[ntp:questions] Re: Reach isn't 377 on peered servers

David L. Mills mills at udel.edu
Wed Jan 11 21:41:59 UTC 2006


David.

Depending on phasing and poll interval, it might (and does) happen that 
during a poll interval one peer will see none, one or two polls from the 
other peer. That is normal and does not affect the synchronization 
function. Sometimes as the poll interval ramps up more than one interval 
may go by without an arriving packet. In the expected case where the 
peers are low in the stratum forest and the highest reliability is 
needed, it probably is a good idea to clamp the maxpoll to the default 
minpoll.

Dave

David J Taylor wrote:
> Edited NTPQ output:
> 
> C:\> ntpq -p bacchus
>      remote           refid      st t when poll reach   delay   offset 
> jitter
> =======================================================
> *oubliette.mctav .MSF.            1 u  141 1024  377   54.561   11.262 
> 1.568
> -hermes.djt.edi  195.66.241.3     3 u   35   64  357    1.103   12.116 
> 0.239
>  LOCAL(1)        .LOCL.          10 l   19   64  377    0.000    0.000 
> 0.008
> 
> C:\> ntpq -p hermes
>      remote           refid      st t when poll reach   delay   offset 
> jitter
> =======================================================
> +utserv.mcc.ac.u 130.88.200.98    3 u   65   64  377   26.178   -7.859 
> 0.950
> -bacchus.djt.edi 81.187.242.38    2 u   45   64   76    1.464  -12.020 
> 0.344
>  LOCAL(1)        .LOCL.          10 l   22   64  377    0.000    0.000 
> 0.002
> 
> On this peered pair of ntp servers, there are a number of Internet 
> servers, the two peered servers, and a local clock in case the Internet 
> connection goes down.
> 
> My question: although all the Internet servers and the local clock show 
> full connectivity (reach = 377), the peered servers do not (357 from 
> bacchus looking at hermes, and 76 from hermes looking at bacchus).  Why 
> isn't this 377?  These servers are on the same small LAN, and should have 
> 100% connectivity.
> 
> Hermes ntpd.conf includes:
> peer bacchus
> 
> Bacchus ntpd.conf includes:
> peer hermes iburst
> 
> (An accident that both don't have iburst!).
> 
> Thanks,
> David 
> 
> 




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