[ntp:questions] Client doesn't drop failed source

David Woolley david at ex.djwhome.demon.invalid
Wed Jan 20 08:04:29 UTC 2010

David Mills wrote:
> Not true. The dispersion does increase, but the server is valid until 
> the dispersion exceeds the select threshold, usually in four or five 
> more missed messages.

That's why I said the quality measures are invalidated, rather than the 
server is invalidated.  I probably should have said "effectively".  I 
guess that anti-clock hopping may reduce the effect.

I was really trying to correct my initial reading, that the only 
reachability check was reachability == 0.  There is also a reachability 
& 7 == 0 check, earlier in the code, which results in a sample with the 
maximum possible dispersion value being loaded.

I can't tell, quickly, what gets loaded when there are only one or two 
missed polls.  I'd always assumed that the filter slots tracked the 
rachability ones, but maybe not.

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