I've never taken the lab. I can give you my opinion. I suspect Cisco may vary
the Stratum of their NTP server on purpose by day/week, etc. Throwing students
who think they know the answer off. So the answer would depend on what Stratum
you getting.
Generally I don't think you won't need the master command unless they are
giving you a bad stratum >=10 which CallManager won't like.
Verify your hardware is close to current time via show clock.
Show ntp association detail <--------------is your master sane or insane, if
not why?
sc#show ntp assoc detail
172.10.64.254 configured, our_master, sane, valid, stratum 7
ref ID 172.100.64.10 , time D37CCC06.0A26BD47 (03:07:50.039 HKT Sat Jun 9 2012)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 0.00 msec, root disp 37.17, reach 377, sync dist 0.04
debug ntp to your buffer in background
From: ccie_voice-boun...@onlinestudylist.com
[mailto:ccie_voice-boun...@onlinestudylist.com] On Behalf Of Mann Chaddha
Sent: Friday, June 08, 2012 1:19 PM
To: ccie_voice@onlinestudylist.com
Subject: [OSL | CCIE_Voice] NTP Master Dilemma
Hi Experts
I am due for my next Lab attempt in 5 days time. I so far have never been able
to get marks for NTP section.
So I ask this question to the forum that if someone has ever scored 100% in the
Infra Section (without breaking the NDA of course) , can they lend some light
on this innocuous looking command, ntp master.
Here are some finding from my POD: [10.10.100.1 = PSTN RTR & 10.10.110.1=HQ RTR]
1. With NTP Master Command
R1:
ntp source Loopback0
ntp master 10
ntp server 10.10.100.1 source Loopback0
!
clock timezone PST -8
clock summer-time PDT recurring
R2:
ntp server 10.10.110.1
Show commands:
R1:
HQ-R1#sh ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0008 Hz, precision is 2**24
reference time is D37C1C18.AAB00668 (23:37:12.666 PDT Thu Jun 7 2012)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is -0.000003145 s/s
system poll interval is 64, last update was 384 sec ago.
HQ-R1#
HQ-R1#
HQ-R1#sh ntp ass
HQ-R1#sh ntp associations
address ref clock st when poll reach delay offset disp
x~127.127.1.1 .LOCL. 9 16 16 377 0.000 0.000 0.240
x~10.10.100.1 .LOCL. 1 50 64 377 0.000 13194.1 3.293
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
R2:
BR1-R2#sh ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 249.9990 Hz, precision is 2**24
reference time is 00000000.00000000 (16:00:00.000 PST Wed Dec 31 1899)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.01 msec, peer dispersion is 0.00 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000003885 s/s
system poll interval is 64, never updated.
BR1-R2#
BR1-R2#sh ntp ass
address ref clock st when poll reach delay offset disp
~10.10.110.1 73.78.73.84 16 55 64 300 0.000 1325166 944.35
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
CUCM:
admin:utils ntp status
ntpd (pid 6322) is running...
remote refid st t when poll reach delay offset jitter
==============================================================================
*127.127.1.0 LOCAL(0) 10 l 63 64 377 0.000 0.000 0.001
10.10.110.1 .INIT. 16 u 64 128 370 1.897 -2.990 1087693
synchronised to local net at stratum 11
time correct to within 12 ms
polling server every 512 s
Current time in UTC is : Fri Jun 8 06:22:22 UTC 2012
Current time in America/Los_Angeles is : Thu Jun 7 23:22:22 PDT 2012
------------------------------------------------------------------------------
Scenario 2: Without NTP Master Command.
------------------------------------------------------------------------------
R1:
ntp source Loopback0
ntp server 10.10.100.1 source Loopback0
!
clock timezone PST -8
clock summer-time PDT recurring
R2:
BR1-R2#r | s ntp
ntp server 10.10.110.1
Show Commands:
HQ-R1#sh ntp status
Clock is synchronized, stratum 2, reference is 10.10.100.1
nominal freq is 250.0000 Hz, actual freq is 250.0008 Hz, precision is 2**24
reference time is D37C21AB.D80D6753 (00:00:59.843 PDT Fri Jun 8 2012)
clock offset is -0.0078 msec, root delay is 0.00 msec
root dispersion is 0.01 msec, peer dispersion is 0.00 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is -0.000003182 s/s
system poll interval is 64, last update was 264 sec ago.
HQ-R1#
HQ-R1#sh ntp ass
address ref clock st when poll reach delay offset disp
*~10.10.100.1 .LOCL. 1 11 64 377 0.000 -7.866 2.813
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
HQ-R1#sh ntp ass d
10.10.100.1 configured, our_master, sane, valid, stratum 1
ref ID .LOCL., time D37C229E.73B36D17 (00:05:02.451 PDT Fri Jun 8 2012)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 0.00 msec, root disp 0.47, reach 377, sync dist 0.00
delay 0.00 msec, offset -7.8662 msec, dispersion 2.81
precision 2**24, version 4
org time D37C22AE.D47DF91B (00:05:18.830 PDT Fri Jun 8 2012)
rec time D37C22AE.D7653258 (00:05:18.841 PDT Fri Jun 8 2012)
xmt time D37C22AE.D6E2248F (00:05:18.839 PDT Fri Jun 8 2012)
filtdelay = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
filtoffset = -0.01 -0.00 -0.00 -0.00 -0.00 -0.00 -0.00 -0.00
filterror = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
minpoll = 6, maxpoll = 10
BR1-R2#sh ntp s
Clock is synchronized, stratum 3, reference is 10.10.110.1
nominal freq is 250.0000 Hz, actual freq is 249.9990 Hz, precision is 2**24
reference time is D37C2310.A8751D42 (00:06:56.658 PDT Fri Jun 8 2012)
clock offset is 0.0034 msec, root delay is 0.00 msec
root dispersion is 0.96 msec, peer dispersion is 0.93 msec
loopfilter state is 'CTRL' (Normal Controlled Loop), drift is 0.000003898 s/s
system poll interval is 64, last update was 7 sec ago.
BR1-R2#
BR1-R2#
BR1-R2#
BR1-R2#sh ntp ass
address ref clock st when poll reach delay offset disp
*~10.10.110.1 10.10.100.1 2 11 64 17 0.000 3.472 939.41
* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured
admin:utils ntp status
ntpd (pid 13103) is running...
remote refid st t when poll reach delay offset jitter
==============================================================================
127.127.1.0 LOCAL(0) 10 l 60 64 377 0.000 0.000 0.001
*10.10.110.1 10.10.100.1 2 u 57 64 377 1.718 1.677 5.437
synchronised to NTP server (10.10.110.1) at stratum 3
time correct to within 29 ms
polling server every 64 s
Current time in UTC is : Fri Jun 8 07:07:22 UTC 2012
Current time in America/Los_Angeles is : Fri Jun 8 00:07:22 PDT 2012
admin:
As soon as I apply NTP master command, it breaks my NTP Sync.
Am I missing something stupid in here. Please chime in.
Thanks
Mann
itevomcid
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