Cisco Mst 配置

测试设备Cisco 3750G12S,3560G-48TS各一台.

 

New37(config)#spanning-tree mode mst     //启用MST,默认为PVST+

New37(config)#spanning-tree mst configuration      //进入MST配置模式

New37(config-mst)#name test     // 注意交换机之间的实例Name要相同,不然会出现各自说自己是根桥.

New37(config-mst)#instance 1 vlan 2,3

New37(config-mst)#instance 2 vlan 4,14   //配置实例包括的Vlan,关于Vlan,VTP,Trunk配置这里不提了.

New37(config-if-range)#spanning-tree mst 1 port-priority 96

New37(config-if-range)#spanning-tree mst 2 port-priority 160 //MST端口优先级,我们要让3750成为vlan 2,3的根桥,3560成vlan 4,14 的根桥,默认端口优先级为128,+/-16.

或者

New37(config)#spanning-tree mst 1 root primary

New37(config)#spanning-tree mst 2 root secondary

 

New35(config)#spanning-tree mst 2 root primary

New35(config)#spanning-tree mst 1 root secondary

 

结果如下:

New37#sh spanning-tree

MST0
  Spanning tree enabled protocol mstp
  Root ID    Priority    32768
             Address     0013.c342.f100
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768  (priority 32768 sys-id-ext 0)
             Address     0013.c342.f100
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi2/0/1             Desg FWD 20000     128.55   P2p
Gi2/0/2             Desg FWD 20000     128.56   P2p

         
MST1
  Spanning tree enabled protocol mstp
  Root ID    Priority    24577
             Address     0013.c342.f100
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    24577  (priority 24576 sys-id-ext 1)
             Address     0013.c342.f100
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi2/0/1             Desg FWD 20000      96.55   P2p
Gi2/0/2             Desg FWD 20000      96.56   P2p

         
MST2
  Spanning tree enabled protocol mstp
  Root ID    Priority    24578
             Address     0024.f935.7a00
             Cost        20000
             Port        55 (GigabitEthernet2/0/1)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    28674  (priority 28672 sys-id-ext 2)
             Address     0013.c342.f100
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi2/0/1             Root FWD 20000     160.55   P2p
Gi2/0/2             Altn BLK 20000     160.56   P2p

 

默认3750优先级高,除已经配置的vlan外均以3750为根桥,MST2根桥为3560,测试完成.