1、链路追踪的概念：
当网络中存在着HSRP的备份路由器时，可以配置HSRP的上行链路追踪，当指定的追踪接口down掉时，马上减小该HSRP设备的优先级，使另一个备份设备能马上被激活成为ACTIVE状态，并接替down掉的设备继续引导路由数据，实现网络的畅通性
2、拓扑规划：
3、案例实施：
1）、各设备配置：
R1配置：
interface Loopback0 ipaddress 202.102.12.1 255.255.255.0 interface Serial1/0 ipaddress 172.16.0.1 255.255.255.252 serial restart-delay 0 clock rate 64000 ! interface Serial1/1 ipaddress 172.16.0.5 255.255.255.252 serial restart-delay 0 clock rate 64000
R2配置：
interface FastEthernet0/0.10 encapsulation dot1Q 10 ipaddress 192.168.10.1 255.255.255.0 ipnat inside ipvirtual-reassembly standby 10 ip 192.168.10.254 standby 10 priority 120 standby 10 preempt standby 10 track Serial1/0 30 ! interface FastEthernet0/0.20 encapsulation dot1Q 20 ipaddress 192.168.20.1 255.255.255.0 ipnat inside ipvirtual-reassembly standby 20 ip 192.168.20.254 standby 20 preempt interface Serial1/0 ipaddress 172.16.0.2 255.255.255.252 ipnat outside ipvirtual-reassembly serial restart-delay 0 ip route 0.0.0.0 0.0.0.0 Serial1/0 ip nat inside source list 100 interfaceSerial1/0 overload
R3配置：
interface FastEthernet0/0.10 encapsulation dot1Q 10 ipaddress 192.168.10.2 255.255.255.0 ipnat inside ipvirtual-reassembly standby 10 ip 192.168.10.254 standby10 preempt ! interface FastEthernet0/0.20 encapsulation dot1Q 20 ipaddress 192.168.20.2 255.255.255.0 ipnat inside ipvirtual-reassembly standby 20 ip 192.168.20.254 standby 20 priority 120 standby 20 preempt standby 20 track Serial1/1 30 interface Serial1/1 ipaddress 172.16.0.5 255.255.255.252 ipnat outside ipvirtual-reassembly serial restart-delay 0 ip route 0.0.0.0 0.0.0.0 Serial1/1 ip nat inside source list 100 interfaceSerial1/1 overload
Sw1配置：
interface FastEthernet0/0 switchport mode trunk ! interface FastEthernet0/1 switchport mode trunk ! interface FastEthernet0/2 switchport mode trunk ! interface FastEthernet0/3 switchport access vlan 10 ! interface FastEthernet0/4 switchport access vlan 20 vlan database vlan10 vlan20
Sw2配置：
interface FastEthernet0/0 switchport mode trunk ! interface FastEthernet0/1 switchport mode trunk ! interface FastEthernet0/2 switchport mode trunk ! interface FastEthernet0/3 switchport access vlan 10 ! interface FastEthernet0/4 switchport access vlan 20 vlan database vlan10 vlan20
PC1配置：
no ip routing interface FastEthernet0/0 ipaddress 192.168.10.100 255.255.255.0 noip route-cache duplex auto speed auto ip default-gateway 192.168.10.254
PC2配置：
no ip routing interface FastEthernet0/0 ipaddress 192.168.20.100 255.255.255.0 noip route-cache duplex auto speed auto ip default-gateway 192.168.20.254
PC3配置：
no ip routing interface FastEthernet0/0 ipaddress 192.168.10.200 255.255.255.0 noip route-cache duplexauto speed auto ip default-gateway 192.168.10.254
PC4配置：
no ip routing interface FastEthernet0/0 ipaddress 192.168.20.200 255.255.255.0 noip route-cache ip default-gateway 192.168.20.254
2）、配置完成后查看R2和R3的HSRP信息：
R2：
R3：
此时在PC2上跟踪一下到202.102.12.1的路由情况
在PC3上跟踪到202.102.12.1的路有情况
此时将R1的接口S1/0设置为shutdown模式，再查看HSRP信息：
R2：
R3：
此时再在PC1和PC2上跟踪到202.102.12.1的路由，发现R3自动接管原先的路由：
PC1：
PC3：
时间： 2024-08-22 20:47:18