TIMED(8,C) AIX TCP/IP User's Guide TIMED(8,C)
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timed
PURPOSE
Provides network time service.
SYNTAX
+----------------+
/etc/timed ---| +------------+ |---|
+-| -t |-+
^| -M ||
|| -n network ||
|| -i network ||
|+------------+|
+--------------+
DESCRIPTION
The timed server command is the time server daemon and is normally invoked at
boot time from the rc.tcpip file. It coordinates the host's time with the time
of other machines in a local area network running the timed program. These
time servers slow down the clocks of some machines and speed up the clocks of
others to bring them to the average network time. The average network time is
computed from measurements of clock differences using the ICMP time stamp
request message.
The service provided by the timed command is based on a master-slave scheme.
When timed is started on a machine, it asks the master for the network time and
sets the host's clock to that time. After that, it accepts synchronization
messages periodically sent by the master and calls adjtime (for information on
adjtime, refer to AIX Operating System Technical Reference) to perform the
needed corrections on the host's clock.
To select a host as a master timed server, the file /local/timedmaster must
exist on the host. Typing "touch /local/timedmaster" will create the file.
It also communicates with date (refer to AIX Operating System Commands
Reference) in order to set the date globally, and with timedc, a timed control
program. If the machine running the master crashes, then the slaves elect a
new master from among slaves running with the -M flag. A timed running without
the -M flag remains a slave. The -t flag enables timed to trace the messages
it receives in the file /usr/adm/timed.log. Tracing can be turned on or off by
the program timedc. timed normally checks for a master time server on each
network to which it is connected, except as modified by the options described
here.
Processed October 29, 1990 TIMED(8,C) 1
TIMED(8,C) AIX TCP/IP User's Guide TIMED(8,C)
It requests synchronization service from the first master server located. If
permitted by the -M flag, it provides synchronization service on any attached
networks on which no current master server was detected. Such a server
propagates the time computed by the top-level master. The -n flag, followed by
the name of a network which the host is connected to (see "networks"),
overrides the default choice of the network addresses created by the program.
Each time the -n flag appears, that network name is added to a list of valid
networks. All other networks are ignored. The -i flag, followed by the name of
a network to which the host is connected (see "networks"), overrides the
default choice of the network addresses made by the program. Each time the -i
flag appears, that network name is added to a list of networks to ignore. All
other networks are used by the time daemon. The -n and -i flags are
meaningless if used together.
FLAGS
The timed command options are:
-i Overrides the default choice of network addresses created by the program
when followed by the name of a network to which the host is connected.
Each time the -i flag appears, that network name is added to a list of
networks to ignore.
-M Creates a new master from among slaves, if the machine running the
master crashes. Only one master site can exist at any one time. A
timed running without the -M remains a slave.
-n Overrides the default choice of the network addresses created by the
program when followed by the name of a network which the host is
connected.
-t Enables timed to trace the messages it receives in the file
/usr/adm/timed.log.
FILES
/usr/adm/timed.log tracing file for timed
/local/timedmaster identifies master timed server
RELATED INFORMATION
In this book: "timedc"
date, refer to AIX Operating System Commands Reference
adjtime, refer to AIX Operating System Technical Reference
gettimeofday, refer to AIX Operating System Technical Reference
Processed October 29, 1990 TIMED(8,C) 2