A network administrator is expanding a network and wants to ensure no unauthorized redundant links are present. Which of the following should the administrator use to identify and block redundant…

Software-Defined Networking (SDN) is an architectural approach to networking that separates the control plane from the data plane, which can manage network paths but is not primarily used for identifying and blocking redundant links to prevent loops at Layer 2.

Spanning Tree Protocol (STP) is a Layer 2 network protocol that actively detects and blocks redundant paths in an Ethernet network. It works by placing redundant ports in a blocking state, thereby preventing broadcast storms, MAC address table instability, and ensuring a loop-free logical topology while still allowing for physical redundancy and fault tolerance.

Link Layer Discovery Protocol (LLDP) is used by network devices to advertise their identity, capabilities, and neighbors on a local area network, primarily for discovery and troubleshooting, not for preventing network loops.

Open Shortest Path First (OSPF) is a Layer 3 routing protocol used to find the best path for packet delivery in an IP network, not for preventing Layer 2 switching loops caused by redundant links.