Re: NLDM

Hi Rob,

We are not actively relaying data via the NLDM network and haven't for 
some time.  However, we are still interested in playing with NNTP-based 
data transmission as part of the bigger question of how to provide data 
access five years down the road.

Regarding what's available that you could use, we have only prototype 
quality code available, that is, it is not polished or well packedged 
for distribution.   The code that exists will pull data products out of 
an LDM queue as they arrive, wrap them as "articles", and post them to a 
local news server.  On top of that we built a statistics reporting 
module to track product arrival, latency rates, path information (to 
track the flooding algorithm's automated routing), etc.  This confirmed 
that the NLDM network could sufficiently relay and manage the volume of 
our IDD.  We also have the beginnings of a decoder wrapper that would 
allow us to use our existing decoders under an NLDM node as well as an 
LDM node.

The one piece that remains to be developed in order to drop an NLDM node 
into our IDD network is a bridge to take an article and put it in the 
structure required by the LDM.  This is an easy, straightforward task 
IMO - there has has just not been a pressing need to devote resources to 
doing this.  Nor are we able at this moment in time to devote resources 
to supporting an additional package, so we decided not to formally 
release this work.

We did, though, study the question fairly deeply of how NNTP-based relay 
compares to LDM-based relay.  I would summarize this by saying that 
overall NNTP-based relay provides more features and flexibility in a 
number of ways while providing at least comparable performance.  Also, 
the INN code is high quality - for the most part the developers have 
done a great job.  Still, we have decided against switching at least for 
now due to the high cost to ourselves and the community of changing 
protocols.  This is coupled with the fact the LDM is meeting our needs 
sufficiently well and will continue to do so for some time in the future.

Does this answer your questions?

I am leaving tomorrow for the AGU conference and will be away from my 
email until next Friday.  I'm happy to answer more questions when I return.

Sincerely,

Anne


Rob Dale wrote:
> Is this project still ongoing? I'm working with a group of amatuer NOAAPORT
> hobbyists and one of the members has developed a procedure to send NOAAPORT
> data out via NNTP (news.noaaportemwin.net). I am working on getting that
> data fed into LDM, but before going too far wanted to know if your work is
> in progress and/or what you have developed available for us to utilize.
>
> We envision getting something similar to the IDD feed for non-university
> "hobbyist" users who can't afford (or don't have room for) a big dish and
> can't access IDD.
>
>  - Rob

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Anne Wilson                     UCAR Unidata Program
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                                  Boulder, CO  80307
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