Once a portfast port receives a BPDU , it is supposed to lose portfast status and go back through the listening/learning phases at which point it is not forwarding traffic. Answer: If a Portfast enabled port receives BPDUs it will lose its Portfast status, regardless if configured on interface or globally.

What happens if a Portfast port receives a BPDU?

Once a portfast port receives a BPDU , it is supposed to lose portfast status and go back through the listening/learning phases at which point it is not forwarding traffic. Answer: If a Portfast enabled port receives BPDUs it will lose its Portfast status, regardless if configured on interface or globally.

Does Portfast port send BPDU? Part of the myth is also that portfast enabled ports do not send BPDUs. incrementing. Portfast is definitely enabled. … BPDUs are still sent on portfast enabled ports.

What happens to a switch port when a BPDU is received on it when BPDU Guard is enabled on that port?

BPDU Guard feature protects the port from receiving STP BPDUs, however the port can transmit STP BPDUs. When a STP BPDU is received on a BPDU Guard enabled port, the port is shutdown and the state of the port changes to ErrDis (Error-Disable) state.

What shuts down a port that receives a BPDU?

After BPDU protection is enabled on a switch, if an edge port on the switch receives a BPDU, the switch will shut down the edge port, while keeping the port attribute unchanged.

What is the difference between BPDU Guard and Root Guard?

BPDU Guard: Prevents accidental connection of switching devices to PortFast-enabled ports. … BPDU filtering: Restricts the switch from sending unnecessary BPDUs out access ports. Root Guard: Prevents switches connected on ports configured as access ports from becoming. the root switch.

What is difference between BPDU guard and BPDU filter?

BPDU filter will prevent inbound and outbound BPDU but will remove portfast state on a port if a BPDU is received. … On the other hand, BPDU Guard keeps an eye open for any BPDU’s entering the interfaces that are enabled this feature. The port will disable as soon as the first BPDU is received, by shutting the port down.

Does blocking port send BPDU?

A Blocked Port will only process received BPDUs from neighboring switches. A port that can be selected as Root Port or Designated Port will transition to Listening state. In this state the port will be allowed to send BPDUs as well so that it can actively participate in Spanning-tree.

How do I disable PortFast ports?

To disable PortFast and BPDU Guard uncheck the PortFast and BPDU Guard checkboxes. It is recommended to enable PortFast only on access port types. However, PortFast can be enabled on the trunk ports by selecting the Trunk checkbox in the WebUI.

When should I disable spanning tree?

The most common reason for disabling spanning tree is that the original 802.1D Spanning Tree Protocol (STP) goes through a fairly lengthy wait period from the time a port becomes electrically active to when it starts to pass traffic.

What happen when a host PC is connected to a switch access port that is set to Portfast mode?

Understanding How PortFast Works PortFast causes a switch or trunk port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states. … When you enable PortFast on a switch or trunk port, the port is immediately transitioned to the spanning tree forwarding state.

How do I know if my BPDU Guard is enabled?

To display the BPDU guard state, enter the show running configuration or the show stp-bpdu-guard command. For the BPDU status enter the stp-bpdu-guard command.

Is BPDU guard enabled by default?

spanning-tree portfast bpduguard default Globally enable BPDU guard. (By default, BPDU guard is disabled.) Note Globally enabling BPDU guard enables it only on STP ports; the command has no effect on ports that are not running STP.

How do I know if a port is spanning-tree blocking?

Use the show spanning-tree vlan command on all switches to find out which ports are in blocking or forwarding state and confirm your expected Layer 2 path.

What is STP BPDU?

(Bridge Protocol Data Unit) A spanning tree protocol (STP) message unit that describes the attributes of a switch port such as its MAC address, priority and cost to reach. BPDUs enable switches that participate in a spanning tree protocol to gather information about each other.

What is the purpose of STP BPDUs?

In a Layer 2 bridge environment, spanning-tree protocols use data frames called Bridge Protocol Data Units (BPDUs) to exchange information among bridges. Spanning-tree protocols on peer systems exchange BPDUs, which contain information about port roles, bridge IDs, and root path costs.