8.11 根防护

1.查看SW1的实例1根为SW1

[sw1]display interface
Hardware address is 4c1f-ccfb-35ef
[sw1]display stp instance 1
-------[MSTI 1 Global Info]-------
MSTI Bridge ID      :4096.4c1f-ccfb-35ef
MSTI RegRoot/IRPC   :4096.4c1f-ccfb-35ef / 0
MSTI RootPortId     :0.0
Master Bridge       :4096.4c1f-ccfb-35ef
Cost to Master      :0
TC received         :0
TC count per hello  :0
Time since last TC  :0 days 0h:2m:53s
Number of TC        :4
Last TC occurred    :GigabitEthernet0/0/1

2.SW1的G0/0/1、G0/0/2端口启用根防护

[sw1]interface GigabitEthernet 0/0/1
[sw1-GigabitEthernet0/0/1]stp root-protection 
[sw1]interface GigabitEthernet 0/0/2
[sw1-GigabitEthernet0/0/2]stp root-protection  

3.修改SW3实例1优先级为0，查看SW1的STP信息

[SW3]stp instance 1 priority 0
[sw1]display stp      
CIST Bridge         :4096 .4c1f-ccfb-35ef
Config Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
Active Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC      :4096 .4c1f-ccfb-35ef / 0
CIST RegRoot/IRPC   :4096 .4c1f-ccfb-35ef / 0

4.关闭SW1的G0/0/2口根保护

[sw1]interface GigabitEthernet 0/0/2
[sw1-GigabitEthernet0/0/2]undo stp root-protection