Cisco Catalyst Feature: Automatically Disabling PortFast Upon Receipt of a BPDU

PortFast Feature of Cisco Catalyst

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Which Cisco Catalyst feature automatically disables the port in an operational PortFast upon receipt of a BPDU?



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A. B. C. D. E.


The correct answer is D. BPDU Guard.

PortFast is a feature on Cisco Catalyst switches that is used to enable rapid STP (Spanning Tree Protocol) convergence on ports connected to end devices such as workstations or servers. When PortFast is enabled on a port, it immediately transitions the port to the forwarding state without going through the normal STP listening and learning states.

However, if a BPDU (Bridge Protocol Data Unit) is received on a PortFast-enabled port, it indicates the presence of another switch or bridge on that port, which can cause loops in the network. To prevent this, Cisco Catalyst switches provide a feature called BPDU Guard, which automatically disables the PortFast-enabled port upon receipt of a BPDU.

BPDU Guard can be configured on a per-port basis, and it is typically used in conjunction with PortFast to ensure that no other switches or bridges are connected to a PortFast-enabled port. BPDU Guard can also be used to protect the network against rogue switches or bridges that may be introduced into the network by unauthorized users.

In summary, BPDU Guard is a Cisco Catalyst feature that automatically disables the port in an operational PortFast upon receipt of a BPDU, to prevent loops in the network and ensure network stability.