写给大佬看的STP算法详细配置实验过程

选择出根网桥、根端口、指定端口、被阻塞的端口。
方案

步骤

1）每个广播域选择根网桥（Root Bridge）

每个非根网桥选择根端口（Root Ports）
每个网段上选择指定端口（Designated Ports）

结果如图：

配置STP
使用eNSP搭建实验环境：

步骤

实现此案例需要按照如下步骤进行。

[A]stp mode stp
[B]stp mode stp
[C]stp mode stp
[D]stp mode stp
[A]dis stp
-------[CIST Global Info][Mode STP]-------
CIST Bridge         :32768.4c1f-cc3b-03cb
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-cc17-3481 / 200000
CIST RegRoot/IRPC   :32768.4c1f-cc3b-03cb / 0
CIST RootPortId     :128.2
BPDU-Protection     :Disabled
TC or TCN received  :106
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:9m:8s
Number of TC        :12
Last TC occurred    :Ethernet0/0/2
[B]dis stp
-------[CIST Global Info][Mode STP]-------
CIST Bridge         :32768.4c1f-cc17-3481
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-cc17-3481 / 0
CIST RegRoot/IRPC   :32768.4c1f-cc17-3481 / 0
CIST RootPortId     :0.0
BPDU-Protection     :Disabled
TC or TCN received  :23
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:9m:52s
Number of TC        :13
Last TC occurred    :Ethernet0/0/4
[C]dis stp
-------[CIST Global Info][Mode STP]-------
CIST Bridge         :32768.4c1f-cc50-3d65
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-cc17-3481 / 400000
CIST RegRoot/IRPC   :32768.4c1f-cc50-3d65 / 0
CIST RootPortId     :128.4
BPDU-Protection     :Disabled
TC or TCN received  :92
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:10m:26s
Number of TC        :11
Last TC occurred    :Ethernet0/0/4
[D]dis stp
-------[CIST Global Info][Mode STP]-------
CIST Bridge         :32768.4c1f-cc22-4507
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-cc17-3481 / 200000
CIST RegRoot/IRPC   :32768.4c1f-cc22-4507 / 0
CIST RootPortId     :128.2
BPDU-Protection     :Disabled
TC or TCN received  :49
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:11m:12s
Number of TC        :13
Last TC occurred    :Ethernet0/0/2

可以看出，交换机B是根网桥。

[A]stp priority 4096
[A]dis stp
-------[CIST Global Info][Mode STP]-------
CIST Bridge         :4096 .4c1f-cc3b-03cb
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-cc3b-03cb / 0
CIST RegRoot/IRPC   :4096 .4c1f-cc3b-03cb / 0
CIST RootPortId     :0.0
BPDU-Protection     :Disabled
TC or TCN received  :108
TC count per hello  :0
STP Converge Mode   :Normal 
Time since last TC  :0 days 0h:0m:14s
Number of TC        :15
Last TC occurred    :Ethernet0/0/3

此时，根网桥已经是交换机A了。