tcp-ip@ucbvax.ARPA (05/29/85)
From: mills@dcn6.arpa Folks, The evening thunderstorms tonight glitched the power at both our primary NBS radio WWVB clock receiver at Vienna, VA, and secondary NBS radio WWV clock receiver 25 miles away at University Park, MD, leaving our fuzzballs unfit to set your watches to. Even the tertiary GOES satellite clock receiver at Dearborn, MI, was unreachable because of traffic congestion due in part to braindamaged host BBN-META trying to set its watch every five minutes around the clock. Unfortunately, the fuzzies revert to j-random time on 1 January 1985 without comfort of at least one reachable radio fix, which apparently made a lot of hosts nervous. A veritable onslaught was observed here as several clock watchers stomped on first one fuzzy and then another when this occured. I bet a lot of files on IBM PCs up at MIT will have strange timestamps as a result. WWVB and WWV radio clock receivers get tummyaches in Summer when ambient static levels are at their highest. After the glitch tonight, both the primary and secondary clocks wandered for several hours before eventually synchronizing on their respective transmitters near Boulder, CO. I tried to lessen the pain by locking the DCNet swamp to an ISI host, only to discover that host was locking to the DCNet swamp! Meanwhile, the local power grid was sloshing to-and-fro milliseconds and glitzing the tracking filters used to synchronize the DCNet hosts themselves in the absence of the normal quartz-stabilized reference. All this could have been avoided if we had a UPS at either the primary or secondary site. While I am sorry for all those braindamaged timestamps, I again would like to request of all our timetelling friends: please resist the urge to set your watches from our fuzzballs with TCP. This causes much grief due to limited connection resources - recently seven different hosts were observed simultaneously beating on the DCN1 server at the same time! Puhleeze use UDP instead of TCP. Also, again note DCN1 is the primary source of accurate time - all the other fuzzlings can provide time only at degraded accuracy. Finally, will someone please toss a bomb on BBN-META? Dave -------
tcp-ip@ucbvax.ARPA (05/30/85)
From: CERF@USC-ISI.ARPA Dave, can you reject time calls coming in via TCP or is the mere act of rejection a resource-consuming activity which cannot be borne? Vint
tcp-ip@ucbvax.ARPA (05/31/85)
From: Murray.pa@Xerox.ARPA We now have a UDP time server on Xerox.ARPA. This machine gets it's time from the local Ethernet. The time servers out there are hooked up to the GOES satellite. Usually the clocks around here are less than 30 seconds off. Occasionally, they get confused. I've lost contact with DCN1, so I can't double check right now, but we normally agree to within a few seconds.
tcp-ip@ucbvax.ARPA (05/31/85)
From: mills@dcn6 Murray, I dunno how you lost contact with DCN1, since you have to go through there to get to this host. If your clock reference is anywhere close to GOES, you should be a lot closer than "a few seconds." Mumble a TCP connection to DCN1 on port 15 and look at the table that comes back. The "Offset" column shows the offset, in milliseconds, between our local fuzzies. Host 15 is the WWVB clock, host 14 the WWV clock and host 11 the GOES clock. Host 9, often far out of whack, is a 4.2bsd Sun with either a fractured crystal or an hourglass. The dispersion in all the hosts is seldom more than a few tens of milliseconds. There is a systematic offset between the WWV clocks and the GOES clock of about 50 milliseconds which we have not been able to explain. Dave -------
tcp-ip@ucbvax.ARPA (06/19/85)
From: cperry@mitre (Chris Perry) Dave, "The night the clocks stopped" is obviously going to be a chapter in your Book. Better tell Padlipsky he's got competition. Just reading your description of BBN-META's mischief makes my Vulcan blood boil. Chris
tcp-ip@ucbvax.ARPA (06/25/85)
From: mills@dcn6.arpa Folks, A violent electrical storm wandered by our offices late this afternoon about 21Z and killed several traffic lights, an Ethernet board, two radio clocks and an unknown number of erroneous timestamps hiding all over the Internet. Our WWV secondary clock began ticking again after the static crashes died down several hours later about 02Z, but our old faithful WWVB primary clock didn't tick until late evening after 03Z. Even now the GOES tertiary clock in our next-door neighbor net remains unreachable (due dead Ethernet board). It was a bad day for clockwatching. Once again, my apologies to all our ICMP, UDP and TCP clockwatchers. Turns out the only UPS in our building runs the cypherlocks and security monitoring system. We are considering pilfering a few watts from it to run at least the primary WWVB radio reference. The irony of such a heist from such a source is too yummy to resist. Pun intentional. From the DCN-GATEWAY log it is apparent that a good clock service is moderately important to this community. However, our recent experience with primary-power disruptions suggests other sites may wish to share their clocks with the rest of us. All it takes is a WWV receiver (Heath GC-1000 - about $300), a dipole slung over the nearest tree (out of the near-field radio hash from the computers), a spare serial port and a cup of software. Season with UDP and serve on your nearest gateway. Dave -------