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CONTENTS 1 Introduction 4 Networks 5 Future Work |
Multimedia in the Teaching Space
4.5 THE ROLE OF ATM NETWORKS - THE METROPOLITAN AREA NETWORKS4.5.1. The development of the London MANWhat is a MAN? A MAN aims to serve a geographic area beyond the scope of LAN technologies, yet is restricted by some well defined community of interest, often a city. A MAN will often provide interconnection between sites of the same organisation as well as interconnecting organisations. This means that MANs have to provide performance close to that obtained on LANs yet cope with the interaction of multiple management domains. As a consequence the establishment of a successful MAN requires the correct balancing of a number of technical and political factors. Historical background London is a natural area for the development of an academic MAN, with more than 20% of the Higher Education Institutions (HEI) in the UK located within a relatively compact area approximately 50Km in diameter. However, the establishment of a co-operative venture between a group of independent organisations does not often happen without some particular stimulus to overcome inertia. This did not arrive until 1994, but a review of the academic networking arrangements in London before then will set the scene. Two changes in the late 1980s led to the break up of the University of London network. Firstly, within the federation of the University of London a greater degree of autonomy and control was given to individual colleges. A number of colleges merged into larger units and, for the purposes of computing services, the Schools and Institutes were grouped into seven Clusters, each led by a large computer centre. The second factor was the replacement of the Computer Board of the universities and research councils with the Information Systems Committee, which had significantly less central control over IT spending in universities. The result of these two changes was that the components of the University of London wanted to exercise their new found independence by providing their own networking. The federal network was replaced with a number of independent networks based on the Clusters, each with a single link to ULCC for connection to JANET. Throughout this period networking in the polytechnics was substantially underdeveloped due to the absence of the top sliced funding that had assisted the development of university networking.
A separate analogue video network (LIVE-NET) (see section 2.3 Legacy networks)
within the University of London provided a number of useful inputs into the
development of national networking and the London MAN. It demonstrated that
co-operation across distinct management domains was possible - LIVE-NET thrived
at the time when the federal X.25 network was being dismantled. It was an
important component of "Shoestring", the national pilot IP network, operating a
bridged IP network over analogue channels of the video network. Many lessons
learnt from the use of the video conferencing services have provided direct
input in the plans for the SuperJANET video conferencing network.
The sites connecting to the network in the first phase are: The primary requirement on day one of operation of the MAN was for a routed IP service. However, there is a clear requirement, within a short timescale, for a multi-service network that will support voice, video and data. Consequently, an Asynchronous Transport Service (ATM) network has been provided to all sites from the start. ATM is a technology specifically designed to carry delay critical traffic such as voice and video as well as more tolerant data traffic. Many of the features of the full service, such as dynamic allocation of bandwidth are not yet fully implemented, but ATM is now sufficiently stable for service deployment in a well managed environment. As well as the full IP service, the London MAN will offer a pilot ATM service to facilitate service and application development. The core sites are connected by a dedicated 155Mbit/s ATM ring, and a router at each core site provides the IP service. The connections to leaf sites are 34Mbit/s PDH circuits. At the leaf site they terminate in ATM switches and there is also a router for IP routing. The MAN supports a wide range of services. The IP service supports all standard INTERNET services, such as remote terminal access, file transfer, electronic mail and information access including the World Wide Web. With the bandwidth available on the MAN the IP service will also provide good support for the voice and video based services that are emerging. The ATM service will provide a guaranteed high quality video and voice services as well as an ability to allocate specific portions of the MAN bandwidth to particular applications or groups of users.
The initial topology of the London MAN Teaching Applications The basic services provide users of the network with a set of tools that will assist them in their learning, teaching and research activities. In the early days of computer networking the largest users were from the science and technology faculties, but now use of computers has spread to all disciplines. Some of the most demanding applications are in the arts subjects, where the network was of no use until it was capable of transferring high quality images at reasonable speeds. The use of electronic mail in the academic community is particularly widespread and, though it is relatively undemanding on network performance, it is an application that is heavily relied on. Access to information servers, and particular the World Wide Web, is the fastest growing area of network usage. The availability and quality of information is still very variable from subject to subject, but something can be found in most areas. The traditional libraries are evolving into learning resource centres and rapidly embracing new forms of electronic delivery of information. Libraries and their customers will be major users of the MAN, which will enable learning resource service to collaborate effectively across institutional boundaries. A major revolution can be expected in the way that teaching is delivered over the next ten years. Students will no longer be required to sit in the same lecture theatre as the lecturer or even to be participating at the same time. Remote delivery of teaching material will take a substantial time to develop and in the longer term will probably not even require the student to physically attend the university, with lectures being delivered to the home. The London MAN will provide video and associated services that will allow these teaching and learning methods to be investigated and developed. One benefit would be to reduce the amount of travelling between campuses of multi-site institutions, which is a particularly unpleasant activity in London. The MAN is also a mechanism to enable the collaborative development of course material involving multiple institutions. Video conferencing has applications in most areas of HEIs activities. The technology is still evolving and there is also much to learn about the human factors involved. Pilot video conferencing facilities on the MAN will allow development of the technology at the same time as providing an initial service to those sites with immediate requirements. Conferencing facilities can be linked to the national SuperJANET service and commercial services in order to communicate with a larger community. 4.5.2. Connectivity between MANsIt is possible to link with other MANs in UK, and a selection is given in the list below. Other MANs are proposed so that in due course there will be a distribution of MANs around the whole of UK, connected together by a CONNECT highspeed network. Aberdeen - AbMAN Bristol Edinburgh - EaStMAN Fife and Tayside - FaTMAN Glasgow - ClydeNET Manchester - G-MING South Wales 4.5.3. The Scottish MANsThis section describes the activities on one of the Scottish MANs, namely EastMAN, the Edinburgh and Stirling Metropolitan Area Network. There is considerable interest in both public and private sectors in the construction of MANs in order to integrate networking provision, achieve high speed connectivity both locally and to external networks (such as the INTERNET) and to make cost savings over self provision. Indeed, early access to and acquisition of the networking infrastructure supporting high bandwidth is perceived as a pre-requisite for the exploitation of multi-media and multi-service applications which are now appearing in the marketplace. The following paragraphs provide some informative detail on the initiative by the four Universities: Edinburgh, Heriot-Watt, Napier, Stirling and the three Higher Education Institutions: Edinburgh College of Art, Moray House Institute of Education and Queen Margaret College to create EaStMAN, the Edinburgh and Stirling Metropolitan Area Network. The network must be able to support new generation applications, for example, video conferencing, video on demand and multi-media for teaching, self directed learning and research as well as supporting the normal data and voice requirements of the MAN partners. At this time, there are various MAN awareness programmes running to stimulate the user community into consideration and deployment of new and familiar applications which can be supported on the FDDI and ATM high-speed network. Access to or connection to SuperJANET is an important service in the UK Academic Community. Connection to SuperJANET through high speed interfaces will allow access to and delivery of new services, e.g. electronic publishing, voice, and video, throughout the highly connected UK Academic Community. Links to Further Education colleges and schools are seen as important in the short term, both in pursuit of our aim to increase access and develop schools liaison, and to establish and expand distance learning interests. EaStMAN partners place great emphasis on the extensive use of technology in teaching and learning, and in the associated management and administration. Areas of particular interest include multi-media, computer-based learning environments and distance learning. The support of these areas requires access to the highest affordable bandwith and ATM (and is successors) is/are seen as the medium to long term bandwith development strategy. All HEIs are aware of the changing nature of user applications towards support of multimedia capability, sharing of data structures, conferencing and so on. Of particular importance to the Universities is the potential for interactive distance learning through video in conjunction with image databases as well as the enhancement of research tools using the same types of applications. This change is accelerating. Naturally, such applications can require large amounts of bandwidth, if not to support a single application then to support the sheer numbers of its users. Indeed, the first network applications on SuperJANET all concern multimedia or visualisation experiments e.g., surgery teaching, supercomputer data visualisation and interaction, special datasets (rare document access), electronic journal testbed, remote consultation (pathology), remote sensing data (browsing earth image files), group communication (Pandora at Cambridge - networked advanced desktop) and so on. We will also prepare for and stimulate multi-media applications such as computer-based teaching/learning and video-conferencing. Innovative teaching and learning systems are likely to be of increasing significance. |
Graphics Multimedia Virtual Environments Visualisation Contents
