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(a) Explain the meaning of the term protocol in computer networks. (3 marks) (b)...

      

(a) Explain the meaning of the term protocol in computer networks. (3 marks) (b) Describe the use of the following devices in computer networks: (i.) Multiplexors;
(ii.) Acoustic couplers; (iii.) Line concentrators;
(c) (i.) Explain how Integrated Systems Digital Network (ISDN) may be used in a business organization?
(ii.) Describe the type of computer network you would recommend for a large, country wide, commercial bank, with heavy data processing requirements at its four regional centers.

  

Answers


Gregory
a) Protocol
It refers to a set of communication rules for exchange of information. Protocols define speeds and modes for connecting one computer with another computer. An example of communication protocols is the Open System Interconnection (OSI) set of communication protocols which are used to identify functions provided by any network and to separate each network function into seven „layers? of communication roles.

b) (i) Multiplexors
These are communication devices that multiplex (combine) several signals for transmission over a single medium. A demultiplexor completes the process by separating multiplexed signals from a transmission line. Frequently, a multiplexor and demultiplexor are combined into a single device capable of processing both incoming and outgoing signals.

(ii) Acoustic coupler
This is a device used to connect a modem to a telephone line via an ordinary handset. The acoustic coupler converts electrical signals from the modem to sound via a loudspeaker, against which the mouthpiece of a telephone handset is placed. The earpiece is placed against a microphone which converts sound to electrical signals which return to the modem. The handset is inserted into a sound-proof box containing the loudspeaker and microphone to avoid interference from ambient noise. Acoustic couplers are rarely used today since most modems have a direct electrical connection to the telephone line.

(iii) Line concentrators
These are devices that combine data streams from many simultaneously active inputs into one shared channel in such a way that streams can be separated after transmission. The concentrator?s output bandwidth must be at least as great as the total bandwidth of all simultaneously active inputs. A concentrator is one kind of multiplexing device.

c) (i) How an ISDN may be used in a business organization:
ISDN

This refers to a suite of internationally adopted standards for end-to-end digital communication over a public telephone network. ISDN specifically refers to protocols that are utilized in order to provide potential for universal digital network with a series of standard interphases that will facilitate the connection of a wide variety of telecommunications equipment to the network. ISDN has the objective of making the network digital so that a variety of communications can be undertaken within the same line. ISDN is capable of integrating a variety of services for voice, data, video, images, etc on the same communication line. Through ISDN therefore, it?s possible to make use of one line for a variety of activities.

Business applications of ISDN include:
1. Videoconferencing
ISDN supports the real-time exchange of voice and video. This may be useful in meetings where the participants are in different geographical areas.
2. Shared electronic chalkboards
Ideas and illustrations can be distributed in real-time to remote locations so that people in other cities or other countries can participate in meetings.
3. Telecommuting
ISDN provides facilities for users to tap into central network resources from the privacy of their own homes and do so with the functionality of a network node.
4. Transmission of large amounts of data
For example transmitting the contents of a newspaper from the editorial office to the printers.
5. Computer-based training
ISDN supports the speedy broadcast of data from the node in the network where training is being carried out.

(ii) I would recommend a star network

STAR NETWORK
In this network, there are a number of processing sites linked to a central unit, which may be a host computer or file server. The four regional sites would constitute the processing sites. It may be noted that each regional site may consist of a subnetwork of computers. In addition to facilitating communication, the function of the central unit would be to provide control over the network. It could for instance be used to administer security over the network since all the regional sites are linked to it. The central unit could also be used to provide shared data storage in the form of a shared database of records for all the regional sites. Data processing could thus be distributed over the regional sites with the central unit being invoked only during exchange of messages between regional sites or when reference is being made to data stored on the central unit. The star network could take the following configuration:










Gregorymasila1 answered the question on March 28, 2018 at 14:40


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