timed(ADMN)                     19 June 1992                     timed(ADMN)


 Name

    timed - time server daemon

 Syntax

    /etc/timed [ -t ] [ -M ] [ -n network ] [ -i network ]

 Description


    timed is the time server daemon and is normally invoked at boot time from
    the STREAMS TCP/IP startup script.  It synchronizes the host's time with
    the time of other machines in a local area network running timed(ADMN).
    These time servers will 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 timestamp request message.

    The service provided by timed is based  on a master-slave scheme.  When
    timed(ADMN) 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 syn-
    chronization messages periodically sent by the master and calls
    adjtime(SSC) to perform the needed corrections on the host's clock.

    It also communicates with rdate(ADMN) to set the date globally, and with
    timedc(ADMN), a timed control program.  If the machine running the master
    crashes, then the slaves will elect a new master from among slaves run-
    ning with the -M flag.  A timed running without the -M flag will remain 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 pro-
    gram timedc(ADMN).

    Normally, timed checks for a master time server on each network to which
    it is connected, except as modified by the options described below.  It
    will request synchronization service from the first master server
    located.  If permitted by the -M flag, it will provide 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(SFF)), overrides the default choice of the
    network addresses made by the program.  Each time the -n flag appears,
    that network name is added to a list of valid networks.  All other net-
    works are ignored.

    The -i flag, followed by the name of a network to which the host is con-
    nected (see networks(SFF)), overrides the default choice of the network
    addresses made by the program.  Each time the -i flag appears, that net-
    work name is added to a list of networks to ignore.  All other networks
    are used by the time daemon.

    _________________________________________________________________________
       NOTE  The -n and -i flags will be meaningless if used together.
    _________________________________________________________________________


    Network interfaces specified in /etc/if.ignore (see if.ignore(SFF)) will
    also be ignored by timed.

 Files

    /usr/adm/timed.log           tracing file for timed
    /usr/adm/timed.masterlog     log file for master timed
    /etc/if.ignore

 See also

    date(C), adjtime(SSC), gettimeofday(SSC), icmp(ADMP), rdate(ADMN),
    timedc(ADMN)