Which of the following describes the purpose of TCP in packet switching?

The purpose of TCP, or Transmission Control Protocol, in packet switching is fundamentally about managing how data is transmitted over a network. It is responsible for breaking larger pieces of data into smaller packets for efficient transmission across the network. Once these packets reach their destination, TCP ensures they are reassembled in the correct order, preserving the integrity and sequence of the original message.

This functionality is essential for reliable communication over networks, as packets can travel different routes and may arrive out of order. TCP not only splits the data but also provides mechanisms for error checking and connection management to confirm that packets are sent and received successfully. This makes it a critical component of internet communication, ensuring that data flows smoothly and accurately between devices.

The other options address different aspects of networking but do not pertain specifically to the role of TCP in packet switching. For example, secure communication and domain name translation are handled by different protocols, and device addressing relates more to network layer functions rather than the transport layer where TCP operates.