Path: utzoo!utgpu!water!watmath!clyde!rutgers!rochester!bbn!husc6!hao!ames!pasteur!ucbvax!ETN-WLV.EATON.COM!mcc
From: mcc@ETN-WLV.EATON.COM (Merton Campbell Crockett)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  Time synchronization and distribution plan
Message-ID: <8801251346.AA00458@etn-wlv.EATON.COM>
Date: 25 Jan 88 13:46:29 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 19

This discussion concerning time synchronization is interesting but I must be
missing the point somewhere.  For the dissemmination (sp) of message traffic
I fail to see why it is important to be synchronized within 1 or 2 milliseconds.

If time is important, such as for real-time ranging data, it would seem that
one should purchase a WWV receiver and interface which ain't all that expen-
sive.  The biggest problem will be clock "jitter" introduced by programmers
like myself who used the JFFO (DECSystem 10) instruction to decode the 48
bit BCD milliseconds since start of year for timestamping real-time data.
The cause of the "jitter" was a side effect of the JFFO instruction which
should have been found immediately except everyone was impressed by an
actual use for the JFFO instruction.

I digressed.  The solution is sites and subnets with "real-time" requirements
should have their own WWV receivers with only "nominal" pinging of the net to
verify the WWV receiver has not failed.  The rest can use their time of day
clocks since time isn't that important.

Merton Campbell Crockett