NTP Wrap Up

Unanswered Question
Apr 23rd, 2009

Hello all

I am desperately trying to trying to get a firm grip on the "show ntp ass."

figures being:

1) address

2) ref clock

3) st

4) when

5) poll

6) reach

7) delay

8) offset

9) disp

the 3 first numbers a self explaing.

nr 4 "when" is when the ntp last was heard from and poll is an increasing number, as far as i can tell trying to minimize NTP traffic (by incrementing the time between ntp packets). Is it possible to manually ask the (stratum 3)ntp server to poll the (stratum 2) server more often?

6 "reach" tells the number of Ntp replies.

and now i get lost.

What exactly is 7) delay 8) offset 9) disp


I thank you for your kindness in here so far and look forward to being smart enough to be of assistance in here.

/Jan Vejling CCNA (CCNP stud.) Denmark

I have this problem too.
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crow930us Fri, 04/24/2009 - 01:07

reach - The reach field is a circular bit buffer. It gives you the status of the last eight NTP messages .

delay - Round-trip delay to peer (in milliseconds).

offset - The offset field is the calculated offset (in milliseconds) between the client and server time.

disp - Current estimated dispersion of the peer, in seconds.

The last three deal with synchronization issues between the Master server and the client. Using this information you can tell how often messages are exchanged and what the estimated difference between the Master server and the client.

This documentation might also help: http://www.cisco.com/en/US/products/sw/iosswrel/ps1818/products_tech_note09186a008015bb3a.shtml


towli Sat, 04/25/2009 - 08:28

Thank you !

It might be because english is not my native language, but im still a bit confused: Round trip delay - would that be the time traffic takes from client to server and back again? Offset ? Is that a number the client has to add add to the recieved ntp time to comensate for jitter/ delay? Dispertion i have tried to look up in the danish-english dictionary but it still does not make sense to me. What is meant by dispertion?

I regret to try and lucrate on your kindness and i am embarrased that i dont understand it in first take.

Best regards

/Towli - Denmark


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