[ntp:questions] monitoring symmetric peers

Kostas Magkos kmag at islab.demokritos.gr
Tue Jul 13 09:22:32 UTC 2010


Dear David,

First of all, thank you for your reply!

> Your symmetric peers have the same upstream system peer, so by rule
> they are not going to believe each other unless one of them switches
> to a different upstream source. 
Well, because I anticipated this one, I've configured the servers to use
a different set of stratum 1 peers.
> Even if they have differerent upstream sources, one of them will not
> beleive the other, since that would create a loop.
So, what you mean is that they could never be sys.peers, right?

But what about symmetrical peering? I cannot verify this association.
For example, when I query the servers for their peers with ntpq (ntpq
-p) they give out a 'u' (in the 't' column) for each other. Shouldn't
there be a 's' code, as in symmetric peer?

Below, some sample output, where 172.16.1.11 and 172.16.1.12 are my servers.

$ ntpq -pn ntp2
     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
-172.16.1.11    193.79.237.14    2 u  510 1024  377    0.001    0.086 
28.478
+193.0.0.228     .GPS.            1 u  207 1024  377   55.048  -24.032 
28.488
-193.10.7.246    .PPS.            1 u  722 1024  377   75.233   10.813 
17.102
*131.130.251.107 .PPS.            1 u  727 1024  377   33.881  -16.762 
18.901
-193.204.114.233 .CTD.            1 u  915 1024  377   50.021    1.255  
2.851
-213.10.47.241   .GPS.            1 u  203 1024  377   81.600    7.437 
27.455
+129.6.15.28     .ACTS.           1 u  726 1024  377  144.306  -18.561 
19.022

$ ntpq -pn ntp1
     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
-172.16.1.12    213.10.47.241    2 u  795 1024  376    0.001  -16.716  
0.134
-194.177.210.214 .GPS.            1 u    1 1024  377    1.403  -30.231
437.853
*62.119.40.98    .PPS.            1 u  985 1024  377   97.694    3.408 
11.246
-193.171.23.163  .PPS.            1 u  891 1024  377   33.508    7.661  
8.615
-193.204.114.232 .CTD.            1 u  398 1024  377   49.940   15.822 
25.070
-193.79.237.14   .PPS.            1 u  274 1024  377   56.543  -32.257 
28.882
+204.152.184.72  .GPS.            1 u  911 1024  377  207.045   -3.783  
3.356
+129.6.15.29     .ACTS.           1 u  365 1024  377  149.932   -5.298 
25.786


Let me rephrase my question: Were the two servers symmetric peers, what
would I see in the association and peer listing?





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