What does spanning tree Bpduguard enable mean?

BPDU Guard is a feature that defends the Layer 2 Spanning Tree Protocol (STP) topology against BPDU-related threats and is designed to protect the switching network. The BPDU guard feature must be activated on ports that should not receive BPDUs from connected devices.

What is Portfast Bpduguard?

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 the purpose of BPDU guard?

The BPDU guard, an enhancement to STP, removes a node that reflects BPDUs back in the network. It enforces the STP domain borders and keeps the active topology predictable by not allowing any network devices behind a BPDU guard-enabled port to participate in STP.

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 when a PortFast port receives a BPDU?

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

What is spanning tree PortFast used for?

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.

What is PortFast?

PortFast is a Cisco feature for PVST+ environments. When a switch port is configured with PortFast that port transitions from blocking to forwarding state immediately, bypassing the usual 802.1D STP transition states (the listening and learning states).

What is a BPDU packet?

Acronym for bridge protocol data unit. BPDUs are data messages that are exchanged across the switches within an extended LAN that uses a spanning tree protocol topology. BPDU packets contain information on ports, addresses, priorities and costs and ensure that the data ends up where it was intended to go.

What is Portfast in Cisco switch?

Portfast feature causes a switch port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states.

What is spanning-tree Portfast used for?

When should you 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.

What is the default timers of convergence in STP?

STP Timers :

Timer Default Value
Hello 2 seconds
MaxAge 10*Hello time
Forward Delay 15 seconds

Does the Global Command spanning-tree portfast bpduguard default apply to Trunk ports?

It is my understanding that when configuring the global command spanning-tree portfast bpduguard default this will only apply BPDUguard only on ports already configured with the portfast command and not on trunk ports.

What happens 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.

What is portfast BPDU guard?

If a PortFast-configured interface receives a BPDU, an invalid configuration exists. BPDU guard provides a secure response to invalid configurations because the administrator must manually put the interface back in service.

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