In the context of computer networks, which one of the following is not

In the context of computer networks, which one of the following is not an application layer protocol?

SMTP
FTP
HTTP
TCP
This question was previously asked in
UPSC CISF-AC-EXE – 2019
The correct option is D.
In the context of computer networks using the TCP/IP model, the Application Layer is the highest layer, which interacts directly with software applications. Protocols at this layer provide specific services to applications. SMTP (Simple Mail Transfer Protocol), FTP (File Transfer Protocol), and HTTP (Hypertext Transfer Protocol) are all well-known application layer protocols used for email, file transfer, and web browsing, respectively. TCP (Transmission Control Protocol), on the other hand, is a Transport Layer protocol. It provides reliable, connection-oriented data transmission services to the application layer, ensuring data integrity and flow control.
The TCP/IP model consists of four layers: Network Interface Layer, Internet Layer, Transport Layer, and Application Layer. The Transport Layer is responsible for end-to-end data transfer between processes. Other common Transport Layer protocols include UDP (User Datagram Protocol).