[cisco-voip] incorrect NTP stratum calculation?

[Lelio Fulgenzi]

I recently opened a case and the TAC engineer ran the "utils diagnose test" command on two of the subscribers. We saw the following output regarding NTP. Similar output on all subscribers. 

====================== 
test - ntp_stratum : Failed 
The reference NTP server is a stratum 5 clock. 
NTP servers with stratum 5 or worse clocks are deemed unreliable. 
Please consider using an NTP server with better stratum level. 

Please use OS Admin GUI to add/delete NTP servers. 
====================== 

This is very confusing, since we have synchronized the publisher to a stratum 3 NTP server, making the publisher a stratum 4. 

I don't think it's possible to synchronize the publisher to a stratum 2 since that would mean the publisher would have to talk to an upstream NTP server, this is not likely. 

some additional output: 

===== 
upstreamNTPserver>show ntp status 
Clock is synchronized, stratum 3, reference is <snip> 
nominal freq is 250.0000 Hz, actual freq is 249.9994 Hz, precision is 2**24 
reference time is D74EF2FD.DA2094A8 (13:50:53.852 EDT Fri Jun 20 2014) 
clock offset is -3.7102 msec, root delay is 13.73 msec 
root dispersion is 46.51 msec, peer dispersion is 18.67 msec 
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000002293 s/s 
system poll interval is 1024, last update was 1297 sec ago. 
===== 
on publisher 


admin:utils ntp status 
ntpd (pid 6808) is running... 

remote refid st t when poll reach delay offset jitter 
============================================================================== 
<snip> .LOCL. 10 l 38 64 377 0.000 0.000 0.001 
+<snip> <snip> 3 u 18 1024 377 0.647 4.618 0.043 
*<snip> <snip> 3 u 123 1024 377 0.726 -4.041 0.025 


synchronised to NTP server (upstreamNTPserver) at stratum 4 
time correct to within 86 ms 
polling server every 1024 s 

Current time in UTC is : Fri Jun 20 18:10:59 UTC 2014 
Current time in America/Toronto is : Fri Jun 20 14:10:59 EDT 2014 
===== 
on subscriber: 

admin:utils ntp status 
ntpd (pid 9136) is running... 

remote refid st t when poll reach delay offset jitter 
============================================================================== 
127.127.1.0 .LOCL. 10 l 54 64 377 0.000 0.000 0.001 
* < pub > <snip> 4 u 324 512 377 0.200 -0.289 0.022 


synchronised to NTP server (pub) at stratum 5 
time correct to within 98 ms 
polling server every 512 s 

Current time in UTC is : Fri Jun 20 18:19:08 UTC 2014 
Current time in America/Toronto is : Fri Jun 20 14:19:08 EDT 2014 
===== 

Software Version: 9.1.2.11900-12 


--- 
Lelio Fulgenzi, B.A. 
Senior Analyst, Network Infrastructure 
Computing and Communications Services (CCS) 
University of Guelph 

519‐824‐4120 Ext 56354 
lelio at uoguelph.ca 
www.uoguelph.ca/ccs 
Room 037, Animal Science and Nutrition Building 
Guelph, Ontario, N1G 2W1 

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