[c-nsp] NTP synchronization problems C2801

[Peter Rathlev]

On Wed, 2010-06-30 at 14:12 -0400, Rodney Dunn wrote:
> I'm not a NTP expert but I know there were some issues when it went to
> v4 regarding sync times, etc...
> 
> One of them was:
> 
> CSCte91471    NTP v4 takes several hours to sync when multiple servers
> are configured
> 
> From looking at the source code that fix doesn't appear to be in
> 15.0(1)M2.
> 
> You may want to try it with the next rebuild when it comes out.

That sounds just like it. I can see the 15.1(1)T also has the same bug,
so I guess there's no point in trying that one.

I've had an expect script run "show ntp status" every five minutes on
the two devices the last 5-6 hours, and if I extrapolate linearly
(R^2=0.76 though) the one running 15.0(1)M2 will be synchronized in
around 11 hours, from an offset of ~15 ms now.

The bug description says "... after few hours.", but this one will have
taken nearly 36 hours if the linear extrapolation is correct.

Tomorrow I will try to downgrade to 12.4(24)T3 to make sure it isn't
hardware related. The one running 12.4(24)T3 now has the past 5 hours
never exceeded 1 usec offset according to "show ntp status".

-- 
Peter