[ntp:questions] Client doesn't drop failed source

Danny Mayer mayer at ntp.org
Wed Jan 20 05:07:59 UTC 2010

Rick Jones wrote:
> David Woolley <david at ex.djwhome.demon.invalid> wrote:
>> For a start, if it dropped a source on the first missing reply it
>> would result in clock hopping, which is undesirable.  UDP is
>> unrliable, and you cannot rely on getting every query returned.
> In that sense then, even TCP is unreliable for it cannot guarantee
> getting every query returned.  What distinguishes TCP from UDP is that
> TCP will make multiple attempts to deliver the data and then signal
> the probable (but not certain) non-delivery of data.
> rick jones

More importantly, TCP requires a 3-way handshake before it can deliver
the packet, so there is setup time, delivery and tear-down time involved
as well just to deliver one small packet.


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