Which protocol synchronizes computer clocks to UTC across NOCs?

• A. Time Protocol
• B. Time Synchronization Protocol
• C. Coordinated Time Protocol
• D. Network Time Protocol (NTP)

Answer: (D)

Network Time Protocol is what keeps clocks in sync with Coordinated Universal Time across multiple NOCs. It works by distributing UTC time through a hierarchical set of time sources (stratum levels) and exchanging time stamps between clients and servers to estimate the true offset and network delay. The local clock is then disciplined to stay aligned with UTC, and the protocol accounts for varying network latency, so even across distant locations the clocks remain consistently close to the same time. NTP is designed for network-wide synchronization, scales well from local networks to the Internet, and commonly runs over UDP port 123, making it the standard method for ensuring uniform timestamps across systems.