CompTIA Network+ Practice Test 2026 - Free Network+ Practice Questions and Exam Prep Guide

When a fragment is lost during packet transmission, the entire packet must be resent. This is because network protocols, such as the Transmission Control Protocol (TCP), use a process called sequencing to ensure that all fragments of a packet are received in the correct order and are complete. If any fragment is missing, the receiving device cannot properly reassemble the original packet, leading to a requirement for retransmission of the whole packet.

The reason this occurs is due to how data is segmented for transmission. A packet is divided into smaller fragments to accommodate the Maximum Transmission Unit (MTU) of the network path. If a fragment is lost, the integrity of the entire message is compromised, as the receiving end needs every part to reconstitute the original data accurately.

In contrast, other options like resending only the lost fragment or rerouting the transmission wouldn't ensure the correct assembly of the data. Ignoring the lost packet with no consequences could lead to data loss, making it essential to resend the entire packet to maintain data integrity and reliability in communication.