[ntp:questions] Re: NTP stratum problem
Richard B. Gilbert
rgilbert88 at comcast.net
Thu Aug 3 02:26:22 UTC 2006
> We have solris stations with ntp 4.2, act as a server and clients.
> These Solaris clients act as peers when the server is down. We have
> Vxworks machines polling these Solaris clients using VxWorks
> SntpTimeGet command.
> This setup works fine, except vxworks machines do not get ntp synced
> from solaris clients, when the server is down. ( When the solaris
> clients boot up - Ntp server is down). This problem does not happen if
> ntp server goes down once solaris clients get synced initially to the
> ntp server.
>>From TCPDUMP, we found that solris clients send stratum 0 to vxworks,
> when they do not get synced to the ntp server( initially), vxworks does
> not accept ntp messages with stratum set to Zero.
> Is there a way to set clients statum to non zero value, before clients
> get synced to the ntp server?
> Our config file is:
> tinker stepout 20
> server 10.2.10.70 prefer burst minpoll 4 maxpoll 6
> server 10.2.10.71 burst minpoll 4 maxpoll 6
You should probably be using "iburst" instead of "burst". "burst" is a
special purpose hack used, I believe, dialup internet connections.
"iburst" says to send the first eight queries at two second intervals.
It is used to get enough information to start synchronizing the clock in
about sixteen seconds instead of about 5 and a half minutes.
You also should probably NOT be specifying minpoll and maxpoll. Ntpd is
designed select an appropriate polling interval from the default range
of 6 to 10; it is rare to encounter a situation where something else
will work better.
I believe that "stratum 0" means "I am not synchronized" and clients are
quite correct in refusing to accept time from an unsynchronized system.
You can add lines like:
# Declare the local clock to be the clock of last resort.
# It will be used to serve time in the absence of any other.
server 127.127.1.0 # Local clock, unit 0
fudge 127.127.1.0 stratum 10
Setting the stratum to 10 when serving the unsynchronized local clock is
conventional and makes it unlikely that ANYONE will use such a server
unless there is nothing else available.
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