Vision

This section discusses the developments with respect to communication. Subjects discussed are the growing transmission capacity of the networks and the integration of the current forms of telecommunications into the Digital Highway.

4.1.1 Current Forms Of Telecommunications

At the present time, there are three important forms of telecommunications: telephone, television and radio, and data communication between computers.

Telephone
Currently, the telephone network mainly serves for speech telephony, which is the direct telephone conversation between two people. The telephone network covers the entire world and it is the most extensive network there is. It is a hybrid network. Besides the cable network it also uses satellite connections for long distances and beam transmitters for short distances. At the present time, we see the advent of cordless mobile telephony, such as the GSM network in Europe.

Radio and television
Since the beginning of television and radio these media have been broadcasted on the air. In addition, a cable network for television and radio has developed rapidly over the past twenty years. In The Netherlands, most households have a connection to the cable network. The cable network offers a wide variety of Dutch channels, foreign channels and pay television. Nowadays, the broadcasting of radio and television on the air is primarily useful on behalf of car radios and households that do not have a connection to the cable network.

Data communication
The third form of telecommunications is that of data communication between computers. This currently takes place via the telephone network and via separate data communication networks.
Data communication started with the exchange of formal, alphanumeric messages, applications such as Electronic Data Interchange, used for example for invoicing, on-line transactions and the exchange of files between the computer systems of different companies. As of late, the exchange of informal data is increasing. This mainly concerns electronic mail, in which texts, pictures and multimedia documents are being exchanged. We also see the advent of videoconferencing, in the form of video telephony between two personal computers.
The growth of this informal type of data communication is related to the growth of the number of personal computer users, but also to the advent of world-wide computer networks such as the Internet and CompuServe.

4.1.2 World-wide Communication Networks

The Internet is a world-wide network of networks (30,000 networks). The development of the Internet is a good example of self-organisation. The network was first set up by universities to enable the exchange of information. Later on, all kinds of enterprises and private individuals sought connection with the Internet. The number of connections has now reached around 50,000,000 and it is growing rapidly. The Internet was set up around a number of main connections. The network has a large number of server computers that support the communication and the various forms of services in the network. The Internet is basically open to everybody. With a personal computer and a modem every person can call in on the nearest Internet server via the telephone network. In practice, this means that people can communicate with the entire world against local telephone rates.
The Internet is not just a network, many services are provided via the Internet. A few examples are given below.

Electronic mail
Internet users all have their own, unique identification. This makes it possible to send messages to a user, provided his address is known. E-mail also offers the possibility to add one or more files to a message.

Newsgroups
In the Internet, there is a wide variety of bulletin boards and panels where questions can be asked and discussions held on all kinds of subjects, such as politics, the weather and sports. There are also many panels for discussion of certain hardware and software. Do you have a question about a certain product? Place it in the right 'newsgroup', and you have a fair chance of getting the right answer.

File Transfer Protocol
The File Transfer Protocol (FTP) is a possibility to send files to servers, from where they can be picked up by other users. The files may contain data as well as software. Various servers, mostly of universities, offer a wealth of software through the Internet (Freeware, Shareware).

Remote Processing
Another use of the Internet is remote processing, in which a connection is made via the Internet with a server elsewhere. After logging in on this server, a programme can be run there, the results of which are displayed locally.

A network like the Internet is CompuServe, which is a more commercial network. CompuServe offers similar possibilities. Already, CompuServe users and Internet users are able to exchange messages. Before the end of 1995, CompuServe wishes to realise a better coupling with the Internet, so as to also allow for things like file transfer between the Internet and CompuServe.

4.1.3 The Digital Highway

Data communication will continue to grow. This has to do with social developments like the increasing complexity of our organisations, products and services and our growing need to exchange knowledge and data. A great deal more communication in required for us to be able to keep our society manageable and to allow it to continue developing.
Data communication grows along two different lines.

At work: company networks
The trend we see within companies is that internal network systems are beginning to replace the current central computer systems. Employees have a PC or a workstation on their desks, through which they are connected to the local company network. In this Local Area Network (LAN), larger computers are included as servers. External networks are starting to connect the network systems of different companies. PCs at home, or portable PCs can also be connected to the company systems through such Wide Area Networks (WAN). As a result, there is a growing communication via the networks, within companies, between companies and between companies and private individuals.

At home: home systems
In people's homes, we see an integration of consumer electronics (television, VCR and audio system), personal computers and telephone. The latest computers are already fitted for the reception of radio and television, playing audio-CD, CD-I and CD-ROM and for video phone. The integration will result in a home computer system in the form of a network (Home Area Network or HAN), to which personal computers, televisions and audio equipment are connected. By means of telecommunications, companies will offer multimedia documents to people's home systems.

The growth of data communication will result in the integration of the existing telecommunications networks into one network with a high transmission capacity, that will connect all local company networks and home systems. This network is called the Digital Highway.

The integration will be established through the combination of the current networks for telephone, cable television and data communication into one, world-wide network. To this Global Area Network (GAN), all local company networks and home systems will be connected. The GAN consists of two parts: a high capacity cable network for the fixed connections and an airwave network for mobile communication.
Eventually, people and companies will have only one fixed connection for all their electronic communication. All forms of communication - speech, sound, images and computer data - will be digital (in other words, data in binary code). With mobile communication, it will be possible to reach people all over the world.

The capacity offered by the current networks is not sufficient to send all this digital information. The future home systems will require 5 interactive High Definition Television (HDTV) channels to render multimedia products and additional room for video phone and data communication. The capacity required will be at least 500 Mbit/sec per household. Even greater capacity is needed for the connection of LANs of companies, especially when the companies will be communicate with other companies and people by means of multimedia documents.

The current telephone network is based on twisted pair. At present, it offers a maximum capacity of 144 Kb/sec when using ISDN (Integrated Services Digital Network). A major advantage of the telephone network is that almost all companies and households all over the world are connected to it. A drawback is the fact that the current connections offer insufficient capacity for the eventual Digital Highway.

The cable television networks in The Netherlands are based on coaxial cable. These networks have the advantage of offering sufficient capacity for video phone, television broadcasting and the ordering of films, in addition to which, 80 % of the households in The Netherlands have cable connections. A drawback is that companies are not connected and an even bigger problem is that the cable network is not a world-wide network. A limited number of European countries have cable television in the form of regional networks that are not connected to each other.

Glass fibre and ATM
To be able to offer sufficient capacity to send digital data over the Digital Highway, two technologies are important: glass fibre as the bearer of data, and Asynchronous Transfer Mode (ATM) for an optimal use of the transmission capacity of the networks.

Glass fibre offers a far greater capacity than coaxial or telephone. It is therefore already used in telephone and cable networks for high-capacity, long-distance connections. Only for the connections to houses and companies, glass fibre is hardly used as yet.

As a result of the great transmission capacity required, it is imperative that the backbone of the network be a glass fibre network. A network via the air (an Electronic Skyway), for which plans exist as well, is for now a good solution to be able to reach everybody all over the world, but it will eventually offer too little capacity.

The main advantage of ATM is that it considerably increases the capacity of all existing types of networks (glass fibre, coaxial and twisted pair). ATM is based on the principle that all data (speech, video and computer data) are sent in small digital packets of 53 bytes each. Each packet consists of 48 bytes of contents and a header of 5 bytes. A great advantage is that it is possible to send a number of messages in the same direction simultaneously, while the packets of different messages are sent in random order.
The top capacity reached with glass fibre and ATM in the laboratory is 100 Tb/sec. The calculated theoretical maximum is 800 Tb/sec.

ATM has a number of other great advantages.

• All forms of data (speech, video and data) can be sent through the network in random order according to one protocol. This equally applies to LANs, HANs and the GAN. The protocol is the same for all types of networks (glass fibre, coaxial and twisted pair).
• Between two nodes in the network messages can also be sent via parallel lines. This makes the transmission capacity almost unlimited, especially in the GAN.
• Users can choose at which speed (also known as band width) a message is sent. To a low capacity, for speech transmission, for example, a low price applies. To a higher capacity, for example for the fast transmission of a multimedia document, a higher price applies. This facility is called Switched Multi-megabit Data Services (SDMS).
• SDMS also compensates for the differences in speed between the various networks such as coaxial, glass fibre and twisted pair. It is therefore possible to couple different types of networks.

 

By making the existing telephone network or cable television network suitable for ATM, sufficient initial capacity can be offered to start on the Digital Highway. The various communication networks, such as the Internet, also consider using ATM shortly. In time, all networks will be combined into one great network and it is likely that every household will eventually get one glass fibre connection to offer them sufficient incoming and outgoing capacity. The current connections for cable television and telephone will then become obsolete.

Conclusion
The question is not whether the Digital Highway will be realised, but when and how it will be realised. This is not an easy question to answer. Technically and financially, the construction of the necessary infrastructure is not such a problem.
In The Netherlands alone, the costs for the construction of an Digital Highway will amount to around fifty billion guilders. This involves connecting households and companies to a high capacity glass fibre net with ATM, enabling all users to transmit to each other multimedia documents of HDTV quality. If the current telephone and cable television networks are used, the costs will be lower, but the available transmission capacity will also be less.

Another possibility of getting an Digital Highway is by upgrading the infrastructure of for instance the Internet and CompuServe by means of glass fibre and ATM. The Internet already offers part of the facilities that will be offered by the Digital Highway. In addition, a large number of participants, such as universities and publishers, are prepared to invest more in the Internet. An advantage is that the investments can be gradual, since it is not necessary to upgrade all of the participating networks and connections of companies and private individuals at once. It is not unlikely that the fact that businesses and private individuals have discovered the Internet will lead to the gradual development of an Digital Highway.

However the Digital Highway will come into being, it is of the utmost importance that it offers more than sufficient capacity. A high-capacity communication infrastructure stimulates companies to use it and offer new, high-quality products and services via the electronic superhighway. In view of the relatively low costs if the infrastructure and the still falling prices of networks, skimping on this post would be extremely unwise. The few billions this will save are completely out of proportion to the economic losses companies will suffer when it turns out that they are unable to offer many new immaterial products and services electronically via the network.