What is port Fast and BPDU guard?

The PortFast and BPDU. A BPDU is a data message transmitted across a local area network to detect loops in network topologies. Guard features enhance network reliability, manageability, and security for Layer-2 STP. STP is a network protocol that builds a logical loop-free topology for Ethernet networks. .

What is BPDU guard and BPDU filter?

The BPDU Guard feature prevents the port from receiving any BPDUs but does not prevent it from sending them. If any BPDUs are received, the port will be errdisabled. The BPDU Filter feature effectively disables STP on the selected ports by preventing them from sending or receiving any BPDUs.

What happens if a Portfast port receives a BPDU?

If an interface is enabled for portfast receives BPDU , the port is shut down immediately.

What is BPDU filtering?

BPDU filter is a feature used to filter sending or receiving BPDUs on a switchport. It is extremely useful on those ports which are configured as portfast ports as there is no need to send or receive any BPDU messages on of these ports. BPDU filter can be configured globally or under the interface level.

What is Cisco port fast?

Portfast on switch ports connected to a single workstation or server allows those devices to connect to the network immediately, instead of waiting for the port to transition from the listening and learning states to the forwarding state.

Does Portfast disable spanning tree?

A common misunderstanding among Cisco students is that portfast disables spanning-tree on a certain interface. This is not correct however…if you enable portfast on an interface then it will jump to the forwarding state of spanning-tree. We still run spanning-tree on the interface!

Should I enable BPDU guard?

You should globally enable BPDU filtering on a switch so that hosts connected to these ports do not receive BPDUs. If a BPDU is received on a Port Fast-enabled STP port, the interface loses its Port Fast-operational status, and BPDU filtering is disabled.

Does PortFast disable spanning tree?

How do I enable port fast?

In switch A, run the following commands as port 20 is connected to a host.

1. Enter the configuration mode for the interface.
2. Shut down the interface.
3. Change the portfast setting.
4. Review the portfast status.
5. Reset the default spanning tree portfast value for the interface.
6. Review the portfast status.

Why do we need Portfast?

The PortFast feature is introduced to avoid network connectivity issues. These issues are caused by delays in STP enabled ports moving from blocking-state to forwarding-state after transitioning from the listening and learning states.

Should I use Portfast?

PortFast feature should be used only to connect a single workstation to a switch port to avoid layer 2 switching loop. Spanning Tree PortFast feature causes a port to enter the forwarding state immediately, bypassing the listening and learning states.