[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[LDM #PYO-163672]: Want to find out more about LDM

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: [LDM #PYO-163672]: Want to find out more about LDM
  • Date: Mon, 14 Oct 2013 13:02:12 -0600
Thomas,

> Hi,
> 
> One of our user has suggested we (PO.DAAC) to look into LDM.  I am done some 
> initial research on this and would like to find out more about it.  Could 
> someone help answer the following questions
> 
> 
> 1.  Is LDM a peer-to-peer aggregation service between data centers?

The LDM is more of a dissemination system than an aggregation system. The 
simple use-case is one in which data-products are being routinely generated by 
a long-lived site and need to be distributed to one or more other sites. The 
LDM support multiple simultaneous instances of this use-case.

> 2.  Is the purpose of LDM to ensure all data node have the same collection of 
> data artifacts?

No. Each "downstream" site is able to select what it wants to receive. Think 
publish/subscribe.

> 3.  I read some information about LDM uses RPC interface.  Is this interface 
> required by our users to find and download data?

No. RPC messages are used by the LDM to subscribe-to and transmit 
data-products. Typically, a user knows a priori what upstream site has the 
data-products in which they are interested.

> 4.  Does LDM support any other access protocols?

No.

> 5.  Any quick tutorial or overview presentation on who to use LDM on existing 
> earth science data archives?

The LDM homepage is <http://www.unidata.ucar.edu/software/ldm>. There are some 
links there that might prove useful.

The sites listed at <http://www.unidata.ucar.edu/cgi-bin/rtstats/siteindex> all 
use the LDM to receive meteorological and related data.

There are other sites that use private LDM networks to distribute data.

Feel free to contact me with more questions.

> Please advice, Thanks,
> 
> Thomas.
> 
> --
> Thomas Huang
> Jet Propulsion Laboratory
> 4800 Oak Grove Drive, Mail Stop 171-264, Pasadena, CA 91109
> Phone: 818.354.2747, Email: address@hidden<mailto:address@hidden>
> 
> DISCLAIMER: All personal and professional opinions presented herein are my 
> own and do not, in any way, represent the opinion or policy of JPL, NASA or 
> Caltech.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: PYO-163672
Department: Support LDM
Priority: Normal
Status: Closed