Ntp not updating system clock
Ntp not updating system clock - updating xp key
Stratum 1 servers may peer with other stratum 1 servers for sanity check and backup.
NTP uses a hierarchical, semi-layered system of time sources.
The number represents the distance from the reference clock and is used to prevent cyclical dependencies in the hierarchy.
Stratum is not always an indication of quality or reliability; it is common to find stratum 3 time sources that are higher quality than other stratum 2 time sources.
NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions.
Asymmetric routes and network congestion can cause errors of 100 ms or more.
According to Mills, "the 64 bit value for the fraction is enough to resolve the amount of time it takes a photon to pass an electron at the speed of light.
The 64 bit second value is enough to provide unambiguous time representation until the universe goes dim." A typical NTP client will regularly poll three or more servers on diverse networks.Future versions of NTP may extend the time representation to 128 bits: 64 bits for the second and 64 bits for the fractional-second.The current NTPv4 format has support for Era Number and Era Offset, that when used properly should aid fixing date rollover issues.Each level of this hierarchy is termed a stratum and is assigned a number starting with zero for the reference clock at the top.A server synchronized to a stratum n server runs at stratum n 1.The technology was first deployed in a local area network as part of the Hello routing protocol and implemented in the Fuzzball router, an experimental operating system used in network prototyping, where it ran for many years.