Which of the following transport layer protocols is used to support electronic mail?
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Answer: C
To identify the correct transport layer protocol used for electronic mail, let us analyze the layer and function of each given option:
- SMTP (Simple Mail Transfer Protocol): This is an Application Layer protocol used for sending and receiving email. Although it is the primary protocol for email, it is not a transport layer protocol.
- IP (Internet Protocol): This is a Network Layer protocol responsible for addressing and routing packets across network boundaries.
- TCP (Transmission Control Protocol): This is a Transport Layer protocol that provides reliable, connection-oriented, and ordered delivery of data. Since email transmission requires absolute reliability (no lost messages or corrupted text), SMTP relies on TCP at the transport layer (typically on port 25).
- UDP (User Datagram Protocol): This is a connectionless, unreliable Transport Layer protocol. It is not suitable for email because packet loss cannot be tolerated in email delivery.
Therefore, TCP is the transport layer protocol used to support electronic mail.
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