Spanning Tree Protocol

When a switch receives multiple Hellos with equal calculated cost, it uses the following tiebreakers:
1. Pick the lowest value of the forwarding switch's bridge ID.
2. Use the lowest port priority of the neighboring switch. The neighboring switch added its own port priority to the Hello before forwarding it.
3. Use the lowest internal port number (of the forwarding switch) as listed inside the received Hellos.


spanning-tree mode {mst | pvst | rapid-pvst}
[no] spanning-tree vlan vlan-id
spanning-tree vlan vlan-id {forwardtime seconds | hello-time seconds | max-age seconds | priority priority | {root {primary | secondary} [diameter net-diameter [hello-time seconds]]}}
spanning-tree vlan x cost y
spanning-tree vlan x port-priority y

channel-group channel-group-number mode {auto [non-silent] | desirable [non-silent] | on | active | passive}
channel-protocol {lacp | pagp}
interface port-channel port-channel-number

spanning-tree portfast
spanning-tree bpduguard {enable | disable}
spanning-tree uplinkfast
spanning-tree backbonefast
spanning-tree mst instance-id priority priority
spanning-tree mst configuration

show spanning-tree { root | brief | summary }
show spanning-tree { uplinkfast | backbonefast }
show interface
show interface trunk
show etherchannel [summary]
show interface switchport
show vtp status
show controllers