[ntp:questions] Remaining synced on an unsynchronised peer?

Michael Butow michael.buetow at comsoft.de
Tue Jan 12 02:47:50 UTC 2010


After reading the comments about synch loops etc., I am also getting a 
strong feeling this is basically stratum-related.

I never observed the hosts 'walking each other up' so far.
What I did observe is fluctuating reachability on them, alternating 
fairly regularly from one to the other. But the one which is synced 
remains so.

Assuming when both lose contact to the external world:
- one of them will lose all it's refclocks first
- its stratum will go up to higher than that of its peer
- therefore it syncs on its peer
- it's stratum goes up, now its peer will no longer sync to it

This would suggest that it's a matter of timing which one of them becomes 
synchronised on the other. I have to verify that - in my (very limited) 
trials it was always a particular one that became synchronised. That 
might well just have been chance.

However, I feel there's got to be a bug when an unsynchronised peer 
continues providing replies.




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