[time-nuts] Possibly off topic - Jitter on Ethernet over power adapters

Magnus Danielson magnus at rubidium.dyndns.org
Sun Feb 10 18:04:40 EST 2013


Hi Bill,

On 02/10/2013 07:44 PM, Bill Hawkins wrote:
> P.S. The Meinberg article at their site says that NTP and SNTP both use
> TCP/IP. I know that SNTP uses UDP/IP, so perhaps they are confused. TCP
> (Transmission Control Protocol) requires a request/confirm / indication/
> /response handshake using those protocol primitives. UDP simply sends a
> message in the hope that it will get to the receiver. When it works, you
> get good time data, but you get garbage when it doesn't. The TCP handshake
> would be coumterproductive for NTP.

You should read "TCP/IP" as "Internet Protocols" (notice plural form 
here). It points to the stack of protocols, which includes stuff like 
ARP etc without it also being mentioned. It is common for dual uses like 
that. UDP comes in by association in the TCP/IP suite of protocols.

NTP and SNTP uses UDP.

Cheers,
Magnus


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