CISL Annual Report 2005 > CISL research plans

Networking research projects and technology tracking

Networking research projects:
NETS is a principal collaborator in several nationally recognized networking and data communications research and development projects. NETS hosts and presents at national and regional meetings on a variety of networking projects. NETS continued work on an NSF STI award for the Network Path and Applications Diagnosis (NPAD) project in collaboration with the Pittsburgh Supercomputing Center (PSC), and NETS contributed to the NIH BRIN (National Institutes of Health) (Biomedical Research Infrastructure Network) Lariat project. NETS assisted in the submittal of the NSF Chronopolis proposal.

National LambdaRail (NLR):
National LambdaRail, Inc. (NLR) is a consortium of leading U.S. research universities and private-sector technology companies building and operating an optical multi 10-Gb/s LAN-PHY network across the country. NLR's fundamental mission is to provide an enabling network infrastructure for new forms and methods for research in science, engineering, health care, and education as well as for research and development of new Internet technologies, protocols, applications, and services. As evidence of the commitment to this mission, NLR devotes 50 percent wave allocation to network research. This allows NLR to put the control, the power, and the promise of experimental network infrastructure in the hands of our nation's scientists and researchers. NLR aims to re-energize innovative research and development for next-generation network technologies, protocols, services, and applications. Marla Meehl serves on the NLR board and as board secretary. Scot Colburn and Peter O'Neil serve on the NLR executive committee.

TeraGrid:
NCAR is proposing to participate as a Resource Provider site on the NSF-funded TeraGrid. TeraGrid is an open scientific discovery infrastructure combining leadership-class resources at eight partner sites to create an integrated, persistent computational resource. Deployment of TeraGrid was completed in September 2004, bringing over 40 teraflops of computing power, nearly 2 petabytes of rotating storage, and specialized data analysis and visualization resources into production, interconnected at 10-30 Gb/s via a dedicated national network.

TeraGrid is coordinated through the Grid Infrastructure Group (GIG) at the University of Chicago, working in partnership with the Resource Provider sites. These sites include the National Center for Supercomputing Applications (NCSA) at the University of Illinois, Urbana-Champaign, the San Diego Supercomputer Center (SDSC) at the University of California, San Diego, the University of Chicago Argonne National Laboratory in Argonne, Illinois, the Center for Advanced Computing Research (CACR) at the California Institute of Technology in Pasadena, the Pittsburgh Supercomputing Center (PSC) at Carnegie Mellon University and the University of Pittsburgh, Oak Ridge National Laboratory (ORNL), Purdue University, Indiana University, and the Texas Advanced Computing Center (TACC) at The University of Texas at Austin.

The Hybrid Optical and Packet Infrastructure Project (HOPI):
Peter O'Neil is a participant on the HOPI Design Team. The mission of the HOPI Design Team is to provide a technical plan and ongoing feedback for integrating the HOPI resources into a testbed facility that can provide dedicated bandwidth for specialized applications and an experimental platform for testing future architectures.

When Internet2 was first organized in October 1996, a defining mission was to provide scalable, sustainable, high-performance networking in support of the research universities of the United States. The resulting infrastructure, comprised of campus, regional, and national components, is a successful and robust packet-switched network. In the next few years, however, it must evolve to take advantage of new optical infrastructures, and the HOPI testbed is examining future network architectures. In planning for the Abilene's next-generation architecture, HOPI is considering a hybrid of shared IP packet switching and dynamically provisioned optical lambdas. The term HOPI (for hybrid optical and packet infrastructure) is used to denote both the effort to plan this future hybrid and a testbed facility and to test various aspects of candidate hybrid designs. A white paper describes the plan for the currently installed HOPI testbed facility. The eventual hybrid network will require a rich set of wide-area lambdas together with switches capable of very high capacity and dynamic provisioning. Initial demonstrations of these capabilities were shown in iGRID '05 and are planned for SC05.

Network Path and Applications Diagnosis (NPAD):
A key missing piece of the end-to-end performance puzzle is that the current set of diagnostic strategies do not adequately account for the effects of network path delay. The NPAD project team is developing extensions to existing diagnostic tools that will effectively take path delay into consideration, compensate for a variety of delay times, and test the effects of these new diagnostic tools with network users and operators, using actual high-performance applications.

Due to recent insights gained from the past Web100 and Net100 projects, we can show that the missing piece of the performance diagnostic puzzle is that the symptoms of most application and network defects scale with increasing path delay. For example, a minor defect in a campus LAN might have an insignificant or negligible effect on an application running on a 1-ms path across campus. However, that same defect has a greater impact on performance when running on a long path across the continent.

In this project, we are developing new diagnostic techniques that include a suite of diagnostic tools and strategies for their use to test applications locally with a 100-ms virtual path, and then test each successive segment of the actual path extended with a virtual path to a total path delay of 100 ms. Such testing is beginning to expose otherwise hidden flaws and impediments that contribute to delay, since each component of the path and application can be tested in a context equivalent to an ideal end-to-end path, while ruling out other potential flaws. This is an NSF-funded project with the Pittsburgh Supercomputing Center. Alpha testing of the software tools is currently underway at PSC, NCAR, Internet2, and Duke University. Peter O'Neil, David Mitchell, and Pete Siemsen are participants from NCAR on this project.

Cisco University Research Program Funding — Investigating Large Maximum Transmission Units (MTU):
Over the last decade, we have witnessed a tremendous increase in raw network capacity. Today, we are seeing the ubiquitous deployment of cross-country 10 Gb/s optical networks and early standards efforts in support of 40 Gb/s and 100 Gb/s networking technology. As a result, long fat pipes (elephants) [RFC1323] are no longer a rarity — in fact they are becoming the norm. For example, NSF funded the 40 Gb/s Distributed Terascale Facility (DTF) [RB02], UCAID has built a sonet-based 9.6 Gb/s Abilene Network of the Future [Int02], and installation of a nationwide dark fiber optical lambda network called National LamdaRail is nearly complete. However, it is not clear whether these network capacity increases will actually result in comparable increases in application throughput performance due to a number of specific underlying technical issues and protocol limitations.

It is well known that bulk transport application performance has not kept up with network capacity increases. We believe that application performance has fallen by about two orders of magnitude relative to the raw performance of the underlying technologies. The goal of this effort is to work within the Path MTU Discovery (PMTUD) IETF working group to specify a robust method for determining the IP Maximum Transmission Unit supported over an end-to-end path.

This new method is expected to update most uses of RFC1191 and RFC1981, the current standards track protocols for this purpose. The proposed new method does not rely on ICMP or other messages from the network. It finds the proper MTU by starting a connection using relatively small packets (e.g. TCP segments) and searching upward by probing with progressively larger test packets that contain application data. If a probe packet is successfully delivered, then the path MTU is raised. The isolated loss of a probe packet, with or without an ICMP can't fragment message, is treated as an indication of a MTU limit, and not a congestion indicator. Peter O'Neil is the lead from NCAR on this project.

NOAA High Performance Computing and Communications (HPCC) Program:
NOAA has asked NCAR to participate with their proposal to the NOAA High Performance Computing and Communications (HPCC) Program, with no funds proposed for NCAR. NOAA and NCAR are making excellent advances in supercomputing and planning for the development of enterprise network architecture. However, NOAA and NCAR currently do not have a distributed network test facility for evaluating new network technologies, other than in local environments. NOAA and NCAR have developed a way to test and integrate new network technologies to gain vital experience for promoting NOAA and NCAR research and operations.

We are jointly developing an optical network testbed using Dense Wavelength Division Multiplexing (DWDM) by leveraging NOAA and NCAR's existing investment in a metropolitan fiber optics. This network testbed will provide a platform for integrating DWDM technology and determining how DWDM will best serve NOAA and NCAR research and operations. In addition, it will also address other important challenges. The optimization of data flows and server input/output at 10 Gb/s will require further study, testing, and tuning, and the question of how to secure data flows at this rate will also be addressed.

The DWDM network testbed includes a pair of optical network switches with Gigabit Ethernet (GbE), 10 GbE, and DWDM components to be procured and located at NOAA Boulder and at NCAR. An optical tap will also be part of the testbed to allow passive monitoring of all data flows. In addition, four 64-bit computer systems are being installed to transmit, receive, monitor, and secure the data flows. Two systems will be located at NOAA and two at NCAR. NCAR is co-sponsoring 5% of Scot Colburn's time and providing a rack of computer room space for this project.

Network technology tracking and transfer:
NETS tracks technology advances and usage trends via networking conferences, training classes, vendor meetings, beta tests, technology demonstration testing, email lists, networking journals, user conferences, and by meeting and exchanging information with universities and other laboratories. NETS staff continued to utilize all of these technology-tracking avenues during FY2005. New technologies are integrated into production UCAR networks on an ongoing basis after a given technology has met our capacity, performance, connectivity, reliability, usability, and other maintainability requirements.