Cisco Systems N3KC3064TFAL3 Configuring STP Extensions, STP Extensions Configuration Guidelines

Configuring STP Extensions

Configuring STP Extensions

put into a root-inconsistent (blocked) state. After the port stops send superior BPDUs, the port is unblocked again. Through STP, the port moves to the forwarding state. Recovery is automatic.

Root Guard enabled on an interface applies this functionality to all VLANs to which that interface belongs.

You can use Root Guard to enforce the root bridge placement in the network. Root Guard ensures that the port on which Root Guard is enabled is the designated port. Normally, root bridge ports are all designated ports, unless two or more of the ports of the root bridge are connected. If the bridge receives superior BPDUs on a Root Guard-enabled port, the bridge moves this port to a root-inconsistent STP state. In this way, Root Guard enforces the position of the root bridge.

You cannot configure Root Guard globally.

Note You can enable Root Guard on all spanning tree port types: normal, edge, and network ports.

Configuring STP Extensions

STP Extensions Configuration Guidelines

When configuring STP extensions, follow these guidelines:

•Configure all access and trunk ports connected to hosts as edge ports.

•Bridge Assurance runs only on point-to-point spanning tree network ports. You must configure each side of the link for this feature.

•Loop Guard does not run on spanning tree edge ports.

•Enabling Loop Guard on ports that are not connected to a point-to-point link will not work.

•You cannot enable Loop Guard if Root Guard is enabled.

Configuring Spanning Tree Port Types Globally

The spanning tree port type designation depends on the type of device the port is connected to, as follows:

•Edge—Edge ports are connected to hosts and can be either an access port or a trunk port.

•Network—Network ports are connected only to switches or bridges.

•Normal—Normal ports are neither edge ports nor network ports; they are normal spanning tree ports. These ports can be connected to any type of device.

You can configure the port type either globally or per interface. By default, the spanning tree port type is normal.

Before You Begin

Ensure that STP is configured.

Ensure that you are configuring the ports correctly for the type of device to which the interface is connected.

Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)

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