一、拓扑

网络拓扑

二、配置

#
sysname LSW3
#
vlan batch 10 20
#
stp instance 10 root primary
stp instance 20 root secondary
#
stp region-configuration
 region-name MST1
 revision-level 1
 instance 10 vlan 10
 instance 20 vlan 20
 active region-configuration
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
interface GigabitEthernet0/0/10
 port link-type trunk
 port trunk allow-pass vlan 2 to 4094
#
return

三、查看角色

<LSW3>dis stp region-configuration 
 Oper configuration
   Format selector    :0             
   Region name        :MST1             
   Revision level     :1

   Instance   VLANs Mapped
      0       1 to 9, 11 to 19, 21 to 4094
     10       10
     20       20

<LSW3>  dis stp
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge         :32768.4c1f-cc81-05d8
Config Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
Active Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC      :32768.4c1f-cc04-52d3 / 20000
CIST RegRoot/IRPC   :32768.4c1f-cc81-05d8 / 0
CIST RootPortId     :128.12
BPDU-Protection     :Disabled
TC or TCN received  :56
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:2m:47s
Number of TC        :28
Last TC occurred    :GigabitEthernet0/0/12



-------[MSTI 10 Global Info]-------
MSTI Bridge ID      :0.4c1f-cc81-05d8
MSTI RegRoot/IRPC   :0.4c1f-cc81-05d8 / 0
MSTI RootPortId     :0.0
MSTI Root Type      :Primary root
Master Bridge       :32768.4c1f-cc81-05d8
Cost to Master      :0
TC received         :6
TC count per hello  :0
Time since last TC  :0 days 0h:1m:2s
Number of TC        :9
Last TC occurred    :GigabitEthernet0/0/12

<LSW9>
<LSW9>dis  stp
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge         :32768.4c1f-cc04-52d3
Config Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
Active Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC      :32768.4c1f-cc04-52d3 / 0
CIST RegRoot/IRPC   :32768.4c1f-cc04-52d3 / 0
CIST RootPortId     :0.0
BPDU-Protection     :Disabled
TC or TCN received  :42
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:6m:19s
Number of TC        :34
Last TC occurred    :GigabitEthernet0/0/3

四、最终的CIST逻辑拓扑为

image.png

五、抓包

image.png