How To Configure Optional Spanning-Tree Features - Cisco Catalyst 2960 series Configuration Manual

How to Configure Optional Spanning-Tree Features

• It can only be enabled or disabled globally.
• It applies to all operational network ports, including alternate and backup ports.
• Only Rapid PVST+ and MST spanning tree protocols support Bridge Assurance. PVST+ does not support
• For Bridge Assurance to work properly, it must be supported and configured on both ends of a
• To enable Bridge Assurance on a port, BPDU filtering and BPDU Guard must be disabled.
• You can enable Bridge Assurance in conjunction with Loop Guard.
• You can enable Bridge Assurance in conjunction with Root Guard. The latter is designed to provide a
Related Topics
Enabling Bridge Assurance, on page 318
How to Configure Optional Spanning-Tree Features
Enabling PortFast
An interface with the PortFast feature enabled is moved directly to the spanning-tree forwarding state without
waiting for the standard forward-time delay.
If you enable the voice VLAN feature, the PortFast feature is automatically enabled. When you disable voice
VLAN, the PortFast feature is not automatically disabled.
You can enable this feature if your switch is running PVST+, Rapid PVST+, or MSTP.
Use PortFast only when connecting a single end station to an access or trunk port. Enabling this feature
Caution
on an interface connected to a switch or hub could prevent spanning tree from detecting and disabling
loops in your network, which could cause broadcast storms and address-learning problems.
This procedure is optional.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface interface-id
4. spanning-tree portfast [trunk]
5. end
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Bridge Assurance.
point-to-point link. If the device on one side of the link has Bridge Assurance enabled and the device
on the other side does not, the connecting port is blocked and in a Bridge Assurance inconsistent state.
We recommend that you enable Bridge Assurance throughout your network.
way to enforce the root bridge placement in the network.