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Verify NTP master config

dino55088
Beginner
Beginner

I have a router BRI_2811_1 which is getting NTP from 10.66.41.201 and this is working.

When i then wish to make BRI_2811_1 the master for my local network, the internal clock on this router is coming up as "insane". Why is this is so? Eventually i would like all my switches to look to BRI_2811 as their NTP master.

 

BRI_2811_1#show run | i ntp|clock
clock timezone AEST 10 0
clock calendar-valid
ntp source Loopback0
ntp master 6
ntp server 10.66.41.201

 

BRI_2811_1#
BRI_2811_1#
BRI_2811_1#show ntp stat
BRI_2811_1#show ntp status 
Clock is synchronized, stratum 5, reference is 10.66.41.201  
nominal freq is 250.0000 Hz, actual freq is 249.9950 Hz, precision is 2**24
reference time is D8E4D87D.4E30DD39 (00:58:05.305 AEST Sat Apr 25 2015)
clock offset is -5.1655 msec, root delay is 57.61 msec
root dispersion is 326.92 msec, peer dispersion is 3.74 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000019698 s/s
system poll interval is 64, last update was 172 sec ago.
BRI_2811_1# 
BRI_2811_1#show ntp ass

  address         ref clock       st   when   poll reach  delay  offset   disp
 ~127.127.1.1     .LOCL.           5     13     16   377  0.000   0.000  0.243
*~10.66.41.201    10.66.9.16       4     48     64   377 22.535  -5.165  3.749
 * sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
BRI_2811_1#
BRI_2811_1#show ntp ass det
127.127.1.1 configured, insane, invalid, stratum 5
ref ID .LOCL., time D8E4D932.4915B594 (01:01:06.285 AEST Sat Apr 25 2015)
our mode active, peer mode passive, our poll intvl 16, peer poll intvl 16
root delay 0.00 msec, root disp 0.00, reach 377, sync dist 2.74
delay 0.00 msec, offset 0.0000 msec, dispersion 0.24
precision 2**24, version 4
org time D8E4D932.4915B594 (01:01:06.285 AEST Sat Apr 25 2015)
rec time D8E4D932.491675DE (01:01:06.285 AEST Sat Apr 25 2015)
xmt time D8E4D932.49152E3B (01:01:06.285 AEST Sat Apr 25 2015)
filtdelay =     0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filtoffset =    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filterror =     0.00    0.25    0.51    0.75    1.02    1.26    1.51    1.75
minpoll = 4, maxpoll = 4

10.66.41.201 configured, our_master, sane, valid, stratum 4
ref ID 43.66.9.16    , time D8E4D803.F3B64840 (00:56:03.952 AEST Sat Apr 25 2015)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 35.07 msec, root disp 317.04, reach 377, sync dist 386.52
delay 22.53 msec, offset -5.1655 msec, dispersion 3.74
precision 2**10, version 4
org time D8E4D8FE.4A7EFAA8 (01:00:14.291 AEST Sat Apr 25 2015)
rec time D8E4D8FE.4EB368F5 (01:00:14.307 AEST Sat Apr 25 2015)
xmt time D8E4D8FE.48E78643 (01:00:14.284 AEST Sat Apr 25 2015)
filtdelay =    22.64   22.77   22.53   22.65   22.82   22.97   22.57   22.82
filtoffset =   -5.10   -5.22   -5.16   -6.06   -5.33   -6.43   -6.73   -6.89
filterror =     0.97    1.96    2.91    3.85    4.83    5.80    6.75    7.72
minpoll = 6, maxpoll = 10

1 Accepted Solution

Accepted Solutions

The built in clock of a 2811 is a reasonably good clock for some purposes. But it is not a high precision clock when you start looking at the levels of precision that generally apply to NTP master clocks. That is the reason why it is categorized as insane.

 

If your router is learning NTP from an authoritative source (which seems to be the case from the output that you have posted) then it will serve NTP time to other devices in your network. You do not need to configure your router as master to be able for it to act as ntp server for other devices in your network. So is there a reason why you are trying to configure it as an NTP master?

 

HTH

 

Rick

HTH

Rick

View solution in original post

6 Replies 6

Krishnendu AR
Beginner
Beginner

Hello,

Are you still facing this issue?

Do you have any ntp access-group configured in the device?

Please share the output of 'sh clock detail' and 'sh ntp association detail' one more time.

Krishna

no access groups at all and router is next hop

 

HQ-3845#show clock det
10:40:01.020 AEST Sun Apr 26 2015
Time source is NTP
HQ-3845#sho ntp ass det
127.127.1.1 configured, insane, invalid, stratum 6
ref ID .LOCL., time D8E6B25A.72DE3D46 (10:39:54.448 AEST Sun Apr 26 2015)
our mode active, peer mode passive, our poll intvl 16, peer poll intvl 16
root delay 0.00 msec, root disp 0.00, reach 377, sync dist 2.96
delay 0.00 msec, offset 0.0000 msec, dispersion 0.24
precision 2**24, version 4
org time D8E6B25A.72DE3D46 (10:39:54.448 AEST Sun Apr 26 2015)
rec time D8E6B25A.72DE9CB0 (10:39:54.448 AEST Sun Apr 26 2015)
xmt time D8E6B25A.72DE0842 (10:39:54.448 AEST Sun Apr 26 2015)
filtdelay =     0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filtoffset =    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00
filterror =     0.00    0.25    0.49    0.73    0.99    1.26    1.53    1.78
minpoll = 4, maxpoll = 4

10.66.202.252 configured, our_master, sane, valid, stratum 4
ref ID 10.66.9.16    , time D8E6B1CB.E328A743 (10:37:31.887 AEST Sun Apr 26 2015)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 74.53 msec, root disp 189.16, reach 377, sync dist 306.79
delay 0.61 msec, offset -1.8279 msec, dispersion 4.73
precision 2**22, version 4
org time D8E6B23E.726564BD (10:39:26.446 AEST Sun Apr 26 2015)
rec time D8E6B23E.72FFC6BD (10:39:26.449 AEST Sun Apr 26 2015)
xmt time D8E6B23E.72CFC2A8 (10:39:26.448 AEST Sun Apr 26 2015)
filtdelay =     0.71    0.68    0.71    0.68    0.72    0.73    0.70    0.61
filtoffset =   -1.99   -1.97   -1.96   -1.97   -1.97   -1.97   -1.90   -1.82
filterror =     0.00    0.99    1.93    2.91    3.90    4.87    5.82    6.81
minpoll = 6, maxpoll = 10

Hi,

Try to use stratum "3" and then check.

The built in clock of a 2811 is a reasonably good clock for some purposes. But it is not a high precision clock when you start looking at the levels of precision that generally apply to NTP master clocks. That is the reason why it is categorized as insane.

 

If your router is learning NTP from an authoritative source (which seems to be the case from the output that you have posted) then it will serve NTP time to other devices in your network. You do not need to configure your router as master to be able for it to act as ntp server for other devices in your network. So is there a reason why you are trying to configure it as an NTP master?

 

HTH

 

Rick

HTH

Rick

hi Rick,

 

this is just a lab question I am answering . If I remove the command ntp master, it all looks synced and clean so I agree with you. The exercise asked to configure "ntp master" but maybe it is not the correct way of doing this  :) from this certain training institution.

If this is a lab question and if they specifically ask you to configure the router as NTP master then you should configure ntp master on your router. For real life and Generally Accepted Best Practice then I stand by my suggestions.

 

HTH

 

Rick

HTH

Rick
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