How accurate is NTP?
Over WANs (Wide Area Networks), up to 100 milliseconds is typical. It depends on how far away the public time server is, or more specifically, how many hops between you and the server. Within a LAN (Local Area Network) using a dedicated NTP Time Server, 0.5 to 2 milliseconds is typical. The internal accuracy of the CDMA Network Time Server is on the order of 10 microseconds. It can easily keep all clients on a LAN synchronized to typically within 0.5 to 2 milliseconds.
It depends on how many hops occur between client and server, and other network latency inducing factors. Over Wide Area Networks, WANs, 10 to 100 milliseconds is typical. Within a Local Area Network, LAN, 0.5 to two milliseconds is typical. However, when operating with the SyncServer® models with GPS, the internal clock accuracy is less than 50 nanoseconds and the NTP time stamp accuracy at the NTP port is less than 14 microseconds.