Spanning Tree

Spanning Tree Protocol (STP) configuration prevents Layer 2 loops and provides redundant path management on NX-OS devices, supporting PVST+ (per-VLAN spanning tree) and MST (Multiple Spanning Tree) modes with bridge assurance and loop guard for enhanced network stability. Global settings control STP mode selection, pathcost method, FCoE integration, linecard ISSU behavior, and L2 gateway STP domain ID. Spanning tree interface-level configuration manages BPDU filter, BPDU guard, port cost, guard mode (root/loop), link type, port type (edge/network/normal), and port priority across Ethernet and port-channel interfaces.

Diagram

Classes

configuration (nxos.devices)

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

ethernets (nxos.devices.configuration.interfaces)

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

port_channels (nxos.devices.configuration.interfaces)

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

spanning_tree (nxos.devices.configuration)

Name	Type	Constraint	Mandatory
bridge_assurance	Boolean	`true`, `false`	No
fcoe	Boolean	`true`, `false`	No
l2_gateway_stp_domain_id	Integer	min: `0`, max: `200000000`	No
linecard_issu	Choice	`disruptive`, `non-disruptive`, `auto`	No
loopguard	Boolean	`true`, `false`	No
mode	Choice	`mst`, `pvrst`	No
pathcost_method	Choice	`auto`, `short`, `long`	No

spanning_tree (nxos.devices.configuration.interfaces.ethernets)

Name	Type	Constraint	Mandatory
bpdufilter	Boolean	`true`, `false`	No
bpduguard	Boolean	`true`, `false`	No
cost	Integer	min: `0`, max: `200000000`	No
guard	Choice	`root`, `loop`, `none`	No
link_type	Choice	`auto`, `p2p`, `shared`	No
port_type	Choice	`edge`, `network`, `normal`	No
port_priority	Integer	min: `0`, max: `224`	No

Examples

Example 1: PVST+ mode with bridge assurance and loopguard on a VXLAN leaf switch

nxos:
  devices:
    - name: LEAF1
      configuration:
        spanning_tree:
          mode: pvrst
          loopguard: true
          bridge_assurance: true

Example 2: MST mode with long pathcost and stateful HA on a spine switch

nxos:
  devices:
    - name: SPINE1
      configuration:
        spanning_tree:
          mode: mst
          bridge_assurance: true
          loopguard: true
          pathcost_method: long

Example 3: Spanning tree with FCoE support, linecard ISSU behavior, and L2 gateway domain ID

nxos:
  devices:
    - name: BORDER-LEAF1
      configuration:
        spanning_tree:
          mode: pvrst
          bridge_assurance: true
          loopguard: true
          fcoe: true
          linecard_issu: non-disruptive
          l2_gateway_stp_domain_id: 100

Example 4: Interface-level spanning tree with edge port and BPDU guard on access-facing Ethernet

nxos:
  devices:
    - name: LEAF1
      configuration:
        interfaces:
          ethernets:
            - id: 1/1
              spanning_tree:
                port_type: edge
                bpduguard: true
                guard: root
          port_channels:
            - id: 100
              spanning_tree:
                port_type: network
                guard: loop
                link_type: p2p