Which feature will protect a switch immediately if it sees another switch's advertisement?

BPDU Guard will turn the interface to err-disable as soon as a BPDU is heard on the interface. This feature should be enabled on access switches when configuring PortFast. There is no feature called BPDU Detection. Loop Guard is used in conjunction with BPDU Guard for additional protection by monitoring and tracking BPDUs. UplinkFast is a Cisco-proprietary feature that improves convergence times for Spanning Tree.