This documentation uses the following terms:
NTP time provider: A server that uses the Network Time Protocol (NTP) protocol and provides NTP time to other servers or to workstations on the network.
The time provider gives time to operating systems that are NTP and NCP compliant, such as the following:
NetWare 4.2, 5.0, 5.1, 6.0, and 6.5
All flavors of UNIX
All versions of Windows* that have NTP compliance
The time provider can broadcast or multicast its services on the network. For more information, see Section 3.3, Broadcast and Multicast Mode.
NTP time consumer: A server that understands the NTP protocol and seeks NTP time from an NTP time provider to synchronize its time.
The time consumer can accept a time provider in the client-server, peer-peer, and multicast/broadcast modes. For more information, see Section 3.1, Client-Server Mode, Section 3.2, Peer-to-Peer Mode, and Section 3.3, Broadcast and Multicast Mode.
The time consumer can work with operating systems that are NTP and NCPcompliant, such as the following:
NetWare 5.1, 6.0, and 6.5
All flavors of UNIX
All versions of Windows that have NTP compliance
Time provider group: A set of servers that are configured to ensure fault tolerance and optimal network usage.
The time provider group can be configured to keep the network traffic at a minimum.
Dispersion: A measure (in seconds) of how scattered the time offsets are from a given time server.
Drift: A measure (in hertz per second) of how quickly the skew of a clock changes.
See also Slew:.
Jitter: Small rapid variations in a waveform because of fluctuations in the voltage supply, mechanical vibrations, or other sources.
Minpoll: Specifies the minimum polling interval (in seconds to the power of 2) for NTP messages. If you set minpoll to 4, the minimum polling interval reduces. A value of 4 with minpoll helps the server to synchronize within a minute.
The default minpoll value is 4 on NetWare and 6 on UNIX.
Root delay: The total round trip delay (in seconds) to the primary reference source at the root of the synchronization subnet. This variable can take on both positive and negative values, depending on clock precision and skew.
Root dispersion: The maximum error (in seconds) relative to the primary reference source at the root of the synchronization subnet. This variable can take only positive values greater than zero.
Skew: A measure (in hertz) of the difference between the actual frequency of a clock and its frequency to keep perfect time.
See also Drift:.
Slam: To immediately correct or adjust the time of a clock. This might lead to sudden bursts in time.
Step: To change the time of a clock to the correct time with no intermediate adjustments.
See Skew:.
Slew: To gradually adjust the time of a clock until it displays the correct time.
See Step:.
Stratum: Conventions established to indicate the accuracy of each time server, defined by a number called the stratum, with the topmost level (PRIMARY Servers) assigned as one and each level downwards (SECONDARY Servers) in the hierarchy assigned as one greater than the preceding level.