Project Universe Shows Feasibility of Linking LANs Through Satellites.
For years, the Years, The
the seven decades of Eleanor Pargiter’s life. [Br. Lit.: Benét, 1109]
See : Time major satellite carriers have had continuing discussions with the landline carriers as to the relative merits and economics of satellite versus landline transmission. Somehow the landline carriers seemed to have the edge because of the flexibility and versatility of their systems to carry all kinds of traffic, yet experiments suggest that satellite transmission systems can overcome this problem rather quickly. In Europe, Project Universe has shown that a satellite wide-area network can successfully meet requirements for all kinds of data and voice transmission demands, and bring a new perspective to the problem of integrating the sophisticated communications needed in joint research and development projects among geographically distributed corporations, educational establishments and government agencies.
Project Universe is an experiment linking local-area networks Local-area networks
Computer networks that usually cover a limited range, say, within the boundary of a building. A computer network is two or more computers that communicate with each other through some medium. (LANs) by satellite. Creation of the high-bandwidth network provided the opportunity to research a number of new computer-science techniques for the first time:
* Individual computers at separate sites have been made to work collectively and simultaneously on a single problem.
* Distant computers have been accessed remotely with the same performance quality experienced by local users.
* Slow-scan television pictures and illustrations have been transferred quickly and efficiently from one site to another.
* Voice communications has been carried throughout the network.
The Universe Project is made up of Cambridge rings and other types of LANs at six sites in the United Kingdom, linked via the European Space Agency's Orbital Test Satellite The Orbital Test Satellite programme was an experimental satellite system inherited by the ESA in 1975 from its predecessor, the European Space Research Organization (ESRO).
The first of the pair of OTS satellites (OTS-1) was lost at launch in September 1977. (OTS See Office of Thrift Supervision. ), which is in geostationary orbit geostationary orbit
A circular orbit positioned approximately 35,900 km (22,258 mi) above Earth's equator and having a period of the same duration and direction as the rotation of the Earth. 22,370 miles above the equator. Earth stations consist of a three-meter-diameter dish antenna, 14-GHz radio transmitter and 11-GHz receiver, and the network links.
The Universe project is a collaborative venture funded jointly by the United Kingdom's Science and Engineering Research Council (body) Science and Engineering Research Council - (SERC) Formerly the largest of the five research councils funded by the British Government through the Office of Science and Technology. and the participating industrial partners. Coordinated by the Rutherford Appleton Laboratory The Rutherford Appleton Laboratory (RAL) at the Chilton/Harwell Science Campus is a UK scientific research laboratory near Didcot in Oxfordshire. It has a staff of around 1,200 who support the work of over 10,000 scientists and engineers, mainly from the university research (RAL 1. RAL - Rutherford Appleton Laboratory (UK).
2. RAL - An expert system. ), the academic sites are Cambridge University Cambridge University, at Cambridge, England, one of the oldest English-language universities in the world. Originating in the early 12th cent. (legend places its origin even earlier than that of Oxford Univ. , Loughborough University Loughborough University is located in the market town of Loughborough, Leicestershire in the East Midlands of England. The University offers degree programmes and research. of Technology and University College, London (UCL UCL University College London
UCL Université Catholique de Louvain
UCL UEFA Champions League
UCL Upper Confidence Limit
UCL University of Central Lancashire
UCL Upper Control Limit
UCL Unfair Competition Law
UCL Ulnar Collateral Ligament ); industrial partners are British Telecom The telephone and communications carrier that provides services in Great Britain and Northern Ireland. It used to be a division of the British Post Office, but was privatized in 1984 under Margaret Thatcher's administration. (BT), GEC GEC Gaseous Electronics Conference
GEC Gigabit EtherChannel
GEC Geriatric Education Center (US government; HRSA)
GEC General Electric Co.
GEC Google Earth Community (online community) Marconi Research and Logic Limited (Logica's US operation is based in New York City New York City: see New York, city.
New York City
City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. ).
The prime objectives of the project are to extend the application of packet data transmission procedures suitable for use on highly reliable high-speed LANs to the metropolitan or wide-area networks Wide-area networks
Communication networks that are regional, nationwide, or worldwide in geographic area, with a minimum distance typical of that between major metropolitan areas. Smaller networks include metropolitan and local-area networks. of the future. The project will also contribute to the establishment of standards for future information technology systems at all appropriate levels of the ISO (1) See ISO speed.
(2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. Open Systems Architecture. Experiments in data, next, image and speech transmission have been carried out on the wide-area network created by the project.
To date, network performance has been close to original expectations. Early problems with the reliability of the earth stations were traced to the practice of switching off earth station equipment during periods when the system was not in use. This was found to be inappropriate, and commercial arrangements to cover maintenance of the travelling-wave tubes had to be modified to enable them to be left switched on.
Early in the project it was decided that the earth stations would be of standard design, and that certain elements of the equipment used to mount the applications experiments would be common either to all the sites or to the sites that would participate in particular experiments. Commonality was a major benefit since it allowed problems to be sorted out at individual sites, and allowed a considerable amount of leap-frogging in extending and elaborating applications.
The economic balances between satellite and terrestrial systems and between circuit-switched and packet-switched networks and their satellite variants will not be able to be determined at an early stage in future commercial developments. Thus, commonality of protocols and flexibility in methods of disposing of traffic provide a significant advantage in enabling a network, or set of networks, to provide the optimum response from the point of view of both the customers and the carrier. Project Universe has shown that such commonality and flexibility can be attained--and experiments in these areas will continue. A Look at Some Key Applications
Key applications mounted on the Universe network include network monitoring The term network monitoring describes the use of a system that constantly monitors a computer network for slow or failing systems and that notifies the network administrator in case of outages via email, pager or other alarms. and control, distributed computing (1) The use of multiple computers networked throughout a wide geographical area, or the world via the Internet, in order to solve a single problem. See grid computing.
(2) The use of multiple computers in an enterprise rather than one centralized system. and file systems experiments, the establishment of distributed videotex videotex, communications service that is linked to an adapted television receiver or a personal computer by telephone lines, cable television facilities, or the like, and that allows a user to retrieve and display alphanumeric and pictorial information at home. data bases, tests of encryption and authentication (1) Verifying the integrity of a transmitted message. See message integrity, e-mail authentication and MAC.
(2) Verifying the identity of a user logging into a network. procedures, and the transmission of digitally encoded voice and image data.
The risk of data interception is particularly acute in a satellite netowrk, due to the broadcast nature of the downlink. Commercial applications will no doubt require protection from unauthorized interception or modification.
The Project Universe encryption experiment (conducted by Logica and MRC See Maximum return criterion. ) demonstrated the practicality of using the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. Data Encryption Standard See DES.
Data Encryption Standard - (DES) The NBS's popular, standard encryption algorithm. It is a product cipher that operates on 64-bit blocks of data, using a 56-bit key. It is defined in FIPS 46-1 (1988) (which supersedes FIPS 46 (1977)). (DES) implemented in either hardware or software for the secure transmission of information across a wide-area network. A protocol has been developed that enables the encryption services to be transparent to network applications.
The Universe program provided a unique opportunity to use a wide-area network with several different computer systems linked by a variety of networking protocols into an "open system."
For this project Logica adapted a design for a software support environment that could be distributed beneficially over a LAN (Local Area Network) A communications network that serves users within a confined geographical area. The "clients" are the user's workstations typically running Windows, although Mac and Linux clients are also used. . In the design it appeared to each user as if all the tools and resources were local to the user's computer, although in reality they were implemented on various machines throughout the wide-area network. The tools could include compilers, editors, interactive debugging systems and entire run-time environments. Resources included items such as printers, terminals and other peripherals. It was required that this be done for users on a variety of computers and operating systems Operating systems can be categorized by technology, ownership, licensing, working state, usage, and by many other characteristics. In practice, many of these groupings may overlap. , and the scope for modifying the system software was severely constrained.
The operation of this framework is coordinated by two central managers, a resource manager and a data base manager. The resource manager acts as a "marriage broker", matching up requests for tools and resources with those known to be free, and handling any conflicts or deadlocks that arise. The data base manager not only controls the movement of files around the network, but also imposes a scheme for accessing files. This means that users can be individually restricted from accessing certain areas, but are also required, for example, to update documentation and specification files if they update program source files.
The implementation of this design under Project Universe was intended as a demonstration, and only a subset of the design was implemented. The framework was put in place for three different machines, the data base manager was fully implemented, and a simple resource manager was built.
The videotex data base created for Project Universe contains summary information about each participant's work within the project. Standard UK videotex and full-screen videotex frame formats are used; information is accessed using a high-speed photo-videotex terminal. Ordinary text frames can also be displayed using a low-cost microcomputer programmed to emulate a videotex terminal. Videotex with Distributed Data Base
The remote access of information from other Project Universe sites is seen as the first phase in providing a videotex service with a geographically distributed data base.
The high speed (on the order of 0.5 Mb/s end-to-end) and intelligent characteristics (such as name servers and bridges) of the Universe network make it significantly different from networks for which Teletex Teletex (not to be confused with Telex or Teletext) was a ITU-T specification for a text and document communications service that could be provided over telephone lines. Teletex allowed for the transmission and routing of Group 4 facsimile documents. was originally recommended. Additionally, Teletex protocols were originally designed to run on common carrier networks: Packet-Switched Data Network (PSDN (communications) PSDN - Public Switched Data Network. ), Circuit-Switched Data Network (CSDN CSDN Circuit Switched Data Network (ITU)
CSDN Cisco Self Defending Network ) and Public Switched Telephone Network (PSTN (Public Switched Telephone Network) The worldwide voice telephone network. Once only an analog system, the heart of most telephone networks today is all digital. In the U.S. ). These characteristically have error rates greater than the one in 10 to the ninth power typical of LANs.
Experiments regarding the effect of Universe-type networks on the Teletex service and its communications protocol Hardware and software standards that govern data transmission between computers. The term "protocol" is very generic and is used for hundreds of different communications methods. A protocol may define the packet structure of the data transmitted or the control commands that manage the had three principal objectives:
* to evaluate the Teletex protocols' ability to provide text-transfer services across networks with very different characteristics from those for which it was originally intended. The new networks in this case were the Cambridge ring and the Universe wide-area network.
* To ascertain and solve the problems of implementing the Teletex service in a multi-LAN environment such as that created by the Universe project.
* To verify and evaluate the three very different implementations of the Teletex protocols that were being developed.
Initial tests verified implementations of the underlying network service protocol. Thereafter, tests of the full Teletex software were made, exposing some inconsistencies both in the implementations and in the (at that time) draft Teletex specification. These were successfully resolved and full interworking (standard) interworking - Systems or components, possibly from different origins, working together to perform some task. Interworking depends crucially on standards to define the interfaces between the components. was achieved between Teletex terminals and an implementation that was complete in high-level software.
The high data rate of the Universe network has been exploited to transfer slow-scan color TV images from a remote site, with reliable control of robots at the same remote site.
An entire frame or a smaller user-selected area can be transferred from one framestore to another. This allows more rapid updating of the main area of interest when transferring a continuous sequence of images; the remaining area can be updated less frequently.
At the remote site, two types of robots are interfaced to microcomputers of the LAN. To provide user control of the slow-scan image transfer and of the robots, a microcomputer receives typed instructions and forwards these in a suitable form to the local framestore or remote robot as required.
The Project Universe network has been used by a simple workstation to access several small picture data bases situated in a variety of locations.
A widely available, low-cost personal microcomputer is used to retrieve and display color pictures from picture stores situated elsewhere on the network. The pictures are composed of text, bitmapped images, graphics orders or combinations of these. The maximum amount of data in a picture is about 16 kilobytes. It takes only a few seconds to connect to the remote picture store, retrieve and display the picture. Pictures could therefore be retrieved quickly and easily from anywhere within range of the satellite whose effective range is the whole of Western Europe Western Europe
The countries of western Europe, especially those that are allied with the United States and Canada in the North Atlantic Treaty Organization (established 1949 and usually known as NATO). and much of Northern Africa. Handling High Data Rates
Experiments have been conducted to discover how the Universe network might extend access to a remote data base held on a computer to include a much greater variety of information types. Stored speech or sound, for instance, might be included within the data, as could graphics and facsimile images.
Such multi-media documents require very high data rates for their effective transmission: a page of text or videotex can be encoded, in say, 1,000 bytes, but it could take 1,000 times that to encode a page of facsimile data into digital form, with a corresponding increase in transmission time.
Communication over the conventional telephone network runs at about only 150 bytes per second. But on a LAN, very high data rates of hundreds of thousands of bytes per second are possible. This means that the transmission of large text files or of digitally encoded facsimile images around such a network could be accomplished very quickly. The limitation with conventional LANs, however, is that they are confined to a relatively small area--within a single building, for example, or just one city block.
The Project Universe network provides a way of extending the LAN concept to cover any geographical area. If LANs are linked by a satellite, then data can be transferred between two LANs (even if they are on different continents) at almost the same rate of speed as is possible within a single LAN. With satellite linkage, large and complex files can be transmitted between any two global points with relative ease and with great speed.
The Universe network has been designed to explore potential problems of the integration of voice, images and data, and to provide simple demonstrations of services based on such a network. Voice experiments include real-time voice communication and the development of speech-compression techniques.
Project telephones have been connected to a Cambridge ring using a simple, inexpensive interface based on a Z80 microprocessor. A specially designed board deals with the conversion of analog speech into digital form using 64 kilobytes per second A kilobyte per second (KB/s or KBps) is a unit of data transfer rate equal to:
The system is also linked to the electronic mail system; a mail shot is sent to the recipient whenever a voice message is recorded. The message allows the user to playback individual messages at any time.
Project Universe was the first attempt to extend local-area networking techniques to the much tougher and error-prone environment of wide-area networks, and in particular satellite links. From the start it was decided to implement the applications in parallel with the network, both to prove the network itself and to demonstrate some novel networking applications.
As an experiment it was an almost unqualified success. Many of the demonstrations have subsequently been developed into commercial products, and others have formed the basis for designs and implementations both in industry and academia.
Universe also demonstrated the value of collaboration between industry, government research laboratories and universities, and that such collaboration is cost-effective and contractually feasible.
With the coming availability of low-cost satellite channels and ground stations there will be increasing demand for data links to be handled this way. Project Universe has shown that it can be done.