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[LDM #HMA-788722]: LDM problem

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  • Subject: [LDM #HMA-788722]: LDM problem
  • Date: Tue, 25 Dec 2007 10:22:36 -0700
John,

> Merry Christmas.

Merry Christmas to you and yours.

> Sorry to lay this on you, but it looks like
> the NEXRAD2 latency is climbing again:
> 
> http://www.unidata.ucar.edu/cgi-bin/rtstats/iddstats_nc?NEXRAD2+adiabat.rwic.und.edu

Yes.  The upstream LDM is active on uni7.unidata.ucar.edu and the
downstream LDM is receiving the data -- but at a rate that's increasing
the latency.  I note that most of the other feeds are arriving in a 
timely manner for the CONDUIT data.  It could be that your network is
"packet shaping" traffic so as to slow down high-volume transfers 
(such as NEXRAD2 and CONDUIT).  We've seen this before; the signature
is high or growing latency for high-volume feeds and low latency for
low-volume feeds.

You might check with your networking people.  Do not be surprised,
however, if they say they aren't packet shaping and then the problem
mysteriously disappears.  We've seen that too.  Try to go sufficiently
high in the networking food-chain to reach someone with authority
(who still might say they're not packet shaping).

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: HMA-788722
Department: Support LDM
Priority: Normal
Status: On Hold