小议企业交换网络环境—被忽略STP优化(3)-e路由器网

SW3#show spanning-tree brief

VLAN1
Spanning tree enabled protocol ieee uplinkfast enabled
Root ID    Priority    8192
             Address     c007.00c0.0000
             Cost        3019
             Port        42 (FastEthernet1/1)
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority    49152
             Address     c009.00c0.0000
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300

Interface                                   Designated
Name                 Port ID Prio Cost Sts Cost Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/1      128.42   128 3019 FWD     0 8192 c007.00c0.0000 128.42
FastEthernet1/2      128.43   128 3019 BLK    19 16384 c008.00c0.0000 128.42
FastEthernet1/15     128.56   128 3019 FWD 3019 49152 c009.00c0.0000 128.56

VLAN10
Spanning tree enabled protocol ieee uplinkfast enabled
Root ID    Priority    8192
             Address     c007.00c0.0001
             Cost        3019
             Port        42 (FastEthernet1/1)
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority    49152
             Address     c009.00c0.0001
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300

Interface                                   Designated
Name                 Port ID Prio Cost Sts Cost Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/1      128.42   128 3019 FWD     0 8192 c007.00c0.0001 128.42
FastEthernet1/2      128.43   128 3019 BLK    19 16384 c008.00c0.0001 128.42

VLAN20
Spanning tree enabled protocol ieee uplinkfast enabled
Root ID    Priority    8192
             Address     c008.00c0.0002
             Cost        3019
             Port        43 (FastEthernet1/2)
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority    49152
             Address     c009.00c0.0002
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300

Interface                                   Designated
Name                 Port ID Prio Cost Sts Cost Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/1      128.42   128 3019 BLK    19 16384 c007.00c0.0002 128.42
FastEthernet1/2      128.43   128 3019 FWD     0 8192 c008.00c0.0002 128.42

结语

以上可以看出SW1是VLAN1\VLAN10的根交换机，VLAN20的备根交换机；

SW2是VLAN20的根交换机，VLAN1\VLAN10的备根交换机；

在vlan1和vlan10 中时是阻塞的端口，但是在vlan20中是处于转发状态；

在vlan20 中是阻塞的端口，但是在vlan1和vlan10 中是处于转发状态；

经过这样优化的stp拓扑，更有效的利用了交换机系统和带宽资源，同时也因为stp提供更短的收敛时间，可以更好地提供网络服务。

同时注意在接入层交换机下连接口启用portfast命令，一定要加上bpduguard，否则只使用portfast命令，如果下面接入一台非法交换机会造成暂时性生成树环路。

篇外语

现在有些企业boss能花在网络上的经费确实不多，却又希望能实现良好的效果，于是乎，后勤部与IT部协商后一般会花钱买较好的核心层/汇聚层交换机，对于接入层交换机一般选用H3C、TP-LINK、D-Link等傻瓜型交换机（一个字“省”），配置的结果是，你有时真的是无法掌控你的接入层网络现状…出处：http://ciscoren.blog.51cto.com/1066670/883。