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Re: Yesterday's latencies

"Arthur A. Person" wrote:
> 
> On Tue, 25 Sep 2001, anne wrote:
> 
> >
> > Hi again Harry, Daryl, and Art,
> >
> > Harry and Daryl, thanks for the notification.  I just had a long
> > conversation with one of our network engineers.  The problem may simply
> > be congestion.  I need to contact them when it's happening.  I will try
> > to keep an eye on things, but I would appreciate it if, again, you would
> > contact me when you see it.
> 
> I'm now making an accumulation log of the .stats files each day so I can
> go back and check times.  In looking at yesterday's stuff, data seemed to
> be arriving in a normal amount of time.  The only oddity I noticed was
> ingestor.wunderground.com had high latency from 15-17Z but they also
> inserted relatively few bytes.  These good numbers don't mean there wasn't
> a problem, though, as Harry pointed out.  It may just be that the problem
> wasn't bad enough to cause a backlog, at least for our system.
> 
> I'm also running a traceroute to motherlode every 5 minutes and keeping a
> log.  I have it such that it's printing the ncar-abilene line on my screen
> every few minutes so I can see if the latencies go up.  If I'm at my desk
> and see the numbers go up, I'll email you.  So far, I saw one 5-minute
> period (@15:20Z) this morning when the numbers were 84.925 ms  227.015 ms
> 233.327 ms.  Other than that, things appear nominal today so far.  I would
> agree with Harry though that there would appear to be a problem with the
> ncar-abilene interface, maybe an intermittent hardware issue rather than
> just traffic... ????
> 
>                                     Art.
> 
> 
> Arthur A. Person
> Research Assistant, System Administrator
> Penn State Department of Meteorology
> email:  address@hidden, phone:  814-863-1563


Thanks for the support, Art.  

I'm trying to determine if the latencies are just from UCAR, or if there
are periods of network-wide latencies.  While it's clear that some
latencies are from UCAR, it's not clear that there aren't latency
problems elsewhere.

It's possible that the UCAR problem could be a hardware issue, but in
discussing it with the network engineer and viewing the statistics,
congestion seems like the most likely cause.  Our link to Abilene is
shared by about 10 colleges and universities.  We may be seeing the
typical late afternoon/early evening student use of lines.  We'll see
what happens today.

Please do email me if you have something to report.  Again, I appreciate
your help!

Anne
-- 
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Anne Wilson                     UCAR Unidata Program            
address@hidden                 P.O. Box 3000
                                  Boulder, CO  80307
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