27.8.2 Checking the status of single spanning tree

Use the show spanning-tree command to check information about Single Spanning Tree. The STP or Rapid STP operation mode can be checked in Mode. To check that the topology has been built properly, make sure that the contents of Root Bridge ID are correct, along with Status and Role in Port Information.

Figure 27-10: Single spanning tree information
> show spanning-tree single Date 20XX/09/04 11:42:06 UTC Single Spanning Tree:Enabled Mode:Rapid STP Bridge ID Priority:32768 MAC Address:0012.e205.0900 Bridge Status:Designated Root Bridge ID Priority:32768 MAC Address:0012.e205.0900 Root Cost:0 Root Port:- Port Information 1/0/1 Up Status:Forwarding Role:Root 1/0/2 Up Status:Forwarding Role:Designated 1/0/3 Up Status:Blocking Role:Alternate 1/0/4 Down Status:Disabled Role:- 1/0/10 Up Status:Forwarding Role:Designated PortFast 1/0/11 Up Status:Forwarding Role:Designated PortFast 1/0/12 Up Status:Forwarding Role:Designated PortFast >

Figure 27-10: Single spanning tree information

> show spanning-tree single
Date 20XX/09/04 11:42:06 UTC
Single Spanning Tree:Enabled  Mode:Rapid STP
  Bridge ID        Priority:32768       MAC Address:0012.e205.0900
    Bridge Status:Designated
  Root Bridge ID   Priority:32768       MAC Address:0012.e205.0900
    Root Cost:0
    Root Port:-
  Port Information
    1/0/1      Up    Status:Forwarding  Role:Root                 
    1/0/2      Up    Status:Forwarding  Role:Designated           
    1/0/3      Up    Status:Blocking    Role:Alternate            
    1/0/4      Down  Status:Disabled    Role:-                    
    1/0/10     Up    Status:Forwarding  Role:Designated PortFast  
    1/0/11     Up    Status:Forwarding  Role:Designated PortFast  
    1/0/12     Up    Status:Forwarding  Role:Designated PortFast  
>