High performance communications activities are a highly productive HPCC Program area. During the past year we have seen continued explosive growth in the use of high performance communications for information access, research at the frontiers of science, and commercial endeavors. High performance communication activities include continued research and development in internetworking technologies to support these new communities and applications, research into network systems operating at a billion bits per second and faster, wireless technologies, integrating computing and communication across wide areas, and enhanced Internet connectivity.
The Internet was created by ARPA, and that agency, other HPCC agencies, and industry and academia have contributed to its evolution and phenomenal growth (details about its evolution are given below). As new communities of education, commercial, public sector, and individual users join the Internet, fundamental changes must be made to support increased use, new applications such as video and imagery, service quality, security, and new modes of communication. Internetworking R&D supports these activities across the HPCC Program.
Work at ARPA, NSF, and other HPCC agencies in protocols is directed at ensuring that different types of networks continue working together as a cohesive system. New services, such as multicast and guaranteed service quality, are being created, evaluated, and introduced. Research into new routing and scaling techniques for extremely large networks anticipates an Internet that interconnects millions of sub-networks and billions of end users across an increasingly diverse set of media. Network security from the perspectives of protecting the network and protecting users is being incorporated into the fundamental operating principles.
The Evolution of the Internet
The Internet began in the late 1960s with the development of ARPANET. ARPANET provided a limited number of researchers with shared, interactive communications between computing systems at different locations and developed key innovative technologies on which the Internet still depends. Some of these include:
While initially an experimental system, the need for a stable network emerged as the user community grew. MILNET was split from the ARPANET for use by Department of Defense users. Federal agencies established networks to support their R&D communities: NSF created NSFNET for the university research community, NASA built the NASA Science Internet (NSI), and DOE created the Energy Sciences Network (ESnet). These networks and an ever growing profusion of local area networks and regional networks form the HPCC component of the Internet, a "network of networks," and demonstrate the fundamental strength of new networking technologies created in the early ARPANET.
The recent phenomenal growth of the Internet beyond the HPCC community is the result of educational, public service, private sector, and personal investment. Today there are more than 27,000 networks in the U.S., an increase of 350 percent over that reported on these pages a year ago. Non-U.S. networks number more than 21,000, an increase of 225 percent. More than 1,500 U.S. colleges and universities, 1,500 high schools and 1,700 elementary schools in the U.S. have full Internet connectivity.
The HPCC Program has directly stimulated the emergence of a vigorous and highly competitive private sector industry in Internet hardware, software, and connectivity in which the U.S. is a world leader.
A major HPCC activity is the support of five gigabit testbeds jointly funded by ARPA and NSF with support from DOE through their national laboratories, and a sixth testbed funded by ARPA. Nine Federal agencies, thirteen telecommunications carriers, twelve universities, eight corporations, and two state supercomputer centers participate in these six testbeds that connect 24 sites. Transmission equipment and fiber optic cabling is provided by the carriers and industry at no cost to the Federal government. An important success of the gigabit networking project is the high level of cooperation among the academic, industrial, and governmental participants leading to new capabilities in the science community, new markets for the industrial community, and new visions for high performance communications.
HPCC-supported gigabit testbeds funded jointly by NSF and ARPA test high speed networking technologies and their application in the real world. Courtesy Corporation for National Research Initiatives.
One of the technologies further developed and deployed in the testbeds is Asynchronous Transfer Mode or ATM, a "fast packet switched" cell relay technology in which small packets of fixed 53- byte size are rapidly routed over a network. ATM is a technology being investigated by the HPCC Program and the U.S. telecommunications industry to integrate data, voice, and video services using a single protocol. "ATM/SONET" refers to transmitting ATM packets over a Synchronous Optical Network (SONET) link, a standard for transmitting data across fiber optic cable.
Some of the accomplishments of the gigabit testbed project are:
CASA is a 2.4 Gb/s SONET testbed connecting the NSF San Diego Supercomputer center (SDSC), the DOE Los Alamos National Laboratory (LANL), NASA's Jet Propulsion Laboratory (JPL), and California Institute of Technology (Caltech). Each of these sites has significant computing resources, and CASA focused on interconnecting these supercomputers. While LANL and the other sites are about 1,600 km apart, the link is 2,000 km long. This link holds world speed records of 500 Mb/s for TCP/IP file transfers and 792 Mb/s for raw HiPPI (High Performance Parallel Interface), a world record for host-to-host bandwidth-distance product of any ground-based testbed. The distance and speed presented new problems for network researchers. For example, in CASA there are over 800,000 bytes of data in flight at any instant. Any error in transmission causes unacceptable delay in processing. The CASA HiPPI/SONET gateway incorporates a forward error correction scheme to avoid re-transmission of data when an error is detected. The CASA testbed allows two groups of climate researchers, one in California and the other in New Mexico, each working on different parts of a problem, to combine their software models into a single metacomputer-based execution using heterogeneous computing systems.
Irradiation of healthy tissue was reduced in an experimental radiation therapy medical treatment planning application that was distributed over a 622 Mb/s HiPPI/ATM/SONET network in the VistaNET testbed. Calculations were performed on a Cray Research Y-MP and displayed on a Pixel Planes workstation. This application provided data for real world network traffic analysis.
The MAGIC (Multidimensional Applications and Gigabit Internetwork Consortium) project was established to develop a very high speed, wide-area networking testbed to address challenges in heterogeneous computing, distributed storage, coordination of multiple data streams, and techniques for managing the effects of network delays in a defense applications context. The MAGIC team demonstrated TerraVision, a terrain visualization application that allows a user to view and navigate through a photorealistic landscape. With the addition of GPS-derived (GPS stands for Global Positioning System) data representing positions of units and vehicles, multiple commanders can get bird's eye views of situation and flow during training exercises as shown below. TerraVision images are stored on a distributed set of Image Server Systems (ISSs) connected by a high speed network. ISS images are transmitted to displays at Fort Leavenworth, KS, or Overland Park, KS. Sustained rates of several hundred Mb/s have been demonstrated.
To create a three-dimensional terrain scene in real time, distributed storage servers transmit data streams containing portions of the image in parallel over a high speed network to a user's workstation. In this view of a military training facility, the real-time vehicle position is shown by the blue line.
The Advanced Technology Demonstration Network (ATDnet) is a recently inaugurated high performance networking testbed in the Washington, DC area. It is intended to be representative of possible future Metropolitan Area Networks. Initially architected by NSA and the Naval Research Laboratory and funded by ARPA to enable collaboration among DOD and other Federal agencies, ATDnet has a primary goal to serve as an experimental platform for diverse network research and demonstration initiatives. ATDNet provides an opportunity for early access and familiarization for the DOD, especially those components dependent on state-of-the-art information technology. Emphasis is on early deployment, operation, and management of emerging ATM/SONET networks.
Six Federal agencies participate. ARPA and the Defense Information Systems Agency (DISA) serve as co-chairs of the ATDnet program. other members are the Defense Intelligence Agency (DIA), NASA, the Naval Research Laboratory (NRL), and NSA.
In FY 1995 ATDNet is used for experiments in telemedicine, distributed simulation, security and encryption techniques, ubiquitous video teleconferencing, large ATM network signaling research, ship design and analysis visualization, and network experiments. New network management techniques for SONET and ATM systems are being developed that will give DOD fast-start access to equivalent commercial services once they are tariffed.
In FY 1994 NASA launched its Advanced Communications Technology Satellite (ACTS). ACTS provides a "network in the sky" and is capable of multiple low speed access, four 155 Mb/s full duplex connections, or a single 622 Mb/s full duplex connection. In FY 1995 NASA expects to demonstrate gigabit speed applications using ACTS in two experiments: "A Performance Study of an ATM/SONET Satellite and Terrestrial Network for an Engine Inlet Simulation," and "High Data ACTS Experiment for Performing Global Science: Keck (Hawaii) Telescope and Global Climate Model." ARPA and NASA will also demonstrate interconnection of terrestrial gigabit networks in FY 1995.
Additional gigabit networking R&D includes:
As part of its program in National-Scale Information Enterprise, ARPA is extending the information infrastructure into the mobile environment. This includes wireless communications and networking technologies described here, and supporting services for mobile information systems (described in Section II.4):
In FY 1996 NSF will support basic research in wireless networks, including transmission, networking, and computing issues. The objective is to enable network access in a secure, seamless, and highly mobile environment, and to enable the handling of voice, video, and data communications.
In FY 1995 and FY 1996 NIST plans to assess the vulnerabilities and security requirements of emerging wireless technologies and to assess performance and establish benchmarks.
R&D for Network Integrated Computing
The computing systems and instruments used in research on the Grand Challenges and the National Challenges, as well as on Defense Challenges, are located throughout the country, and the researchers who use these resources travel around the world. One goal of the HPCC Program is to develop a networking and computing environment in which the number of researchers working on a problem and their locations are incidental to conducting the research. Another goal is to enable the extension of such an environment to an ever larger user community. Activities include the following:
Enhanced Internet Connectivity
At the beginning of the HPCC Program in 1991, NSF was upgrading the NSFNET backbone to T3 speed, and by 1992 full T3 backbone service was operational. This was the first network to provide T3 service. Today, as the NSFNET program prepares to switch over to a new architecture described below, commercial network service providers are offering T3 backbone service as are several regional networks. In fact all regional networks routinely provide T1 (1.5 Mb/s) service or better on their backbones.
As the Internet community grows, higher bandwidth and enhanced service networks are needed to handle more users, the increased size of transmitted objects (for example, images and video), and new applications such as collaborative work in which voice, video, and interactive data are transmitted. In the next year HPCC agencies will continue to enhance Internet capabilities. Examples are: