Cisco NTP basics
NTP is a protocol designed to synchronize clock with a atomic- or a radio clock.
The NTP Protocol uses the current standard of protocol version 4.
NTP is reserved for the UDP-Port 123.
The timestamp at NTP are 64bit long. 32 bits encode the seconds since the beginning of 1. Januar 1900 00:00:00. The next 32 bits are the fraction of the seconds.
With this manner it is possible to calculate the time in a resolution of 2 -32 seconds.
NTP uses a hierarchical system of serveral strata. stratum 0 is called
time normal for example for an antomic- or a radio clock. The directly connected NTP-Server are called stratum 1.
Each furhter dependent unit get the next higher incemental. see the following figure.