NTP - Sysinfo
NTP - Sysinfo
NTPDaemonStatus
This page displays the status of the NTP daemon. Many of the fields below are based on the
NTP Packet
(on page 198). Also see http://www.ntp.org.
system peer
: The IP address of the clock source. The source is selected by the NTP dae-
mon that is most likely to provide the best timing information based on: stratum, distance, dis-
persion and confidence interval. The system peer identified as "SYMM_TE(0)" is the local
SyncServer Hardware Clock. Also see
Hardware Clock
(on page 196).
system peer mode
: The relationship of the SyncServer to a system peer, usually a "client".
Depending the configuration, the mode can be:
n
Client:
A host operating in this mode sends periodic messages regardless of the reach-
ability state or stratum of its peer. By operating in this mode the host, usually a LAN work-
station, announces its willingness to be synchronized by, but not to synchronize the peer.
n
Symmetric Active:
A host operating in this mode sends periodic messages regardless
of the reachability state or stratum of its peer. By operating in this mode the host
announces its willingness to synchronize and be synchronized by the peer.
n
Symmetric Passive:
This type of association is ordinarily created upon arrival of a mes-
sage from a peer operating in the symmetric active mode and persists only as long as the
peer is reachable and operating at a stratum level less than or equal to the host; oth-
erwise, the association is dissolved. However, the association will always persist until at
least one message has been sent in reply. By operating in this mode the host announces
its willingness to synchronize and be synchronized by the peer.
A host operating in client mode (a workstation, for example) occasionally sends an NTP mes-
sage to a host operating in server mode (the SyncServer), perhaps right after rebooting and
at periodic intervals thereafter. The server responds by simply interchanging addresses and
ports, filling in the required time information and returning the message to the client. Servers
need retain no state information between client requests, while clients are free to manage
the intervals between sending NTP messages to suit local conditions.
In the symmetric modes, the client/server distinction (almost) disappears. Symmetric passive
mode is intended for use by time servers operating near the root nodes (lowest stratum) of
the synchronization subnet and with a relatively large number of peers on an intermittent
basis. In this mode the identity of the peer need not be known in advance, since the asso-
ciation with its state variables is created only when an NTP message arrives. Furthermore,
the state storage can be reused when the peer becomes unreachable or is operating at a
higher stratum level and thus ineligible as a synchronization source.
Symmetric active mode is intended for use by time servers operating near the end nodes
(highest stratum) of the synchronization subnet. Reliable time service can usually be main-
tained with two peers at the next lower stratum level and one peer at the same stratum level,
so the rate of ongoing polls is usually not significant, even when connectivity is lost and error
messages are being returned for every poll.
leap indicator (LI):
997-01520-02 Rev. F1
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