[ntp:questions] NTP - orphan mode with SAME stratum ("tos orphan 6") FAIL to sync.

David Woolley david at ex.djwhome.demon.co.uk.invalid
Wed Apr 8 07:34:03 UTC 2009

sheikdawoodrajali at gmail.com wrote:
> On Apr 6, 7:05 pm, Steve Kostecke <koste... at ntp.org> wrote:
>> On 2009-04-06, sheikdawoodraj... at gmail.com <sheikdawoodraj... at gmail.com> wrote:
>> [snip: a 27 line block of text]
>>> Yes, that's what I'm experimenting now.
>> What are you experimenting with?
>>> I beleive the Orphan Broadcast Mesh will work when none of the
>>> systems configured with external time servers at all.
>> Why don't you test it? I have.
>>> I saw it working time-sync'ed after adding shim value "tos mindist
>>> 0.010" for correctness interval.
>> I've conducted extensive testing with Orphan Mode and never had to add
>> a tos mindist command.
>>> I beleive the "time island" concept will work fine
>> The nodes will all be chasing whichever clock is chosen as the master.
>>> and time-sync will happen regardless of ANY time set in ALL the nodes
>>> running NTP service.
>> Why would you be changing the clock on systems which are running ntpd?
>>> Is there any restrictions in time difference on a time island (30
>>> minutes or less)??
>> Restrictions in the time island between what things?
>>> Here is the "ntp.conf" file on ALL the systems (7 nos):
>>> ------------------------------------------------------------------
>>> driftfile "C:\Program Files\NTP\etc\ntpd.drift"
>>> keys "C:\Program Files\NTP\etc\ntpd.keys"
>>> trustedkey 1
>>> # Any clock offset will be accepted
>>> tinker panic 0
>>> #shim added to the correctness interval
>>> tos mindist 0.010
>>> # We participate as orphans to auto-find a Time Server
>>> tos orphan 6
>>> # Default restrict all
>>> restrict default ignore
>>> # Allow local host for utilities like ntpq
>>> restrict mask
>>> # Allow communication over primary
>>> restrict <primary IP> mask nomodify notrap
>>> # Allow communication over secondary
>>> restrict <secondary IP> mask nomodify notrap
>>> broadcastclient
>>> broadcast xx.yy.255.255 key 1
>>> broadcast xx.zz.255.255 key 1
>> What is the purpose of broadcasting on two different addresses?
>> --
>> Steve Kostecke <koste... at ntp.org>
>> NTP Public Services Project -http://support.ntp.org/- Hide quoted text -
>> - Show quoted text -
> [Steve] Why would you be changing the clock on systems which are
> running ntpd?
> Our test plan is to verify if the time-sync happens fine after
> reducing (approx 30 minutes)
> on a system in a "orphan" group.

NTP is designed on the basis that time behaves like time, at least as 
obtained from a crystal oscillator.  Time doesn't experience phase 
discontinuities of 30 minutes, so, although ntpd should eventually cope 
(at least non-orphan mode), you are operating outside the specification.

In the recommeded configuration, ntpd will abort if the majority of its 
sources suddenly change by that amount, although I've noticed you used 
tinker (and hence taken ntpd out of any guaranteed configuration) to 
override that.

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