What is NTP? (Network Time Protocol) Simplified In 5 Points

Ajay Ohri


Business/IT related operational processes are mostly time-dependant and occur within their own networks. Even, applications supporting enterprises and e-business processes are time-dependent since they conduct their operations and functions over the Internet. Hence time must be a factor that is synchronized globally. What is NTP is then precisely what the NTP server does to alleviate this requirement.

  1. What is NTP Server?
  2. Why should I synchronize my network?
  3. What’s important in selecting a Network Time Server?
  4. What is ACTS?
  5. What is the Network Time Protocol?

1. What is NTP Server?

What is NTP protocol? A ‘network time server’ is a general description of the software on the NTP- Network Time Protocol server which is running on any server/computer platform. It is applied to the network appliance (tray mount, rack etc), which acquires and uses time from an external source to maintain time within its local internal clock, and then supply the time its connected network. This is achieved using the NTP or Network Time Protocol.

2. Why should I synchronize my network?

Applications have time-stamping of 1 millisecond to 1 second and often its accuracy reflects the chain of events or order of occurrence.  In today’s technologically advanced world even a one-millisecond difference is not tolerated. Timestamps in what is NTP, hence provide the order of events and occurrences accurately and hence the need to synchronize the NTP server and its NTP pool network.

All operations on the network requiring high accuracy in operations are typically time-stamped in the order of 1-10 milliseconds. By using NTP sync to synchronize the NTP server, one can use its common built-in time-base to record time accurately and hence avoid expensive downtime problems. An example of a transaction needing accurate time processing on an NTP server port is network recovery and fault diagnosis in software development. 

3. What’s important in selecting a Network Time Server?

When selecting a service or product, one must understand what is NTP server and look into the network time servers critical features allowing what is NTP to make a huge difference. They are:

  • Multiple NTP ports: Using a time server that provides multiple NTP ports supports modern and what is NTP stratum networks being synchronized using such an NTP protocol port with the time server in a secure environment conducive to upgrading.
  • Atomic Clock Upgrade: Time servers using GPS signals for NTP server address should use a Rubidium internal atomic oscillator which prevents loss of accuracy when the GPS signal is jammed or lost while maintaining accurate time on the NTP client time server.
  • Redundant time sources: The network needs to be synchronized to a Reference Clock Source dedicated network time server to avoid redundancy and ensure the network reflects the accurate time.
  • Time cross-check: It should include automatic system clock checks against a third-party clock. When NTP time sync server is off the limits set, it changes the time to the best reference value while notifying the user via the SNMP.
  • NTP accuracy and request throughput: Large NTP networks enjoy the ability to synchronize multiple clients and handle coincidental peak load of NTP requests.
  • Easy to use: The keypads are easy to set up and use, while the provision of the SNMP ensures prompt notifications and the browser interface allows for intuitive access remotely.
  • Single Satellite/ Window Antenna Timing: In urban environments where access to the roof is restricted or where satellite visibility may suffer and be limited, the provision of the single satellite automatic timing mode on the NTP server, maintains accurate time even with intermittent satellite signals and through use of window-mounted antennae to track satellites.

4. What is ACTS?

ACTS is the acronym for Automated Computer Time Service. The service is provided by the Colorado-based NIST- National Institute of Standards and Technology located at Boulder. Using the service, NTP servers can execute telephone-linked NIST/ UTC time-transfers over a dialup service. NTP servers S300/S350 with a built-in time server modem is an example of the ACTS service in what is NTP. Japan, many European countries provide such dial-up services.

5. What is the Network Time Protocol?

NTP stands for the acronym for Network Time Protocol and is an IP Networks UDP protocol. It is used to synchronize the client machines clock with the network time server’s clock. NTP being a protocol needs separate server and client applications for its implementation. 

  • How NTP works: Dr David Mills of the University of Delaware under contract to DARPA developed the open-source free-to-use protocol. The NTP software operates in server or client mode or both and uses NTP daemon software. How to sync time with NTP server? The purpose of NTP is to use the time server’s local clock to relatively reveal and set the client’s local clock offset. The client-server sends a UDP time request packet to the host time NTP server which gets time-stamped and then returned to the client. The client-server then computes the offset of the local clock on it using the time server’s timestamp to make adjustments. The robust NTP algorithm is quite complicated and has features like prioritizing multiple servers, self-healing and adjusting for network latencies. Version 1 was launched in 1985.
  • How to check NTP server in Linux? In an example of how NTP is server implemented the client application running on Linux or Windows workstations, use the NTP packets to exchange timestamp data between server and client time servers. The time server thus sets the client clock on the client-server machine extremely accurately to the time server’s time in a process called synchronization. 
  • What is the use of NTP server? Note that the purpose of NTP is ONLY to reveal the offset on the client clock and NOT to deliver time. The OS-operating system is responsible for time delivery. The NTP application program on the client-server has complex processes to compute the offset in time and then adjust the clock on the client-server. The hardware implementation of the protocol and computer clocks is different in different computers. Most third party computers use NTP servers with an inbuilt clock. If the system is a non-NTP aware OS then one will need to download and install the NTP protocol or NTP UNIX which needs technical instructions and is best done by a professional.
  • NTP Accuracy: Accuracy depends on the number of hops that happen between server and client and network latency factors. Over a WAN or Wide Area Networks, this can be 1 to 10 milliseconds. On a LAN- Local Area Network, it varies from 0.5 to 2 milliseconds. When GPS is used the internal clock accuracy is less than 50 nanoseconds. With GPS signals to the NTP, the NTP port’s timestamp accuracy is less than 14 microseconds in what is NTP.
  • Differences between NTP and SNTP clients: What is SNTP? SNTP- Simple Network Time Protocol is based on RFC 1361/2030 SNTP server which gets its time from a specific pre-installed machine’s time server. Its protocol cannot be changed or re-configured to obtain timestamps from a different time server when the primary time server is down. Hence it is also called a short NTP version of client software. The NTP- Network Time Protocol uses built-in algorithms to configure, obtain and distribute network time with an accuracy of 0.5-3 milliseconds. Its algorithm is amenable to being configured to get timestamps from an alternate time server in case the original server is out of synchronization or fails.
  • What is NTP configuration: If the operating system has in-built NTP one can enable the capability using NTP daemon on a *nix system. For this one need not run the NIX computer but rather one uses the NTP client software for synchronization of the time server. Modern versions of time servers like Symmetricom, use NTP software which provides Domain Time II software for monitoring, management and time client synchronization. The latest version of NTP can be downloaded at  http:/www.ntp.org/. The NTP Daemon for *nix systems can be downloaded at http:/www.ntp.org. 


In conclusion, the accuracy, security, ease of use and reliability of the dedicated network time server is very important to what is NTP and the NTP time server.

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