Which two protocols implement the OSI Transport layer in the TCP/IP model?

Which two protocols implement the OSI Transport layer in the TCP/IP model?

• A. IP and ICMP
• B. HTTP and FTP
• C. DNS and TLS
• D. TCP and UDP

Answer: (D)

The Transport layer in TCP/IP is the layer that handles end-to-end communication between processes, providing services that determine how data is delivered from one host to another. The two protocols that implement these transport services are Transmission Control Protocol and User Datagram Protocol. TCP offers a connection-oriented, reliable service: it establishes a connection, breaks data into segments, and uses acknowledgments, sequencing, and flow control to ensure data arrives correctly and in order. UDP, on the other hand, provides a lightweight, connectionless, best-effort service with minimal overhead and no guarantees of delivery, order, or error checking. Other protocols you might see belong to different layers: IP (and ICMP) are at the Internet/Network layer and handle routing and control messages, while HTTP, FTP, DNS, and TLS are application-layer protocols that rely on the transport layer to move their data, with TLS operating on top of TCP as a security layer rather than replacing the transport mechanism.

The Transport layer in TCP/IP is the layer that handles end-to-end communication between processes, providing services that determine how data is delivered from one host to another. The two protocols that implement these transport services are Transmission Control Protocol and User Datagram Protocol.

TCP offers a connection-oriented, reliable service: it establishes a connection, breaks data into segments, and uses acknowledgments, sequencing, and flow control to ensure data arrives correctly and in order. UDP, on the other hand, provides a lightweight, connectionless, best-effort service with minimal overhead and no guarantees of delivery, order, or error checking.

Other protocols you might see belong to different layers: IP (and ICMP) are at the Internet/Network layer and handle routing and control messages, while HTTP, FTP, DNS, and TLS are application-layer protocols that rely on the transport layer to move their data, with TLS operating on top of TCP as a security layer rather than replacing the transport mechanism.