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Community Member

ntp question

Hello community,

my company's network has two ntp masters. When issuing the command show ntp associations one 65xx gives me the output:

Sw-MK-C6509-R-IS-MHX-A1#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp
~127.127.7.1      127.127.7.1       7     9    64  377     0.0    0.00     0.0
~129.132.98.11    0.0.0.0          16     -  1024    0     0.0    0.00  16000.
+~193.93.167.241   193.93.167.161    2   122   256  377     2.5   -1.24     0.2
*~130.149.17.8     .PPS.             1    41   256  377    58.4   -0.59     0.6
~193.218.254.1    0.0.0.0          16     -  1024    0     0.0    0.00  16000.
* master (synced), # master (unsynced), + selected, - candidate, ~ configured


and the other:

Sw-KK-C6509-R4A1#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp
*~127.127.7.1      127.127.7.1       7     0    64  377     0.0    0.00     0.0
~130.149.17.8     .PPS.             1  104d    64    0    64.5    0.22  16000.
~193.218.254.1    0.0.0.0          16  169d  1024    0     0.0    0.00  16000.
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

I read in the following link https://supportforums.cisco.com/docs/DOC-1263, that:

"What is the address 127.127.7.1?

This is the reference clock address for the Cisco router when the router acts as a NTP master. If the router has not been synchronized with any NTP server, the router will use this address as the Reference ID."

Does this mean that this 65xx is not synchronized and that any device referencing it as its ntp server will too not be synched?

The thing is that I have encountered problems with the synch of many network devices, and I was wondering if this is the cause.

Thanks in advance.

12 REPLIES
Hall of Fame Super Blue

Re: ntp question

Does this mean that this 65xx is not synchronized and that any device referencing it as its ntp server will too not be synched?

It is sync to 130.149.17.8.  Look at the "*" symbol.

Purple

Re: ntp question

hi,

do a sh ntp status and sh ntp assoc detail, this should give more info about the issue.

And also  sh clock on both devices.

Regards.

Don't forget to rate helpful posts.
Community Member

Re: ntp question

Hi,

According to the output:

Sw-KK-C6509-R4A1#sh ntp associations

      address         ref clock     st  when  poll reach  delay  offset    disp
*~127.127.7.1      127.127.7.1       7     0    64  377     0.0    0.00     0.0
~130.149.17.8     .PPS.             1  104d    64    0    64.5    0.22  16000.
~193.218.254.1    0.0.0.0          16  169d  1024    0     0.0    0.00  16000.
* master (synced), # master (unsynced), + selected, - candidate, ~ configured

the desired source (130.149.17.8 - .PPS.) is not synchronised on this 6500.

You can tell as the reach is 0, and dispersement is 16000.

I agree with the previous poster, using the show ntp status would also show this.

I would troubleshoot why you are not synchronising with this NTP source - is there NTP authentication?  Firewall blocking ports?  Routing problems?

Regards, Ash.

Community Member

Re: ntp question

I do not have a problem with the 65xx named Sw-MK-C6509-R-IS-MHX-A1. This seems fine as can be seen from the output:

Sw-MK-C6509-R-IS-MHX-A1#sh ntp associations de
127.127.7.1 configured, insane, invalid, stratum 7
ref ID 127.127.7.1, time D0978873.1F473CDB (14:49:55.122 EET Wed Nov 24 2010)
our mode active, peer mode passive, our poll intvl 64, peer poll intvl 64
root delay 0.00 msec, root disp 0.00, reach 377, sync dist 0.015
delay 0.00 msec, offset 0.0000 msec, dispersion 0.02
precision 2**18, version 3
org time D0978873.1F473CDB (14:49:55.122 EET Wed Nov 24 2010)
rcv time D0978873.1F473CDB (14:49:55.122 EET Wed Nov 24 2010)
xmt time D0978873.1F46E00C (14:49:55.122 EET Wed Nov 24 2010)
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 =     0.02    0.99    1.97    2.94    3.92    4.90    5.87    6.85
Reference clock status:  Running normally
Timecode:

129.132.98.11 configured, insane, invalid, unsynced, stratum 16
ref ID 0.0.0.0, time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
our mode client, peer mode unspec, our poll intvl 1024, peer poll intvl 1024
root delay 0.00 msec, root disp 0.00, reach 0, sync dist 69899.368
delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00
precision 2**5, version 3
org time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
rcv time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
xmt time D09786E8.1EB1A1DB (14:43:20.119 EET Wed Nov 24 2010)
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 =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

193.93.167.241 configured, selected, sane, valid, stratum 2
ref ID 193.93.167.161, time D097874D.D456F065 (14:45:01.829 EET Wed Nov 24 2010)
our mode client, peer mode server, our poll intvl 512, peer poll intvl 512
root delay 0.61 msec, root disp 6.79, reach 377, sync dist 14.511
delay 7.46 msec, offset -1.2000 msec, dispersion 0.60
precision 2**20, version 3
org time D09787A8.1FA4716A (14:46:32.123 EET Wed Nov 24 2010)
rcv time D09787A8.20E7FC6F (14:46:32.128 EET Wed Nov 24 2010)
xmt time D09787A8.1EFB5ED3 (14:46:32.121 EET Wed Nov 24 2010)
filtdelay =     7.46    3.63    2.37    2.44    3.85    2.35    2.91    2.55
filtoffset =   -1.20   -0.80   -0.32   -0.33   -0.96   -0.32   -0.10   -0.58
filterror =     0.02    7.83   15.64   23.45   27.36   29.88   33.78   37.69

130.149.17.8 configured, our_master, sane, valid, stratum 1
ref ID .PPS., time D09787E2.BDD72BBE (14:47:30.741 EET Wed Nov 24 2010)
our mode client, peer mode server, our poll intvl 512, peer poll intvl 512
root delay 0.00 msec, root disp 0.46, reach 373, sync dist 34.897
delay 62.35 msec, offset -1.5563 msec, dispersion 1.30
precision 2**27, version 3
org time D09787F2.26B50305 (14:47:46.151 EET Wed Nov 24 2010)
rcv time D09787F2.2F164969 (14:47:46.183 EET Wed Nov 24 2010)
xmt time D09787F2.1F17DD48 (14:47:46.121 EET Wed Nov 24 2010)
filtdelay =    62.35   59.20   84.70   58.41   58.61   58.29   60.47   57.92
filtoffset =   -1.56   -0.49   -0.01   -0.06    0.28    0.24   -0.85    0.20
filterror =     0.02    7.83   23.45   27.36   30.09   34.00   37.90   41.81

193.218.254.1 configured, insane, invalid, unsynced, stratum 16
ref ID 0.0.0.0, time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
our mode client, peer mode unspec, our poll intvl 1024, peer poll intvl 1024
root delay 0.00 msec, root disp 0.00, reach 0, sync dist 69899.368
delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00
precision 2**5, version 3
org time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
rcv time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
xmt time D09786E8.1EB86743 (14:43:20.120 EET Wed Nov 24 2010)
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 =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

Sw-MK-C6509-R-IS-MHX-A1#sh ntp status
Clock is synchronized, stratum 2, reference is 130.149.17.8

nominal freq is 250.0000 Hz, actual freq is 249.9985 Hz, precision is 2**18
reference time is D09787F2.2F164969 (14:47:46.183 EET Wed Nov 24 2010)
clock offset is -1.5563 msec, root delay is 62.35 msec
root dispersion is 3.31 msec, peer dispersion is 1.30 msec

The problem is with Sw-KK-C6509-R4A1as can be seen below:
Sw-KK-C6509-R4A1#sh ntp status
Clock is synchronized, stratum 8, reference is 127.127.7.1
nominal freq is 250.0000 Hz, actual freq is 249.9994 Hz, precision is 2**18
reference time is D097874F.550A2DE0 (14:45:03.332 EET Wed Nov 24 2010)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.02 msec, peer dispersion is 0.02 msec

Sw-KK-C6509-R4A1#sh ntp associations detail
127.127.7.1 configured, our_master, sane, valid, stratum 7
ref ID 127.127.7.1, time D097874F.550A2DE0 (14:45:03.332 EET Wed Nov 24 2010)
our mode active, peer mode passive, our poll intvl 64, peer poll intvl 64
root delay 0.00 msec, root disp 0.00, reach 377, sync dist 0.015
delay 0.00 msec, offset 0.0000 msec, dispersion 0.02
precision 2**18, version 3
org time D097874F.550A2DE0 (14:45:03.332 EET Wed Nov 24 2010)
rcv time D097874F.550A2DE0 (14:45:03.332 EET Wed Nov 24 2010)
xmt time D097874F.5509DC55 (14:45:03.332 EET Wed Nov 24 2010)
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 =     0.02    0.99    1.97    2.94    3.92    4.90    5.87    6.85
Reference clock status:  Running normally
Timecode:

130.149.17.8 configured, insane, invalid, stratum 1
ref ID .PPS., time D00D3BD3.BE1DC81A (18:10:11.742 EET2 Wed Aug 11 2010)
our mode client, peer mode server, our poll intvl 64, peer poll intvl 128
root delay 0.00 msec, root disp 0.24, reach 0, sync dist 140077.560
delay 64.51 msec, offset 0.2156 msec, dispersion 16000.00
precision 2**27, version 3
org time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
rcv time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
xmt time D097872D.54FF49A2 (14:44:29.332 EET Wed Nov 24 2010)
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 =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

193.218.254.1 configured, insane, invalid, unsynced, stratum 16
ref ID 0.0.0.0, time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
our mode client, peer mode unspec, our poll intvl 1024, peer poll intvl 1024
root delay 0.00 msec, root disp 0.00, reach 0, sync dist 243947.250
delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00
precision 2**5, version 3
org time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
rcv time 00000000.00000000 (02:00:00.000 EET Mon Jan 1 1900)
xmt time D0978757.5506F3B1 (14:45:11.332 EET Wed Nov 24 2010)
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 =  16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

What could be the problem and how do I troubleshoot it???

Purple

Re: ntp question

Hi,

what is the show clock output on each switch and on the ntp master?

regards.

Don't forget to rate helpful posts.
Community Member

Re: ntp question

The time is correct on both masters:


Sw-MK-C6509-R-IS-MHX-A1#sh clock
15:06:58.640 EET Wed Nov 24 2010

Sw-KK-C6509-R4A1#sh clock
15:06:34.587 EET Wed Nov 24 2010

Purple

Re: ntp question

Oups these are masters both of them ! ok so they should be both synced with the ntp server with a lower stratum  which is not the case.

Can you give output of  show run | section ntp on both switches.

Don't forget to rate helpful posts.
Community Member

Re: ntp question


The output is as follows:

1) For the working Master (Sw-MK-C6509-R-IS-MHX-A1):

ntp source Loopback1
ntp master
ntp server 129.132.98.11
ntp server 193.93.167.241
ntp server 130.149.17.8 prefer
ntp server 193.218.254.1

2) For the "problematic" Master (Sw-KK-C6509-R4A1):

ntp source Loopback1
ntp master
ntp server 130.149.17.8 prefer
ntp server 193.218.254.1

I must state that the two devices are in different locations, connected through metro-ethernet and the connection to the internet is in the working masters' site (if this info is by any means relevant).

Thanks in advance for your help.

Purple

Re: ntp question

Hi,

Can Sw-KK-C6509-R4A1 ping  130.149.17.8 from Loopback1  ?

Regards.

Don't forget to rate helpful posts.
Community Member

Re: ntp question

No, but neither can Sw-MK-C6509-R-IS-MHX-A1. I must check with the security guys, so that they can check the checkpoint.

I'll get back to you, when I have an answer.

Thnx

Community Member

Re: ntp question

Hello community again,

The problem seems to have corrected itself! The "problematic" 65xx has the correct ntp master:

Sw-KK-C6509-R4A1#sh ntp status
Clock is synchronized, stratum 2, reference is 130.149.17.8
nominal freq is 250.0000 Hz, actual freq is 249.9992 Hz, precision is 2**18
reference time is D0A75CA2.DDCEA106 (14:59:14.866 EET Mon Dec 6 2010)
clock offset is -0.9114 msec, root delay is 64.80 msec
root dispersion is 6.23 msec, peer dispersion is 4.96 msec


Unfortunately since I was out of the office for the past week, I don't know what might have happened. The network itself is quite stable and nothing as far as I know has changed in our infrastructure.

I really hate it when things correct themselves without us knowing what the cause was...

Thank you for your help.

Hall of Fame Super Gold

Re: ntp question

Katerina

Thanks for posting back to the forum and updating the status of this issue. I agree with you that it is frustrating when things fix themselves and we can not get an understanding of what the underlying issue was or what happened that fixed it.

I have one observation to offer about the possibility that the problem was connectivity to the configured NTP server. From this output from a previous post we can see that your switch knows the reference clock from the configured NTP server. I believe that this shows that there was at least some level of communication going on.

130.149.17.8 configured, insane, invalid, stratum 1
ref ID .PPS., time D00D3BD3.BE1DC81A (18:10:11.742 EET2 Wed Aug 11 2010)

But I do wonder about the time given in the message. Was this output really from Aug 11 2010? It certainly does not agree with the output from the working switch. I do not know what caused it, but I believe that this was the reason that your problem switch could not sync to the configured NTP server.

HTH

Rick

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