Unidata

IDD Status May 1998

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Robb Kambic

The IDD had minor changes in the last couple of months. The vBNS changes have slowed down and most sites are "satisfied" with their data reception. I attended a workshop on vBNS and have devoted time to NOAA port problems.

Again, the vBNS connections has been the most significant development for the IDD. Currently there are 13 sites connected to the vBNS, 2 have work in progress and 2 have summer installation schedules. The data rate improvement has been an order of magnitude better that the commodity network with the vBNS sites receiving data within the 10-30 secs range most of the time.

Connected sites:

• University of Arizona
• Cornell
• Georgia Tech
• University of California at San Diego
• University of Illinois - Urbana/Champaign
• University of Miami
• University of Michigan
• North Carolina State University
• Pennsylvania State University
• UCAR
• University of Virginia
• University of Wisconsin - Madison
• University of Wisconsin - SSEC

  Inprogress sites:

• Florida State University
• Utah State University

  Pending sites:

• University of North Dakota
• University of Washington

  Attended NLANR (National Laboratory for Applied Network Research) workshop on March 30-31 1998. The main theme was how to implement, tune, and maintain vBNS applications. The vBNS is supported by one vendor MCI and the connections (gigapops) are up for bids by any vendor. The NCNE (National Center for Network Engineering) works directly with MCI to configure and solve the network problems. Many factors related to the IDD implementation were discussed but the list is extensive. A short list:

• Reliable multicast only as strong as weakest receiving site, also network flooding problems
• Configuring TCP window sizes improves bandwidth usuage
• Check router paths in both directions, return path could be problem
• Reserve bandwidth on vBNS links
• Static router configurations could improve performance
• Use NLANR support to solve problems

  Most current vBNS applications are short term usage of a few days with high bandwidth reserved. 90% of the applications are Virtual Reality cubes displaying the images at remote sites. These applications can withstand loss of data without any major problems. The IDD cannot withstand data loss, so it is in a different category.

  NOAAport data is being received at UPC for over four months. The products arrive in a timely manner but there is still a problem with the SSEC ingestor. Some of the products are combined with others because the ingestor has a problem in determinating the end of some of the products therefore it consumes the next product also. Over 90% of the NOAAport products are received correctly