LDM

Status Report: September 2012 - April 2013

Steve Emmerson, Mike Schmidt, Tom Yoksas

Strategic Focus Areas

The LDM group's activities support Unidata's strategic goals in the following ways:

  1. Enable widespread, efficient access to geoscience data
    The LDM powers the Unidata Internet Data Distribution (IDD) system.
  2. Provide cyberinfrastructure leadership in data discovery, access, and use
    The LDM allows sites to move data in their own environments.
  3. Build, support, and advocate for the diverse geoscience community
    The LDM is used by countries outside the US.

Activities Since the Last Status Report

LDM 6.11.4 Released

This version of the LDM has several new features:

  • It prevents a downstream site from wasting bandwidth by accidentally making redundant or overlapping requests for data to an upstream site;
  • It prevents an upstream LDM from wasting bandwidth by redundantly feeding a downsteam site; and
  • It mitigates a denial-of-service attack on an upstream site.

Incorporating these features into LDM 6.11 was more difficult than anticipated.

Two-Year Report on VCMTP Sent to NSF

For the past two years, we've helped Professor Malathi Veeraraghavan of the University of Virginia (UVA) investigate the possibility of incorporating multicast capability using virtual circuits into the LDM (the LDM is one of the major users of Internet2 bandwidth). This collaboration was supported by an EAGER grant from NSF and resulted in the development of the Virtual Circuit Multicast Transport Protocol (VCMTP) by graduate student Jie Li. The final report, "Towards increasing the usage of new high-speed network services by the scientific community", was sent to NSF.

Proposal for LDM-7 Sent to NSF

As a result of the success of the previous EAGER grant and an NSF solicitation, Professor Veeraraghavan (PI) and Steve Emmerson (co-PI) submitted proposal 1340910, "Leveraging DYNES for Weather Data Distribution on Multicast Virtual Circuits", to the Campus CI Networking (CC-NIE) group of the Office of Cyberinfrastructure (OCI) of NSF. They propose to do the following over 2 years:

  1. "Harden" VCMTP;
  2. Develop a module for the automatic management of multicast virtual circuits;
  3. Develop a multicast version of the LDM (mLDM);
  4. Integrate mLDM into the existing LDM-6 -- creating LDM-7; and
  5. Deploy LDM-7 to co-operating sites and evaluate it. The sites are: U of Virginia, UCAR, U of Wisconsin, Rutgers U, Boston U, U of New Hampshire, Colorado State U, MAX, RENCI, and Texas Tech U.

Planned Activities

Ongoing Activities

We plan to continue the following activies:

  • Support LDM users
    • Email, phone, etc.
    • Training workshops
  • Incrementally improve the LDM as necessary
  • Incorporate additional AWIPS-II-related changes into the LDM
  • Update table-driven decoding of GRIB products as necessary

New Activities

We plan to possibly take part in the following (depending on funding):

  • Development of LDM-7