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Berkeley Lab Team Develops Flexible Reservation Algorithm forAdvance Network Provisioning

December 13, 2010

Media Contact: Jon Bashor, jbashor@lbl.gov, 510-486-5849

Scientific research is becoming increasingly dependenton data-intensive analysis as larger teams of scientistsare generating, sharing and analyzing very largedatasets. Due to the geographical dispersion of theresearchers, networking support is critical to advancingthese efforts. Many applications need networkingsupport that provides predictable performance, which inturn requires effective algorithms for bandwidthreservations.

To address this need, the U.S. Department of Energy'sEnergy Sciences Network (ESnet) developed anddeploys a network reservation system called OSCARS(On-Demand Secure Circuits and Advance ReservationSystem). The system establishes guaranteed bandwidthof secure virtual circuits for a certain bandwidth andlength of time. However, OSCARS currently only gives ayes or no response to reservation requests. Userscurrently cannot inquire about bandwidth availability, nor receive alternative suggestions when reservation requestsfail.

To address this, Mehmet Balman, Arie Shoshani and Alex Sim of Berkeley Lab's Scientific Data Management (SDM)Group and Evangelos Chaniotakis of ESnet developed a flexible reservation algorithm for advance networkprovisioning. A paper describing the work was one of 51 technical papers accepted by the SC10 conference (outof 253 submissions) and was presented by Balman at the conference in New Orleans in November.

The SDM Group develops new methods and tools for moving and analyzing massive scientific datasets, while ESnetis DOE's network connecting more than 40 major research sites and peers with more than 100 other research andcommercial networks around the world.

The authors describe the algorithm as "a novel approach for pathfinding in time-dependent networks takingadvantage of user-provided parameters of total volume of data to be tranfered and time constraints for moving thedata." The algorithm's flexibility can be likened to looking for airline flights. While travelers can usually specify theirexact times and dates, many reservation systems can offer a number of options and lower fares if the traveler can beflexible regarding departures and arrivals.

Currently, when a scientist enlists OSCARS, the system checks network availability and capacity for the specifiedduration of time, and allocates it for the user if it is available. Otherwise, it reports that it is unable to provide therequested allocation. When this happens, it falls upon the user to use a trial-and-error approach to finding anavailable time for the required bandwidth. The new algorithm presents the user with a variety of possible reservationoptions and alternatives. For example, if a research team is up against a deadline for presenting findings, they mayopt for the earliest completion time of the data transfer. On the other hand, they may be able to wait for a time whenthe highest bandwidth is available, allowing the data to be transferred in the shortest duration. Users can thenchoose the option that best fits their needs.

Balman began working on the project as a summer student at Berkeley Lab in the summer of 2009 while he wasworking on his doctorate at Louisiana State University. He has since graduated and is now a staff member of theScientific Data Management Group at Berkeley Lab.

"It is an interesting problem that has come about with the development of bandwidth reservation systems such as

Berkeley Lab Team Develops Flexible Reservation Algorithm f... http://www.lbl.gov/cs/CSnews/CSnews121310.html

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OSCARS," Balman said. "Although we have implemented our algorithm for testing and incorporation into a futureversion of OSCARS, the algorithm is not specific to OSCARS, and can be used with any network reservationframework."

In the paper, Balman and his co-authors point to a couple of examples of next generation research networks that willbe increasingly important. In the area of high energy physics, the Large Hadron Collider (LHC) in Switzerland isexpected to generate 100 gigabits of data per second in the near future. This data is then quickly distributed to tiersof data facilities around the world for analysis by thousands of scientists in dozens of countries. Similarly, in the fieldof global climate research, the Earth System Grid (ESG) currently contains 35 terabytes of data shared by more than16,000 users worldwide; while the next generation climate data archive is expected to be hold than 5 petabyte ofclimate data.

Supporting such data-intensive science requires a communication infrastructure which enables large-scale datareplication, high performance remote data analysis and visualization, and provides access to computationalresources, in addition to reliably transferring the data across networks.

When they first looked into the issue of flexible bandwidth provisioning, Balman and his co-authors thought theproblem would be hard in terms of complexity. But on further examination, they realized that it can be solved inpolynomial time, and it can be implemented and integrated into the current network reservation frameworks in a veryeffective manner. The algorithm produces results in less than a second for current network configurations, and it isquite practical even if applied to future very large networks with hundreds or even thousands of routers and links, acritical factor as nearly all end-to-end network connections traverse multiple links across different networks.

Now that the algorithm has been implemented as a new service extending the current underlying mechanisms, theteam is integrating the algorithm into the next version of ESnet OSCARS, due out in early 2011. Additionally, they areworking on the coordination of storage and network resource provisioning.

Read the full paper.

For more information about computing sciences at Berkeley Lab, please visit: www.lbl.gov/cs

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