Which statement best describes the client-server model in NTP?

• A. It uses only client-server architecture
• B. It relies on a central master clock
• C. It is purely a unidirectional timing protocol
• D. It describes how NTP usually operates, but it can also function in peer-to-peer relationships

Answer: (D)

NTP is built to work well in a client-server setup, where clients query servers to obtain the correct time and discipline their own clocks based on the replies. But it isn’t limited to that pattern. It can also operate in symmetric, peer-to-peer relationships where two servers exchange timing information and each can act as both a client and a server. This peer mode allows two clocks to adjust against one another or against a common reference without relying on a single central master, increasing redundancy and resilience. The idea that NTP relies on a single central master or that it is purely unidirectional doesn’t fit how the protocol actually works, because clients and servers continually exchange timestamps bidirectionally, and multiple sources can be used to align clocks.