A network administrator needs to implement trunk port redundancy.

Link Aggregation Control Protocol, or LACP, is the correct technology because it allows multiple physical links between switches to operate as one logical link. This provides redundancy and can increase throughput by distributing traffic across bundled links. If one physical link in the bundle fails, traffic can continue over the remaining links. Since the bundled links are treated as a single logical connection, LACP also helps avoid Layer 2 switching loops that would otherwise occur if multiple independent trunk links were connected between the same switches.

The CompTIA Network+ N10-009 objectives include switching, trunking, redundancy, link aggregation, and loop prevention. LACP is based on IEEE 802.3ad/802.1AX and is commonly used between switches, servers, and network appliances to improve availability and bandwidth.

MDIX automatically adjusts transmit and receive pairs on copper Ethernet links, but it does not provide trunk redundancy or increased throughput. First Hop Redundancy Protocol provides default gateway redundancy, not trunk link aggregation. Spanning Tree Protocol prevents loops, but it may block redundant links and does not increase throughput. Therefore, LACP is the best answer.