2]un sh
Info: Interface GigabitEthernet0/0/2 is not shutdown.
##SW1## [SW1]vlan bat 10 20 100 Info: This operation may take a few seconds. Please wait for a moment...done.
[SW1]int g0/0/1 [SW1-GigabitEthernet0/0/1]p l a [SW1-GigabitEthernet0/0/1]p d v 100 [SW1-GigabitEthernet0/0/1]un sh Info: Interface GigabitEthernet0/0/1 is not shutdown.
[SW1-GigabitEthernet0/0/1]int g0/0/2 [SW1-GigabitEthernet0/0/2]p l t [SW1-GigabitEthernet0/0/2]p t a v 10 20 [SW1-GigabitEthernet0/0/2]un sh Info: Interface GigabitEthernet0/0/2 is not shutdown.
[SW1-GigabitEthernet0/0/2]int vlanif10 [SW1-Vlanif10]ip add 192.168.10.10 24 [SW1-Vlanif10]vrrp vrid 1 virtual [SW1-Vlanif10]vrrp vrid 1 virtual-ip 192.168.10.1 [SW1-Vlanif10]vrrp vrid 1 priority 120 [SW1-Vlanif10]vrrp vrid 1 track interface g0/0/1 [SW1-Vlanif10]vrrp vrid 1 track interface g0/0/2
[SW1-Vlanif10]int vlanif20 [SW1-Vlanif20]ip add 192.168.20.10 24 [SW1-Vlanif20]vrrp vrid 2 virtual-ip 192.168.20.1 [SW1-Vlanif20]vrrp vrid 2 priority 115
[SW1-Vlanif20]int vlanif 100 [SW1-Vlanif100]ip add 11.0.0.2 30 [SW1-Vlanif100]q [SW1]ip route-static 0.0.0.0 0.0.0.0 11.0.0.1
##SW2## [SW2]vlan bat 10 20 100 Info: This operation may take a few seconds. Please wait for a moment...done. [SW2]int g0/0/1 [SW2-GigabitEthernet0/0/1]p l a [SW2-GigabitEthernet0/0/1]p d v 100 [SW2-GigabitEthernet0/0/1]un sh Info: Interface GigabitEthernet0/0/1 is not shutdown. [SW2-GigabitEthernet0/0/1]int g0/0/2 [SW2-GigabitEthernet0/0/2]p l t [SW2-GigabitEthernet0/0/2]p t a v 10 20 [SW2-GigabitEthernet0/0/2]un sh Info: Interface GigabitEthernet0/0/2 is not shutdown. [SW2-GigabitEthernet0/0/2]int vlanif 10 [SW2-Vlanif10]ip add 192.168.10.20 24 [SW2-Vlanif10]vrrp vrid 1 virtual-ip 192.168.10.1 [SW2-Vlanif10]vrrp vrid 1 priority 115 [SW2-Vlanif10]int vlanif20 [SW2-Vlanif20]ip add 192.168.20.20 24 [SW2-Vlanif20]vrrp vrid 2 virtual-ip 192.168.20.1 [SW2-Vlanif20]vrrp vrid 2 priority 120 [SW2-Vlanif20]vrrp vrid 2 track interface g0/0/1 [SW2-Vlanif20]vrrp vrid 2 track interface g0/0/2 [SW2-Vlanif20]int vlanif100 [SW2-Vlanif100]ip add 12.0.0.2 30 [SW2-Vlanif100]q [SW2]ip route-static 0.0.0.0 0.0.0.0 12.0.0.1
##R1## [R1]int g0/0/0 [R1-GigabitEthernet0/0/0]ip add 11.0.0.1 30 [R1-GigabitEthernet0/0/0]int g0/0/1 [R1-GigabitEthernet0/0/1]ip add 12.0.0.1 30 [R1-GigabitEthernet0/0/1]int loo 0 [R1-LoopBack0]ip add 1.1.1.1 24 [R1]ip route-static 192.168.10.0 24 11.0.0.2 [R1]ip route-static 192.168.10.0 24 12.0.0.2 pre 70 [R1]ip route-static 192.168.20.0 24 12.0.0.2 [R1]ip route-static 192.168.20.0 24 11.0.0.2 pre 70