In the context of the OSI model of computer networks, which of the following…
2023
In the context of the OSI model of computer networks, which of the following statements name a transport-layer protocol?
I. Transmission Control Protocol (TCP)
II. User Datagram Protocol (UDP)
Answer: C. Both I and II — ConceptThe transport layer provides end-to-end communication between application processes. In the Internet protocol suite, TCP and UDP are its two principal…
- A.
Only I
- B.
Neither I nor II
- C.
Both I and II
- D.
Only II
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Show answer & explanation
Correct answer: C
Concept
The transport layer provides end-to-end communication between application processes. In the Internet protocol suite, TCP and UDP are its two principal protocols.
TCP expands to Transmission Control Protocol and provides reliable, connection-oriented byte-stream service. UDP expands to User Datagram Protocol and provides connectionless datagram service.
Application
Statement I names Transmission Control Protocol (TCP), which operates at the transport layer.
Statement II names User Datagram Protocol (UDP), which also operates at the transport layer.
Therefore, the two statements identify transport-layer protocols.
Contrast and cross-check
‘Only I’ omits UDP even though UDP supplies transport-layer datagram service.
‘Neither I nor II’ excludes both established transport-layer protocols.
‘Only II’ omits TCP even though TCP supplies transport-layer byte-stream service.
RFC 9293 defines TCP, and RFC 768 defines UDP; both belong to the Internet transport layer.
Result
The answer by value is ‘Both I and II’.