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

Magnus Danielson magnus at rubidium.dyndns.org
Wed Feb 27 22:02:49 EST 2013


On 02/12/2013 08:19 PM, Mike S wrote:
> On 2/10/2013 6:04 PM, Magnus Danielson wrote:
>> You should read "TCP/IP" as "Internet Protocols" (notice plural form
>> here). It points to the stack of protocols,
>
> Actually, no. IP is Internet Protocol, singular, and is the L3 (mostly -
> IP predates the ISO/OSI model layers, so IP suite protocols don't map
> exactly) protocol upon which both TCP and UDP are built. It's defined by
> RFC 791.
>
> TCP/IP, simply because those are the most commonly used protocols in the
> suite.

In the context it was written, it used the well spread misnomer of the 
suite to be referred to TCP/IP. The protocol suite was many times 
referred to as TCP/IP even if UDP was used for the particular transport 
over IP. It is a confusing thing and people have become better at using 
the correct terms, so in the context that "NTP used TCP/IP" is means 
that NTP uses the Internet Protocol suite, not TCP over IP.

As I recall NTPv3 in RFC 1305, it only specifies UDP over IP.

The ISO/OSI model stuff is a bad fit for the IP-stack, but it got stuck 
and fits the reality really bad. It's usage is discouraged.

Cheers,
Magnus


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