What is Cisco BPDU guard?

BPDU guard is a portfast feature that protects your spanning tree on edge ports (Access ports). It (in layman’s terms) monitors your port for BPDUs. If it see’s one (presumably from an unauthorized switch, hub or host), it shuts the port down (err-disabled).

What is RSTP BPDU?

In RSTP, a non-root bridge actively sends RSTP BPDUs at the hello time through designated ports without waiting for the root bridge to send RSTP BPDUs. This enables RSTP to quickly detect link failures.

How do I enable BPDU guard on Cisco switch?

At the interface level, you can enable BPDU filtering on any STP port by using the spanning-tree bpdufilter enable interface configuration command without also enabling the Port Fast feature. This command prevents the interface from sending or receiving BPDUs.

What is RSTP port?

What is it? Rapid Spanning Tree Protocol (RSTP: IEEE 802.1w) is a network protocol that is an advancement over Spanning Tree Protocol (STP: IEEE802. 1D) that promotes high availability and “loop-free” topology within Ethernet networks.

How do you use a BPDU guard?

You can enable or disable the BPDU guard on per port basis….Configure the BPDU Guard

  1. Enter the interface configuration mode for the interface (0/1 in this example).
  2. Enable the BPDU guard on the port.
  3. Review the output for the BPDU guard on the port.
  4. Disable the BPDU guard on the interface.

How do you set a BPDU guard?

You can enable or disable the BPDU guard on per port basis….By default, the BPDU guard is disabled.

  1. Enter the interface configuration mode for the interface (0/1 in this example).
  2. Enable the BPDU guard on the port.
  3. Review the output for the BPDU guard on the port.
  4. Disable the BPDU guard on the interface.

Why is BPDU guard used?

BPDU Guard prevents switching devices from being accidentally connected to PortFast-enabled ports. If someone tries to connect an L2 device to the network, the BPDU guard ensures that it will be rejected.

When should BPDUfilter be used?

you would use bpdufilter when you want a switch plugged into your network but you don’t want it participating in spanning tree. An example: In an office environment where someone needs another network drop under their desk but you don’t have time/budget to run a new line for now.

What is BPDU guard in spanning tree?

Note When you enable BPDU guard on the switch, spanning tree applies BPDU guard to all PortFast-configured interfaces. BPDU filtering allows you to avoid transmitting BPDUs on PortFast-enabled ports that are connected to an end system.

How do I configure portfast BPDU guard on the switch?

The following sections describe how to configure PortFast BPDU guard on the switch. The PortFast feature is configured on an individual port, and the PortFast BPDU guard option is configured either globally or on a per-port basis. When you disable PortFast on a port, PortFast BPDU guard becomes inactive.

What to do when STP BPDU guard disables a port?

When STP BPDU guard disables the port, the port remains in the disabled state unless the port is enabled manually. You can configure a port to reenable itself automatically from the errdisable state. Issue these commands, which set the errdisable-timeout interval and enable the timeout feature:

What is the default BPDU filtering for each port?

By default, BPDU filtering is set for each port. This example shows how to enable PortFast BPDU filtering on the port and verify the configuration in PVST+ mode: received BPDUs. You may cause loops in the bridged network if you misuse