Steve Chiswell
Steve Emmerson
Mike Schmidt
Jeff Weber
Tom Yoksas
2004-10-19
Real-time, self-managing data flows -- Unidata will foster
and support the existence of real-time data flows that encompass a
broad range of Earth-system phenomena, can be accessed with ease by all
constituents, and are self managing in respect to changing contents and
user needs.
--A goal of Unidata 2008: Shaping the Future of Data Use in the
Geosciences
LDM Status Report
LDM Versions 6.0.15 and 6.1.0 have been released since the last
report.
Steve Emmerson conducted an LDM training workshop at the NWS
Central Region Headquarters as part of the NWS's project to
establish a nationwide distribution system for NEXRAD Level II
data using the Internet and the LDM. The NWS paid all travel,
salary, and benefits. On-site LDM training is not finished.
We are waiting on the Eastern and Southern regions to let us
know when they would like a site visit for training workshop.
rtstats has been modified to report statistics in floating point
format. The new version, currently being tested at the UPC, will be included
in the next LDM release.
IDD Status Report
233 machines at 134 sites are running LDM-6 and
reporting real time statistics. Sites continuing to run
LDM-5 are being encouraged to upgrade to LDM-6 as quickly as
possible. Unidata staff have remotely installed LDM-6 at many sites
to expedite the changeover process.
Real time LDM statistics can be found in the Real
Time IDD Statistics webpage. The topology and data flow information
reflects changes in feed requests within a few minutes of changes. rtstats
have proven to be most useful in diagnosing reception problems
at sites, especially when universities have implemented restrictions
on packets volume in and out of the campus without regard for
their user needs.
In order to correctly guage real-time status of the IDD, it is
important for all sites participating to accurately maintain their
clocks (easily done through Network Time Protocol software and servers).
NWS is using LDM-6 to move NEXRAD Level II data. LDM-6.0.14 was installed
in the initial distributed build. Results of performance monitoring studies
being conducted by NOAA personnel (Blanchard) are being shared with the
UPC. Information gained is being used to guide code modifications that will
be included in future releases.
The NWS transition from the CRAFT distribution network (built by OU)
to their own network that relies on use of Internet2 is proceeding on
schedule for completion in the early to mid-October timeframe.
Unidata has obtained and tested several DVB-S receivers to prepare for the
NWS migration
from the current operational broadcast of NOAAPORT data streams to a DVB-S based
system. Tests have shown compatibility between the Unidata developed software
used to ingest the NOAAPORT data feeds and the DVB-S broadcast stream
implemented by the NWS for evaluation. Comparison of performance characteristics
of Novra hardware used to receive the DVB-S signals revealed discrepancies
in firmware versions among units. Older units have had firmware upgrades
to match the units being deployed by the NWS.
