Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for computer networks. It is crucial for the operation of Ethernet networks, where multiple paths can create routing loops. This protocol allows switches and bridges to communicate with one another and determine the most efficient path for data transmission. STP is a fundamental protocol used in a variety of networking applications, including local area networks (LANs) and wide area networks (WANs). By learning about STP, network engineers can better understand network design and improve network reliability.