Hi Folks,
Can I put my 2 cents worth in?
>From: Bob Snyder <[EMAIL PROTECTED]>
>To: Andrew Benham <[EMAIL PROTECTED]>
>CC: [EMAIL PROTECTED]
>Subject: Re: Time bug
>Date: Tue, 30 Mar 1999 06:48:56 -0500 (EST)
>
>On Tue, 30 Mar 1999, Andrew Benham wrote:
>
>> I'm also not clear how NTP would cope in the situation where the MAC
layer
>> could delay the packet's transmission by many seconds.
>
>I know NTP is designed to cope with fair amounts of network delay; it's
>built into the protocol. Of course, I don't remember how, as I haven't
>looked at the protocol details in many years, but it's in there. Dunno
if
>it would be robust enough to handle the huge delays you can see on a
1200
>baud packet radio connection. (Look! I almost made the thread relavent
to
>the group! :-) )
>
In my practical experience (I ran GB7TVG, an IP based bbs for a few
years and had a 60khz MSF rx connected) the time really only survives
for a trip of no more than 3 hops using 1200bd.
In the Thames Valley (where my box was/is) there are quite a number of
IP bbs's working as a kind of routed network and the plan was to have
all of them fitted with a clock so that users would collect the time
from the nearest source ie, their upstream gateway.
We also played with 'cascaded sycronisation' where the servers without a
clock would collect the time from their upstream gateway and relay it
via rdate to the users.
This worked out very well for some 2 years until I moved house. Now that
service is being handled by Robin very well - Thanks Robin.
>NTP is designed to keep your time within milliseconds of it's source,
and
>can handle silly things like leap seconds, where a minute is declared
to
>have 61 seconds or 59 seconds to deal with minute changes in the
Earth's
>orbit. It can also deal with the loss of a clock and a "false ticker,"
a
>clock that reporting incorrect data, given enough alternate inputs.
>
>I use xntpd on my home system, with it treating it's own clock as a
>stratum 7 time device, and when my Internet connection's up, using two
>stratum 2 time sources on the net. I like it a lot, although I realize
>it's more than some people want.
>
>Bob N2KGO
>
Mark Phillips G7LTT/KC2ENI
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