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NTP module: Difference between revisions
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Add information about Jitter and Peer dispersion
(Use correct column description for stratum) |
(Add information about Jitter and Peer dispersion) |
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This is the maximum error relative to the primary reference source at the root of this subnet. | This is the maximum error relative to the primary reference source at the root of this subnet. | ||
'''Peer dispersion''' | |||
This is the maximum error of the peer clock relative to the local clock over the network path between them. | |||
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The number of NTP users that use this clock as a reference. | The number of NTP users that use this clock as a reference. | ||
'''Jitter''' | |||
The jitter (psi) is defined as the root-mean-square (RMS) average of the most recent offset differences, and it represents the nominal error in estimating the offset. Jitter is a quantity calculated for each server/client pair. The min/med/max values are the minimum/median/maximum jitter of all the clients that have connected to the server. | |||
'''Remark for chrony users''' | '''Remark for chrony users''' | ||
Chrony sets the reference timestamp to zero and the received/transmit timestamp to a random value. Only the origin timestamp is correct. | Chrony sets the reference timestamp to zero and the received/transmit timestamp to a random value. Only the origin timestamp is correct. This also causes the jitter calculation to become invalid since the exact timestamps are needed. | ||