[ntp:questions] Help appreciated

Towli towli at oldboyz.dk
Tue May 12 20:41:08 UTC 2009


I think i may have the answer to my own question above...
I read somewhere that a man with 2 watches never know what time it is...

My switches sees the 2 external NTP-stratum1-servers as being closer to each 
other in time (due to their physical placement close to each other and 
relative to my core switches).
Therefore my core switches choose to trust the to more agreeing servers as 
opposed to my internal server, which is quite alone in its view on the time 
and whose time differs from the 2, due to the closer proximity /smaller 
delay.
Am i right in this assumption?

I removed 1 of the external NTP servers and now my internal DCF is used as 
prefered Ntp server.

Should i keep 1 of the external stratum-1-servers for backup or should i 
remove it all together? My Dcf77 sometimes looses connection to Frankfurt 
and when this happens it looses it stratum 1 value, and hence my core 
switches looses synch...


I hope i am not to unclear and would be happy for any advice.

/Towli Denmark


"Towli" <towli at oldboyz.dk> skrev i meddelelsen 
news:4a09d0e9$0$90267$14726298 at news.sunsite.dk...
> Hi all
>
> I found out that our Inet-Provider has stratum 1 servers available, and i 
> intended to use these together with our newly acquired DCF77 machinery.
> I configured our DFC77 and the 2 external stratum 1 servers on our 2 core 
> switches to deliver Ntp to the rest of the network...
> Unfortunately (?) my switches seem to prefer these external time sources 
> as opposed to our own internal DCF77 Furthermore i can se (from output 
> below) that our internal DCF77 is listed as "invalid" ? ? ? Why is that?
> I have not yet set up our backup DCF77. When i do - should i loose the 2 
> external sources and use solely internal NTPservers or what would your 
> recommendations  / best practice be, based on the output below ?
>
> Any advice is highly appreciated as i am on thin ice here, and it is an 
> important task to implement NTP correctly on out network.
>
> Output: (for "anonymous" purposes in regards to my job i have marked the 
> external ip's with xxx)
>
>
> /Towli - Denmark
>
>
> #sh ntp ass de
> 193.xxx.xxx.xxx configured, our_master, sane, valid, stratum 1
> ref ID .GPS., time CDB44C38.435EEBEB (21:27:52.263 CEST Tue May 12 2009)
> our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
> root delay 0.00 msec, root disp 1.69, reach 377, sync dist 9.247
> delay 6.13 msec, offset 4.1194 msec, dispersion 4.30
> precision 2**18, version 3
> org time CDB44C68.7CC60B4F (21:28:40.487 CEST Tue May 12 2009)
> rcv time CDB44C68.7C8118AB (21:28:40.486 CEST Tue May 12 2009)
> xmt time CDB44C68.7AEB32B4 (21:28:40.480 CEST Tue May 12 2009)
> filtdelay =     6.13    6.12    5.57    8.21    5.10    6.33    5.98 
> 5.05
> filtoffset =    4.12    6.02    8.18    9.58   13.80   16.39   19.32 
> 22.59
> filterror =     0.02    0.99    1.97    2.94    3.92    4.90    6.64 
> 8.59
>
> 193.zzz.zzz.zzz configured, selected, sane, valid, stratum 1
> ref ID .GPS., time CDB44C3C.894CBE10 (21:27:56.536 CEST Tue May 12 2009)
> our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
> root delay 0.00 msec, root disp 1.80, reach 377, sync dist 7.889
> delay 5.43 msec, offset 4.2101 msec, dispersion 3.37
> precision 2**18, version 3
> org time CDB44C74.7DD78E42 (21:28:52.491 CEST Tue May 12 2009)
> rcv time CDB44C74.7D760EA9 (21:28:52.490 CEST Tue May 12 2009)
> xmt time CDB44C74.7C0F49F3 (21:28:52.484 CEST Tue May 12 2009)
> filtdelay =     5.43    6.73    5.94    5.89    6.13    4.82    5.07 
> 5.49
> filtoffset =    4.21    5.25    7.64   10.08   12.67   16.30   17.74 
> 20.33
> filterror =     0.02    0.99    1.97    2.94    3.92    4.90    5.87 
> 7.83
>
> 10.200.138.20 configured, sane, invalid, stratum 1
> ref ID .DCF., time CDB44934.00000000 (21:15:00.000 CEST Tue May 12 2009)
> our mode client, peer mode server, our poll intvl 1024, peer poll intvl 
> 1024
> root delay 0.00 msec, root disp 0.00, reach 377, sync dist 21.103
> delay 3.27 msec, offset -11.4426 msec, dispersion 7.02
> precision 2**6, version 3 <------------------------- what does this 
> precission indicate ? Better or worse than 2**18 ?
> org time CDB44944.71A00000 (21:15:16.443 CEST Tue May 12 2009)
> rcv time CDB44944.74F8FC00 (21:15:16.456 CEST Tue May 12 2009)
> xmt time CDB44944.7422D23A (21:15:16.453 CEST Tue May 12 2009)
> filtdelay =     3.27    1.57    2.12    1.37    1.34    1.43    1.34 
> 2.64
> filtoffset =  -11.44   -5.19   -5.52   -1.00   -2.57   -1.61   -1.85 
> 0.17
> filterror =     0.02    7.83   14.65   22.46   30.27   38.09   42.01 
> 49.82 




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