[ntp:questions] Re: on calculi for delay & offset

Christopher J. Holland msnews at microsoft.com
Sun Aug 3 23:16:15 UTC 2003


Hi,

> i was thinking about this: an SNTP client sends a packet with all bytes
set
> to 0 but the first one, so every timestamp is set to 0.
You send the Originate Timestamp and the 3 other 64 bit timestamps are 00's.

>Now, when the client comes to calculate the delay and the offset it needs
the Originate
> Timestamp (which, it's known, is copied by the server from the packet
> recieve) but, hey, where is it? It has no valid Originate Timestamp...
Yes it does.
The Originate TimeStamp was sent by you in the First Packet.
My guess is that the server just copies it and sends it back to you.
Maybe they plan on doing something with it?

> The conclusion is: if the client wants to calculate the delay and the
offset
> it has to send a packet with a valid timestamp and it doesn't want those
> results it can send a packet fill with 0 except the first. Am i right?
Well, you should go ahead and send the Timestamp, since that is what the
protocol calls for.

See if this help.
http://24.25.205.51/Project_TCPIP/Project_NTP/Project_NTP.htm
I'm close to figuring the protocol out.

HTH,
"Morpheus" <spam at world.com> wrote in message
news:UIdXa.15206$an6.551919 at news1.tin.it...
> Hi,
> i was thinking about this: an SNTP client sends a packet with all bytes
set
> to 0 but the first one, so every timestamp is set to 0. Now, when the
> client comes to calculate the delay and the offset it needs the Originate
> Timestamp (which, it's known, is copied by the server from the packet
> recieve) but, hey, where is it? It has no valid Originate Timestamp...
> The conclusion is: if the client wants to calculate the delay and the
offset
> it has to send a packet with a valid timestamp and it doesn't want those
> results it can send a packet fill with 0 except the first. Am i right?
>
> thanks again





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