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[LDM #JOF-421815]: Not receiving NEXRAD3 data...

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  • Subject: [LDM #JOF-421815]: Not receiving NEXRAD3 data...
  • Date: Mon, 06 May 2013 16:35:15 -0600
Hi David,

re:
> Alright…here is an update on the feed.  It appears that the 1 hour lag is 
> gone…but there
> remains a lag for some data.

Yes, we noticed that the situation improved markedly after splitting
the NEXRAD3 feed.  This reaffirms the view that the problem is related to
the bandwidth used per connection, and gives hope that further tweaking
could improve things further.

re:
> The only place where there is a lag is in the request for
> the pN[0-3] radar data.

Correct.  This is what we were hoping for (the improvement,
not the continued problem, of course).

re:
> During the day…I have seen the lag as long as 30 minutes…but it
> seems to correct during the evening.

Networks are typically less used at night, so this is implying
that there may be an overall congestion problem.

re:
> Would it be appropriate to split the feed further

Yes.

re:
> into:
> 
> pN0[A-Z]
> pN1[A-Z]
> pN2[A-Z]
> pN3[A-Z]

Yes, I think that this is the direction to go.  The REQUEST lines
would be:

request NEXRAD3 "/pN0"     idd.unidata.ucar.edu
request NEXRAD3 "/pN1"     idd.unidata.ucar.edu
request NEXRAD3 "/pN2"     idd.unidata.ucar.edu
request NEXRAD3 "/pN[3-9]" idd.unidata.ucar.edu
request NEXRAD3 "/pN[A-Z]" idd.unidata.ucar.edu
request NEXRAD3 "/p[TPD]"  idd.unidata.ucar.edu

The reason for the "/pN[3-9]" is to catch products on non-standard
tilt angles (e.g., /pN5Q, etc.).

re:
> Let me know what you all think…

Further splitting of the feed is definitely called for.

Comment:

- if the latencies are, in fact, caused by overall network congestion,
  further splitting of the feeds will exacerbate the congestion problem, not
  alleviate it

Cheers,

Tom
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Ticket Details
===================
Ticket ID: JOF-421815
Department: Support IDD
Priority: Normal
Status: Closed