實驗拓撲：
實驗需求：
假設R3路由器爲外網路由器，上面有一條虛擬網段3.3.3.0，模擬外網。
C1爲vlan10 ,C2爲vlan 20。
R1作爲vlan10的主路由器，vlan20的備用路由器。R2作爲vlan10的備用路由器，vlan10的主路由器。
測試熱備路由的效果。
實驗步驟：
配置C1,C2的IP地址，配置交換機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 //開啓路由
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 //創建監聽端口
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 //虛擬網關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 //設置搶佔
R1(config-if)#vrrp 1 priority 100 //設置優先級,主要高於備用優先級
R1(config-if)#vrrp 1 track 1 //設置監聽端口
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 //要低於主路由器的優先級
*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.分別在R1，R2上檢查一下vrrp的配置是否正確
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
無誤，分別配置上行口IP
R1(config)#int f1/3
R1(config-if)#no switchport 將二層口變爲三層口
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
配置外網路由器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 //建立虛擬接口
*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.使用動態協議RIP互相告知網段
R3(config)#router rip //啓動RIP協議
R3(config-router)#network 3.3.3.0 //告知與自己直連網段，以便相鄰路由器學習
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.可以連通測試了
可以發現,C1走的路線是R1，C2走的路線是R2。這是剛纔配置的vrrp優先級決定的。
將R1的上行口f1/3 和 R3的f0/0口 shutdown,觀察tracert的變化
此時R1已經的不同，電腦C1的路線已經由R1切換到了R2。
再將R1的f1/3口和R3的f0/0口 no shutdown，觀察變化
可以發現R1又將C1的路線搶佔過來了。這樣，熱備路由的目的已經實現。
C2同理。