SS 1 WEEK SIX LESSON NOTE (ICT_323)

 



Ss1

TOPIC: COMPUTER NETWORK

Introduction


A network consists of two or more computers that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communication.

In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data.

Networking is the process by which two or more computers are linked for a flawless communication

Properties of computer network

1.       Facilitate communications: computer networks allow people to communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls and video teleconferencing.

2.       Permit sharing of files, data and other types of information: In a network environment, authorized users may access data and information stored on other computers on the network.

3.       Share network and computing resources: In a networked environment, each computer on a network may access and use resources provided by devices on the network, such as printing a document on shared network printer.

4.       May be insecure: A computer network may be used by computer hackers to deploy computer viruses or computer worms on devices connected to the network, or prevent these devices from normally accessing the network.

5.       May be difficult to set up: A complex computer network may be very costly to setup an effective computer network in a large organization or company.

TYPES OF NETWORKS

1.       Ethernet: Ethernet is a physical and data link layer technology for local area networks (LAN). Ethernet was invented by engineer Robert Metcalfe. When first widely deployed in the 1980s.

2.       Token Ring: token ring local area network (LAN) technology is a protocol which resides at the data link layer (DLL) of the OSI model. It uses a special three-byte frame called a token that travels around the ring. Token-possession grants the processor permission to transmit on the medium. Token ring frames travel completely around the loop.

3.       ArcNet: ArcNet is an acronym for Attached Resource Computer Network. It was developed by Datapoint Corporation in 1977. It is simple, inexpensive and flexible network architecture designed for workgroup-sized networks.

NETWORK TOPOLOGY

1.       BUS Topology: BUS topology is the simplest of network topologies. In this type of topology, all the nodes (computers as well as servers) are connected to the single cable (called BUS), by the help of interface connectors.

2.       Ring Topology: A ring network is a topology of computer networks where each node is connected to two other nodes, so as to create a ring. The ring topology connects computers on a single circle of cable.

3.       Star Topology: Star topology is the most common type of network topology that is used in homes and offices. In star topology there is a central connection point called the ‘’hub’’ which is a computer hub or sometimes just a switch. In a star network the best advantage is when there is a failure in cable then only one computer might be affected and not the entire network.

4.       Mesh Topology: In a mesh topology each computer on the network has redundant data paths. The mesh topology provides fault tolerance if a wire, hub, switch or other component fails. A diagram of a mesh network looks like a fishing net.

5.       Tree or expanded star: A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured work stations connected to linear bus backbone cable. Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.

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