Advantages of networking.

The second article in our series, 'Computers without tears', by TERRY CORBETT, explains the advantages of networking your computer systems and the various forms of networking available.

Networks enhance the power, versatility, and communication ability of microcomputers (commonly known as computers). The widespread use of microcomputers has led to a need to link them into a network so that there can be communication between machines. This means that datafiles can be shared by all users and thus when changes are made this only needs to be done to one datafile.

This aids efficiency as all users are accessing the same information and this information in its updated form is available more rapidly. The development of the Intranet, which uses the structure and protocols of the Internet on companies' internal networks, is leading to better communication, as Intranets can communicate with networks which use different protocols, for example Macintosh networks can now talk to Novell networks. The cost of networking microcomputers is within the reach of the smallest company.

There are two types of Local Area Network (LAN) available:

Client-server networks, which have a dedicated file server and peer-to-peer networks in which no single microcomputer acts as a file server.

Client-server LANs have one or more file servers, one of which manages the operation of the LAN. A file server is a hard disk microcomputer system which holds the programmes and datafiles. The file server provides all of the work stations on the network with the programmes and datafiles as requested. Users do not have automatic access to the datafiles held on individual workstations. Because of the cost of the file server this type is the most expensive.

In peer-to-peer LANs all of the microcomputers are equal and the resources of any machine can be shared by others on the LAN. This type is the cheapest but is only suitable to connect up to 12 microcomputers. When there are more than six users, the performance of the network will slow down.

Networks require a network operating system in addition to the microcomputer's operating system to control all of the movements of data within the network. An example of a network operating system for a client-server networks is NetWare by Novell.

In a LAN, the microcomputers and the peripherals that are connected by the network will be located in the same room or distributed around the building. Two LANs that are located fairly close to each other can be connected through a bridge. Two dissimilar networks can be connected by a gateway -- in this the protocol of the sending network is modified to that of the destination network so that they can be received (protocols are the communication rules for the network).

Network security. The users of a network can access any information held in the datafiles and thus the security of this information must be considered. The network will contain some information that is sensitive or confidential. Network security should be controlled by a network manager who has control of all aspects of the network, from setting individual user access rights, to keeping file servers behind locked doors. The network should be protected by establishing a set of security procedures. Basic precautions should include:

(1) Logging out if you will be away from your workstation for more than 15 minutes; (2) Using unusual passwords (containing letters and numbers) and changing them regularly; (3) Using deceptive filenames for sensitive data; (4) Consider using an audit trail to track all network activity.

Another consideration is that of back-up. With a client-server LAN it is only necessary to backup the file server, whereas with a peer-to-peer LAN, the hard disk of every individual work station must be backed up regularly.

The speed of a network depends on a number of factors and is difficult to assess. Although speed is extremely important, other factors have to be considered; these are price, technical support, ease of use and installation.

The speed of the individual work stations will play a role, the power of the file server's processor and its clock speed, together with the speed of hard disk access are all important factors when considering the hardware. With regard to programmes and datafiles held on the file server, the way these are organised can also affect the speed of access.

Open systems. An open system is one which is built to a standard that allows networks containing different types and makes of microcomputer to be linked (such as those using Intel microchips and Apple Macintosh). With open systems there is portability of programmes, but more importantly, they increase connectivity and communication between different networks.

International regulation

The International Standards Organisation have defined a model that is to be used when building open systems. The aim of this is to enable the networks of different manufacturers to communicate with each other. The model is called the Open Systems Interconnection (OSI). The model consists of seven layers. Levels 1 to 4 are concerned with the transport of data in a form understandable by the computer and the telecommunications controls that are required for this. Levels 5 to 7 are concerned with the users view of the information system.

Connections in networks. Network connections are made using twisted pair, co-axial or optical fibre cable. This is changing as radio networks are being developed. Microsoft (e-mail), Lotus (Network Notes) and WordPerfect are incorporating radio support into their groupware programmes using radio technology, including cellular and radio wave. Many experts believe that radio networks are essential for groupware programmes to develop their full potential. Most countries have allocated the 2.4GHz band for LAN use. Delrina are including the means to operate via radio networks in their communications packages (WinFax, Win-Comm).

Internet technology adapted

The Intranet. A development that has had a major impact on networks is that of the Intranet. This has developed because companies have decided that the principles used for information access on the Internet could be used to make information available to employees, on a real-time basis, on the company's internal network . The Intranet is the use of Internet protocols and structures on the company's network.

What this means is that the underlying technology of the Internet has been incorporated into the company's network. To be more precise it is the introduction of TCP/IP technology into the company's local area network (LAN) and wide area network (WAN) which has resulted in the widespread development of the Intranet.

TCP/IP stands for Transport Control Protocol/Internet Protocol. This is a collection of protocols that are combined into a piece of software known as a stack. Different parts of the stack are responsible for different parts of the connection process, from moving data packets across a network to negotiating the file formats with client software.

TCP/IP has had a major effect on the development of Intranets because it can be used on otherwise incompatible networks. Existing networks have their own protocols which have long made the integration of different systems and their relevant network protocols across companies a nightmare for network managers. For example the AppleTalk protocol and the SPX protocol are incompatible. This means that each system has to negotiate a protocol transfer via a network fileserver before they can talk to each other.

Having a TCP/IP stack on each system provides low cost inter-operability. Intranets link together a number of internal web servers (to Intranets what file servers are to LANs). Each consists of server hardware (typically multiuser UNIX or Microsoft Windows NT hardware platforms) and web server software, the latter enabling users to access the Intranet and locate/display data on each server site.

For ease of use, servers typically include search engines. Users key in a description of the information they want and the engine finds the relevant data stores, or home pages, from all servers on the network. Users then use browser software on their workstations to interface all web servers and display the pages. This browser/ server architecture also overcomes dissimilar system problems by allowing a full transfer of information between IBM, Macintosh, UNIX and Novell environments. This is important because Intranets are about accessing information on more than just a local scale. The ultimate aim is to have exchanges across wide area networks within multi-site organisations.

The implementation of an Intranet offers many advantages. All of the data on proprietary networks can be freed up, groupware and scheduling are easier to monitor and control of the network is easier with all users working on an open standards basis. Another important point is that the required Intranet software can be downloaded from the Internet without charge or at a nominal fee. However it should be borne in mind that adding TCP/IP to the company network will increase the costs of equipment (more RAM will be required), training and network management.