Time Servers

Accurate time keeping is crucial, as many network events, from process control to authentication, depend on precise timing. Reliable timestamps and log files are essential for billing systems, diagnostics, forensics, and databases. However, the internal clocks of electronic devices often drift over time, leading to inaccuracies. The solution is network time synchronization, which relies on a designated NTP appliance as the master clock and reference point.

You can trust Safran enterprise NTP servers for security, reliability, accuracy, and manageability of efficient network operations.

– The network time sync occurs between servers and clients via Network Time Protocol (NTP)
– A master time source, known as an NTP server, is used to synchronize the time across a network
– Its behind the firewall to protect against unauthorized access and the threat of cyber attacks
– Its a stratum-1 NTP server, which syncs directly with national time standards
– The NTP clock server is available 24/7 for continuous, reliable time synchronization across the network

Stratum levels are used to indicate the traceability path from the atomic clocks operated by national standards organizations. These “official time clocks” are defined as stratum-0 clocks as they are the most accurate. However stratum-0 time sources can not be used on a network. Stratum-1 time sources are directly traceable to national standards. Stratum-1 timing servers get their time by direct connection to atomic clocks through GPS transmissions, long-wave radio signals such as WWV, or dial-up modem.

Stratum-1 timeservers act as the primary network time standard. Stratum-2 servers get their time from stratum 1 sources, and so on. Higher stratum levels (stratum-2, stratum-3, stratum-4, etc) are deemed less accurate than their source because of transmission delays by about 10-100 milliseconds per stratum level. Typically GPS NTP servers use the broadcast as the primary source of official time, although other time sources can be used as primary or as back-up to GPS time as is the case with dial-up modem.

SecureSyncs are stratum-1 best NTP servers that offer the accuracy, reliability and security that you need for an efficient and reliable network.

NTP, which stands for Network Time Protocol, is a UDP protocol for IP networks. The Internet Engineering Task Force has formalized the current standard of NTP (version 4) in RFC 5905. Simple network time protocol, SNTP, the latest standard formalized as RFC 4330, uses a less complex client implementation. A server / master clock solution requires client software to read NTP packets generated by an NTP server and synchronize the local clock.

NTP (Network Time Protocol) and SNTP (Simple Network Time Protocol) are similar TCP/IP protocols in that they use the same time packet from a global time server message to compute accurate time. The procedure used to assemble and send out a time stamp is exactly the same whether NTP (i.e., full implementation NTP) is used, or SNTP is used. The difference between NTP and SNTP is important in the time synch program running on the client side on each system. Whether it is a Windows built-in program like W32Time (which uses the SNTP protocol) or a third-party add-on, determines which protocol is being used — not the NTP server. The difference between NTP and SNTP is in the error checking and the algorithm for the actual correction to the time itself.

The NTP algorithm is much more complicated than the SNTP algorithm. NTP normally uses multiple clock servers to verify the time and then controls the slew rate of the system. The algorithm determines if the values are accurate using several methods, including fudge factors and identifying GPS time servers that don’t agree with others. It then speeds up or slows down the system clock’s drift rate so that (1) the system’s time is always correct and (2) there won’t be any subsequent time jumps after the initial correction. Unlike NTP servers, SNTP servers typically use one server to calculate the time, then “jumps” the system time to the calculated time. It can, however, have back-up appliances in case one is not available. During each interval, it determines whether the time is off enough to make a correction and if it is, applies the correction.

In general, SNTP clients should only be used where time synchronization is not critical for your systems. For all other clients, and for systems that will also serve time to other systems, you should utilize full NTP implementations to include reference selection and clock steering algorithms to maintain accuracy through the full timing path.

Looking at the timeservers themselves, the selection of a worldwide time server that uses SNTP or NTP to serve time only should focus on whether it would ever synchronize to NTP as a primary or secondary reference — in which case, only full NTP should be used. To simplify things, SNTP should be used only at the start or end of the network timing path, and only at the end of the network timing path where time sync is not critical for your systems.