实验拓扑：
实验需求：
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假设R3路由器为外网路由器，上面有一条虚拟网段3.3.3.0，模拟外网。
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C1为vlan10 ,C2为vlan 20。
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R1作为vlan10的主路由器，vlan20的备用路由器。R2作为vlan10的备用路由器，vlan10的主路由器。
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测试热备路由的效果。
实验步骤：
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配置C1,C2的IP地址，配置交换机R4
R4#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R4(config)#no ip routing
R4(config)#vlan 10,20
R4(config-vlan)#ex
R4(config)#int f1/1
R4(config-if)#switchport access vlan 10
R4(config-if)#int f1/2
R4(config-if)#switchport access vlan 20
R4(config-if)#int f1/3
R4(config-if)#int range f1/3 -4
R4(config-if-range)#switchport mode trunk
R4(config-if-range)#
*Mar 1 00:04:35.099: %DTP-5-TRUNKPORTON: Port Fa1/3-4 has become dot1q trunk
2.配置R1
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#ip routing //开启路由
R1(config)#int f1/4
R1(config-if)#no sh
R1(config-if)#switchport mode trunk
R1(config-if)#
*Mar 1 00:05:45.635: %DTP-5-TRUNKPORTON: Port Fa1/4 has become dot1q trunk
R1(config)#track 1 int f1/3 line-protocol
R1(config-track)#track 2 int f1/4 line-protocol //创建监听端口
R1(config)#vlan 10
R1(config-vlan)#vlan 20
R1(config-vlan)#ex
(1)配置vlan 10
R1(config)#int vlan 10
R1(config-if)#ip add 192.168.10.10 255.255.255.0
R1(config-if)#no sh
R1(config-if)#ex
*Mar 1 00:07:54.263: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan10, changed state to up
R1(config-vlan)#ex
R1(config)#int vlan 10
R1(config-if)#vrrp 1 ?
authentication Authentication
description Group specific description
ip Enable Virtual Router Redundancy Protocol (VRRP) for IP
preempt Enable preemption of lower priority Master
priority Priority of this VRRP group
shutdown Disable VRRP Configuration
timers Set the VRRP timers
track Event Tracking
R1(config-if)#vrrp 1 ip 192.168.10.1 //虚拟网关IP
*Mar 1 00:09:20.763: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Init -> Backup
*Mar 1 00:09:24.375: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Backup -> Master
R1(config-if)#vrrp 1 preempt //设置抢占
R1(config-if)#vrrp 1 priority 100 //设置优先级,主要高于备用优先级
R1(config-if)#vrrp 1 track 1 //设置监听端口
R1(config-if)#vrrp 1 track 2
(2)配置vlan 20
R1(config)#int vlan 20
*Mar 1 00:10:39.051: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan20, changed state to up
R1(config-if)#ip add 192.168.20.10 255.255.255.0
R1(config-if)#no sh
R1(config-if)#vrrp 2 ip 192.168.20.1
*Mar 1 00:11:02.399: %VRRP-6-STATECHANGE: Vl20 Grp 2 state Init -> Backup
R1(config-if)#vrrp 2 preempt
*Mar 1 00:11:06.007: %VRRP-6-STATECHANGE: Vl20 Grp 2 state Backup -> Master
R1(config-if)#vrrp 2 priority 95 //要低于主路由器的优先级
*Mar 1 00:12:58.911: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Master -> Backup
*Mar 1 00:13:09.515: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Backup -> Master
*Mar 1 00:13:47.295: %VRRP-6-STATECHANGE: Vl20 Grp 2 state Master -> Backup
3.配置R2
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#ip routing
R2(config)#int f1/4
R2(config-if)#no sh
R2(config-if)#switchport mode trunk
R2(config-if)#
*Mar 1 00:10:09.595: %DTP-5-TRUNKPORTON: Port Fa1/4 has become dot1q trunk
R2(config-if)#ex
R1(config)#track 1 int f1/3 line-protocol
R1(config-track)#track 2 int f1/4 line-protocol
R2(config)#vlan 10
R2(config-vlan)#vlan 20
(1)配置vlan 10
R2(config-vlan)#int vlan 10
*Mar 1 00:10:20.911: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan10, changed state to up
R2(config-if)#ip add 192.168.10.20 255.255.255.0
R2(config-if)#no sh
R2(config-if)#vrrp 1 ip 192.168.10.1
*Mar 1 00:12:54.007: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Init -> Backup
R2(config-if)#vrrp 1 preempt
*Mar 1 00:12:57.619: %VRRP-6-STATECHANGE: Vl10 Grp 1 state Backup -> Master
R2(config-if)#vrrp 1 priority 95
R2(config-if)#ex
R2(config)#
(2)配置vlan 20
R2(config)#int vlan 20
*Mar 1 00:13:14.543: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan20, changed state to up
R2(config-if)#ip add 192.168.20.20 255.255.255.0
R2(config-if)#no sh
R2(config-if)#vrrp 2 ip 192.168.20.1
*Mar 1 00:13:42.375: %VRRP-6-STATECHANGE: Vl20 Grp 2 state Init -> Backup
R2(config-if)#vrrp 2 preempt
*Mar 1 00:13:45.983: %VRRP-6-STATECHANGE: Vl20 Grp 2 state Backup -> Master
R2(config-if)#vrrp 2 priority 100
R2(config-if)#vrrp 2 track 1
R2(config-if)#vrrp 2 track 2
R2(config-if)#ex
4.分别在R1，R2上检查一下vrrp的配置是否正确
R1#show vrrp b
Interface Grp Pri Time Own Pre State Master addr Group addr
Vl10 1 100 3609 Y Master 192.168.10.10 192.168.10.1
Vl20 2 95 3628 Y Backup 192.168.20.20 192.168.20.1
R2#show vrrp b
Interface Grp Pri Time Own Pre State Master addr Group addr
Vl10 1 95 3628 Y Backup 192.168.10.10 192.168.10.1
Vl20 2 100 3609 Y Master 192.168.20.20 192.168.20.1
无误，分别配置上行口IP
R1(config)#int f1/3
R1(config-if)#no switchport 将二层口变为三层口
R1(config-if)#ip add 13.0.0.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#
*Mar 1 00:14:36.199: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/3, changed state to up
R1(config-if)#ex
R2(config)#int f1/3
R2(config-if)#no switchport
*Mar 1 00:14:50.827: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/3, changed state to up
R2(config-if)#ip add 23.0.0.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#ex
配置外网路由器R3
R3#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R3(config)#int f0/0
R3(config-if)#ip add 13.0.0.3 255.255.255.0
R3(config-if)#no sh
R3(config-if)#int f0/1
*Mar 1 00:15:18.651: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
*Mar 1 00:15:19.651: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
R3(config-if)#ip add 23.0.0.3 255.255.255.0
R3(config-if)#no sh
*Mar 1 00:15:32.571: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
*Mar 1 00:15:33.571: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
R3(config)#int l0 //建立虚拟接口
*Mar 1 00:15:36.259: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to up.
R3(config-if)#ip add 3.3.3.3 255.255.255.0
R3(config-if)#no sh
R3(config-if)#ex
5.使用动态协议RIP互相告知网段
R3(config)#router rip //启动RIP协议
R3(config-router)#network 3.3.3.0 //告知与自己直连网段，以便相邻路由器学习
R3(config-router)#network 13.0.0.0
R3(config-router)#network 23.0.0.0
R1(config)#router rip
R1(config-router)#network 13.0.0.0
R1(config-router)#network 192.168.10.0
R1(config-router)#network 192.168.20.0
R2(config)#router rip
R2(config-router)#network 23.0.0.0
R2(config-router)#network 192.168.10.0
R2(config-router)#network 192.168.20.0
6.可以连通测试了
可以发现,C1走的路线是R1，C2走的路线是R2。这是刚才配置的vrrp优先级决定的。
将R1的上行口f1/3 和 R3的f0/0口 shutdown,观察tracert的变化。
此时R1已经的不同，电脑C1的路线已经由R1切换到了R2。再将R1的f1/3口和R3的f0/0口 no shutdown，观察变化
可以发现R1又将C1的路线抢占过来了。这样，热备路由的目的已经实现。
C2同理。
