Spanning Tree

Spanning Tree Protocol (STP) is a Layer 2 loop prevention mechanism that ensures a loop-free topology in Ethernet networks by selectively blocking redundant paths while maintaining network connectivity and providing automatic failover capabilities. It supports multiple implementations including Per-VLAN Spanning Tree Plus (PVST+), Rapid Per-VLAN Spanning Tree Plus (RPVST+), and Multiple Spanning Tree (MST) protocol, each offering different approaches to VLAN-aware loop prevention and convergence optimization. Spanning Tree configuration includes features like PortFast for edge ports, BPDU Guard for security, root bridge selection, and path cost manipulation to optimize network topology and ensure rapid recovery from link failures while preventing broadcast storms and network instability.

Diagram

Classes

configuration (iosxe.devices)

Name	Type	Constraint	Mandatory	Default Value
spanning_tree	Class	`[spanning_tree]`	No

spanning_tree (iosxe.devices.configuration)

Name	Type	Constraint	Mandatory
mode	Choice	`mst`, `pvst`, `rapid-pvst`	No
loopguard_default	Boolean	`true`, `false`	No
portfast_default	Boolean	`true`, `false`	No
portfast_bpduguard_default	Boolean	`true`, `false`	No
extend_system_id	Boolean	`true`, `false`	No
mst_instances	List	`[mst_instances]`	No

mst_instances (iosxe.devices.configuration.spanning_tree)

Name	Type	Constraint	Mandatory	Default Value
id	Integer	min: `0`, max: `4094`	Yes
vlan_ids	List	Integer	No

Examples

iosxe:
  devices:
    - name: Device1
      configuration:
        spanning_tree:
          mode: rapid-pvst
          loopguard_default: true
          portfast_default: true
          portfast_bpduguard_default: true
          extend_system_id: true
    - name: Device2
      configuration:
        spanning_tree:
          mode: mst
          loopguard_default: true
          portfast_default: false
          portfast_bpduguard_default: true
          extend_system_id: true
          mst_instances:
            - id: 0
              vlan_ids: [1, 10, 20, 30]
            - id: 1
              vlan_ids: [100, 200, 300]
            - id: 2
              vlan_ids: [400, 500, 600]