Dell Configuration Guide for the S4048–ON System 9.14.2.6

Examples of Verifying Spanning Tree Information

To disable STP globally for all Layer 2 interfaces, use the disable command from PROTOCOL SPANNING TREE mode.

To verify that STP is enabled, use the show config command from PROTOCOL SPANNING TREE mode.

DellEMC(conf)#protocol spanning-tree 0
DellEMC(config-span)#show config
!
protocol spanning-tree 0
  no disable
DellEMC#

To view the spanning tree configuration and the interfaces that are participating in STP, use the show spanning-tree 0 command from EXEC privilege mode. If a physical interface is part of a port channel, only the port channel is listed in the command output.

R2#show spanning-tree 0
  Executing IEEE compatible Spanning Tree Protocol
    Bridge Identifier has priority 32768, address 0001.e826.ddb7
    Configured hello time 2, max age 20, forward delay 15
    Current root has priority 32768, address 0001.e80d.2462
    Root Port is 289 (TenGigabitEthernet 2/1), cost of root path is 4
    Topology change flag not set, detected flag not set
    Number of topology changes 3 last change occurred 0:16:11 ago
         from TenGigabitEthernet 2/3
    Timers: hold 1, topology change 35
            hello 2, max age 20, forward delay 15
    Times: hello 0, topology change 0, notification 0, aging Normal

  Port 289 (TenGigabitEthernet 2/1) is Forwarding
    Port path cost 4, Port priority 8, Port Identifier 8.289
    Designated root has priority 32768, address 0001.e80d.2462
    Designated bridge has priority 32768, address 0001.e80d.2462
    Designated port id is 8.496, designated path cost 0
    Timers: message age 1, forward delay 0, hold 0
    Number of transitions to forwarding state 1
    BPDU: sent 21, received 486
    The port is not in the portfast mode

  Port 290 (TenGigabitEthernet 2/2) is Blocking
    Port path cost 4, Port priority 8, Port Identifier 8.290
--More--
    Timers: message age 1, forward delay 0, hold 0
    Number of transitions to forwarding state 1
    BPDU: sent 21, received 486
    The port is not in the portfast mode

To confirm that a port is participating in Spanning Tree, use the show spanning-tree 0 brief command from EXEC privilege mode.

DellEMC#show spanning-tree 0 brief
  Executing IEEE compatible Spanning Tree Protocol
    Root ID Priority 32768, Address 0001.e80d.2462
    We are the root of the spanning tree
    Root Bridge hello time 2, max age 20, forward delay 15
    Bridge ID Priority 32768, Address 0001.e80d.2462
    Configured hello time 2, max age 20, forward delay 15
Interface                          Designated
Name    PortID Prio Cost Sts Cost  Bridge ID             PortID
-------------- ------ ---- ---- --- ----- --------------------
Te 1/1  8.496  8     4 DIS   0     32768 0001.e80d.2462  8.496
Te 1/2  8.497  8     4 DIS   0     32768 0001.e80d.2462  8.497
Te 1/3  8.513  8     4 FWD   0     32768 0001.e80d.2462  8.513
Te 1/4  8.514  8     4 FWD   0     32768 0001.e80d.2462  8.514
DellEMC#