Time Servers
Timing and Synchronization Solutions
Precision timing is critical for defense, commercial industries, and powering essential network operations. Safran offers comprehensive network time servers and solutions for precise synchronization, security, compliance, and adherence to resilient timing best practices. Whenever accuracy, safety, security and reliability are critical, Safran NTP appliances leads the way.
White Rabbit Timing
White Rabbit Timing
White Rabbit is a collaborative project including CERN (the European Organization for Nuclear Research), GSI Helmholtz Centre for Heavy Ion Research and other partners to develop a fully deterministic Ethernet-based network for general purpose data transfer and sub-nanosecond accuracy time transfer.
Network time synchronization is secure, reliable & accurate when:
– 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 time synchronize the time across a network
– Its behind the firewall to protect against unauthorized access and the threat of cyber attacks
– Its a highly accurate 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
NTP Stratum Levels and Accuracy
What is NTP (network time protocol)?
NTP 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 vs. SNTP: What’s the Difference?
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 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 synchronization 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 time 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 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.