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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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