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Difference between SNTP client and NTP client

Hi, 
From the RFC for SNTPv3 and NTPv3 I dont find any differences in packet structure and client implementation.

Does it mean we can use one client implementation interchangeably with either a NTP or SNTP server assuming client operates in same mode in both cases?

There is one difference with authentication field but that is optional.

Regards 
Nataraja 
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Natraj
11/16/2016 7:20:53 AM
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On 16/11/16 07:20, Natraj Kn wrote:
> From the RFC for SNTPv3 and NTPv3 I dont find any differences in packet structure and client implementation.
>

Version 3 is obsolete, except for Microsoft.

> Does it mean we can use one client implementation interchangeably with either a NTP or SNTP server assuming client operates in same mode in both cases?

Yes, but the system as a whole will be SNTP, not NTP.
>
> There is one difference with authentication field but that is optional.

The key differences for the client are that SNTP clients are always 
stratum 16 and they need not implement the filtering logic used by an 
NTP client.


0
David
11/16/2016 9:33:41 AM
Natraj Kn wrote:
> Hi, 
> From the RFC for SNTPv3 and NTPv3 I dont find any differences in packet structure and client implementation.
> 
> Does it mean we can use one client implementation interchangeably with either a NTP or SNTP server assuming client operates in same mode in both cases?
> 
> There is one difference with authentication field but that is optional.

Assuming an NTP server provides sufficient accuracy and precision, the
resulting accuracy for a client depends (beside the network
characteristics) mostly on the client properties:

- The client hardware
- The client OS
- The implementation of the NTP software on the client

A good client like the ntpd reference implementation tries to

- Filter out network jitter
- Determine the drift of the own system time
- Apply a system time adjustment slowly and smoothly in a way that

- The system clock drift is minimized
- The system time offset is minimized

On the other hand a Simple NTP client may just poll an NTP server once
and apply a correction or even step the time based on a single polling
result.

There can be lots of variations of enhanced NTP client software like the
former and simple implementations like the latter, which may or may not
conform to one of the RFCs.

I've put some information together here:
https://www.meinbergglobal.com/download/burnicki/time_synchronization_accuracy_with_ntp.pdf


Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany
0
Martin
11/16/2016 12:18:28 PM
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