The Network Time Protocol (NTP) is a globally established standard for synchronizing the time between computers and other network-enabled devices via packet-switched networks such as the Internet or local corporate networks (LAN). NTP was developed in the 1980s by David L. Mills at the University of Delaware—making it one of the oldest Internet protocols still in active use today. The goal of NTP is to synchronize the system time of a wide variety of devices within a network as precisely as possible with a common reference time, typically Coordinated Universal Time (UTC).
How does NTP work?
NTP uses the connectionless UDP Transport Protocol (User Datagram Protocol) over port 123. Unlike connection-oriented protocols such as TCP, UDP does not establish a persistent connection, which allows time queries to be performed particularly quickly and with minimal overhead. An NTP client sends a time request to an NTP server, which in turn obtains its time from higher-level reference sources—such as atomic clocks, GPS receivers, or other high-precision time standards. These reference sources are organized into a hierarchical structure of so-called „stratum levels“: Stratum 0 denotes the actual time source (e.g., an atomic clock), Stratum 1 denotes the servers directly connected to it, and each subsequent level derives its time from the respective higher-level stratum. By exchanging multiple timestamps and calculating signal propagation times, NTP can compensate for network latencies and thus achieve accuracy in the millisecond range even over long distances—and in well-configured local networks, even in the sub-millisecond range.
Why is precise time synchronization important?
An accurate and consistent time is a fundamental requirement for many processes in IT systems and industrial facilities: from ensuring the correct order of log files to securing encrypted connections and precisely timing events in distributed systems. Especially in the Measurement technology Time synchronization is of central importance. When measurement data from multiple, geographically separated data acquisition devices is consolidated, all systems involved must share a common, precise time base. Only in this way can measurement values from different sources be correctly correlated, events be chronologically ordered, and cause-and-effect relationships be reliably analyzed. Even slight time deviations between individual measurement channels or devices can quickly lead to misinterpretations during evaluation, particularly when examining time-critical processes such as vibrations, disturbances, or switching operations.
NTP in Measurement Technology – Practical Applications at Delphin
The data loggers and measuring devices from Delphin Technology use NTP to automatically synchronize their internal real-time clock with a PC, network server, or public time server. This is particularly important when multiple devices at different locations collect measurement data decentrally, which must then be merged with the correct timestamps and evaluated together. If newly arriving measurement values are not displayed in a trend chart, the cause is often faulty NTP time synchronization—an issue that can be easily checked and adjusted using the devices’ configuration software.
Overview of the Benefits of NTP
- Automatic time synchronization: Devices synchronize their time automatically and at regular intervals, without any manual intervention.
- High accuracy: By compensating for network latency, precise time measurements are possible even across network boundaries.
- Low network overhead: The use of UDP makes NTP resource-efficient and fast.
- Scalability: NTP is suitable for both small, local measurement networks and globally distributed systems with many end devices.
- The foundation for reliable data analysis: Only measurement data that is correctly timed can provide reliable results during analysis, troubleshooting, or process optimization.
In measurement and automation technology, NTP forms the invisible but essential foundation for consistent, trustworthy measurement data—only devices that are accurately synchronized in time can deliver reliably comparable results.