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20030611: data feed problems



>From: "Eric Pani" <address@hidden>
>Organization: The University of Louisiana at Monroe
>Keywords: 200306111400.h5BE0HLd016841 IDD

Hi Eric,

>For more than a year, we have been having serious data feed problems
>when our upstream site is at LSU (sirocco).  We have tried everything
>that we can, including contacting LSU repeatedly, but cannot seem to
>resolve the situation satisfactorily.  We have worked extensively with
>our network people and believe that the problem is at LSU.  We are
>basing this conclusion on the fact that, while sirocco was down and we
>were feeding from Unidata's thelma machine, everything was fine.  We
>received all data without significant losses.  However, once sirocco
>came on-line again and we switched over to them, we began to experience
>substantial losses of data.  Our fallback site is OU's stokes machine
>and we have used them in the past, but they are feeding so many sites
>that we tend to fall significantly behind in the data feed.
>
>Can you help us resolve this problem?

Absolutely.  Outside of network problems or throttling by things like
packet shaper, there is no reason that you should not be receiving
all IDD data with little to no latencies.

>Adam Taylor
>(address@hidden) is the person primarily responsible for our
>ingestor (tornado.geos.ulm.edu) and Chance Eppinette (address@hidden)
>is our network person.  If you need to contact people here, they are the
>two most familiar with the situation so I would suggest them.  I am
>getting into this because we cannot seem to get past the stalemate that
>currently exists.

This email is also going to Adam and Chance, so I think we will be able
to get to the bottom of the data delivery problem quickly.

Adam,

In order to diagnose the reception problem at ULM, we will need to have
the latest version of the LDM-6 installed on your IDD node
tornado.geos.ulm.edu.  LDM-6 is only available in source form, so it
will need to be built locally on your machine.  Also, we will need for
tornado to start reporting real time statistcs back to the UPC so we
can monitor your data reception.

Note:

We will gladly install and tune the LDM-6 on your system.  To do this
we will need logins as 'ldm' and 'root' (or, better yet sudo capability
in the 'ldm' account).  Please let us know if you would like us to do
the installation and tuning.

>Frankly, the situation has gotten so bad that we are considering going
>to a NOAAport system.  The cost there is not trivial so I want to make
>sure we have explored all avenues to resolve the IDM problems before we
>go down that path.  I just find it hard to believe that a site 6 hops
>away on I2 would have such data loses unless there is a problem
>somewhere.

I agree with you.  If you are on I2 and there is no traffic control
mechanism in place at ULM (e.g., packet shaper), then there is no
reason you should have any difficulty in getting a reliable feed from
any IDD relay node.  We are distributing significant amounts of data to
quite remote sites (the University of Puerto Rico, and the University
of Rio de Janeiro) using the LDM-6 with virtually no latency (sub 5
second), so there is absolutely no reason that you shouldn't get better
service.

>Anything you can do to help would be appreciated.

We will upgrade your machine as soon we are given the needed access.

>Eric A. Pani
>Assistant to the Provost and Vice President for Academic Affairs
>The University of Louisiana at Monroe
>700 University Ave.
>Monroe, LA 71209
>address@hidden
>phone: 318.342.3675
>fax: 318.342.1034

Tom Yoksas


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