by: Networking

Types:

  • STP Standard
  • PVST+ (Per-VLAN STP, by Cisco)
  • RSTP (Faster STP)
  • Rapid PVST+ (Per-VLAN RSTP, by Cisco)

Root Bridge Election:

  • BID = (Priority + VLAN) + MAC
    • Lowest Priority
    • Lowest VLAN
    • Lowest MAC

Commands:

spanning-tree mode pvst
spanning-tree mode rapid-pvst
spanning-tree mode mst
spanning-tree vlan 1 root primary  # VLAN number 1-4094
spanning-tree vlan 1 priority 0    # Priority 0-61440
                                   # Default: 32768
                                   # Increments of 4096
spanning-tree portfast             # Skip to forwarding mode
spanning-tree uplinkfast           # Accelerate new root port
no spanning-tree vlan 1            # VLAN number 1-4094

Verification Commands:

show spanning-tree
show spanning-tree vlan 1 root     # VLAN number 1-4094
show spanning-tree vlan 1 bridge   # VLAN number 1-4094