Networking…By: Allan Joe

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Content• A network• Standalone• LAN• Advantages and disad

vantages of LAN• Cables LAN• Wireless LAN• WAN• More detail on WAN• Client• Server• Peer to peer network

• Router• Network Topology• Bus topology• Advantages on Bus• Star Topology• Advantage and disadv

antages of star• Ring Topology• Data Transmission• I.T Definitions (1)• I.T Definitions (2)• Bibliography

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A Network

A network (or sometimes known as a computer network) is the interconnection between hardware components and computers which enables: —Communication—Sharing of resources—Sharing of information

Some examples of networks are: •Local area network (LAN)•Wide area network (WAN)•Internet•Intranet

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Standalone• A standalone is a device, application, computer, etc that can

function independently without the use of other devices. • An example would be an application that does not require the

internet or any other software or plug-ins except for the OS to work.

• Usually integrated devices (not standalone devices) are much more cheaper as they are used for more general purposes. While a standalone device is used for specific purposes which enable more customizations for that particular purpose.

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Local Area Network (LAN)

LAN is a computer network that interconnects computers in a limited area such as a home, school or office.

In a LAN, all the computers connected in the network, can either run as an independent computer and as a workstation on the network accessing the information from the network server.

LAN allows the sharing of:• Peripherals• Information• Devices

Devices shared by a LAN include: • Printers• Fax machines• Modems

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Advantages and disadvantages of LAN

Advantages1. The workstations can share

peripherals such as printers, which keeps costs low.

2. Information, applications, and other digital items can be transferred easily between the interconnected workstations.

3. New application can be installed into the server instead of being installed in each workstation separately – Saves time.

4. It is very cheap to set up a LAN

Disadvantages1. If one workstation is infected, all

workstation can be infected with the same virus.

2. It usually takes a lot of time to set up a network due to its difficulty.

3. If the file server gets a serious fault in it, it could negatively effect all of the workstations.

4. A LAN network is supposed to be continuously maintained, and this usually cost lots of money. 6

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Cabled LANA cabled LAN is when the computer is actually connected with a wire in order to use the network. Opposite of wireless.

There are 3 main types of cables LAN used today: 1. Twisted pair: This is when two conductors are twisted together so

that no electromagnetic interface can occur. The twisted cables are made of copper and is mainly used at home or corporate businesses.

2. Optical fiber cable: This is a cable that contains multiple optical fibers which are covered by a thin layer of plastic. It uses light waves in order to transfer information, but is usually expensive.

3. Coaxial cable: This type of cable is used mainly in TVs and for home use. A Coaxial cable can be bent which makes it very flexible.

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Wireless LAN• Wireless LAN is something that links two or more devices

using wireless distribution methods such as emitting of waves.

• This wireless LAN is connected through an access point which is connected to the Internet.

• Wireless LAN have become more popular than cables LAN due to its ease of implementation.

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Wide Area Network (WAN)

A WAN can connect different networks together across a large geographical area, such as a city, country, or around the world.

Information in WAN can be connected through many ways such as: • High-speed telephone lines• Fibre optic cables• Microwave links• Satellite links

WAN are usually used by:• Universities• Large companies• Banks

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More detail on WAN• WAN are used to connect other LANs together, this is how a

LAN can access to the internet because the internet is the WAN itself.

• WANs are usually connected together through the use of the internet, leased lines or satellite links.

• On the right hand side is a good exampleof a how a WAN works using the LANs.

For more information go on to:http://www.bbc.co.uk/schools/gcsebitesize/ict/datacomm/2networksrev1.shtml

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ClientA client is an application or system that enable a computer to access a

particular service made available by a server.

There are 3 main types of clients which are:

• Fat Client: This client performs huge amounts of data process operations itself. Usually the fat client does not need the help of a server to do so, and is used in many personnel computers.

• Thin Client: These type of clients use the resources of another computer (also known as a host computer). Usually the thin client uses an application server to do the processing of huge amounts of data.

• Hybrid Client: This client is a mixture of the two clients mentioned above. Like a fat client it processes locally but it relies on a server for storage of data.

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ServerA server is a computer program which runs in order to execute the

requests of other programs (also known as clients).Usually a server is a physical computer which is dedicated to run

one or more services as a host.Servers often provide important services across a network to either

private users or within a large organizations via the internet.

Some examples of a server is: • Database server• File server• Mail server• Print server• Web Server

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Peer to Peer network

A peer to peer network is a computer network in which each computer in the existing network can act as a client or as server for other computers in the network.

This allows a shared access to files and peripherals without the need of a central server.

This type of network can be set up at home, in a business or over the internet.

The peer to peer network is mainly used for sharing:• Audio• Video• Data• Or anything digitally formatted

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Router• A router is the hardware used in order to connect a

computer to the LAN. • It usually forwards data packets between a computer

network. • For a router to work it is connected to two or more data

lines which Is connected to different networks.

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Network Topology A network topology is the layout pattern of the various elements of a computer.

There are two types of network topologies, which are:•Physical topology: This refers to the shape of the cabling layout used to link different devices. •Logical topology: This refers to the way in which the signal acts or the way the data is passed through the network from one device to the next.

A LAN topology is one type of network topology which has both physical and logical topology.

There are three main types of network topologies: 1. Bus2. Star3. Ring

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Bus Topology• The bus topology network is mainly used in LAN networks, and is

where all the nodes is connected to a single cable. Each computer or server would be connected to a single bus cable.

• When transferring information, a signal would be emitted from the source (sender) to the intended recipient (computer).

• This signal travels along the cable visiting each connected computer until its address matches the intended computer's address.

• There are two main types of Bus Topologies: 1. Liner Bus2. Distributed Bus

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Advantages of Bus • It is easy to set it up.

• The bus network can be easily extended.

• It usually cost less to implement the bus network.

• This is usually used in small networks, this is why it is so good for LAN.

• It is easy to detect error in a Bus network and fix it.

• It is very easy to maintain and manage. 17

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Star Topology• This like the Bus Topology is a LAN network intended use. In

Star Topology, all the computers or devices is connected to a central hub.

• One of the many advantages of the Star Topology is that it is easy to implement and is cost-effective.

• But the downside is that if one of the cables does not work or gets damages then it would effect the whole system.

• There are two types of Star Topologies, which are: 1. Extended Star2. Distributed Star

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Advantages and disadvantages of Star

Advantages• Very high performance – due

to efficient utilization

• There is isolation of devices, this prevents any non-centralised failure from affecting the network.

• Very easy to detect faults in the network, and also to extends it meaning adding other devices.

Disadvantages• If the central hub fails then

the whole network is disrupted.

• If more nodes are added, more cables and cabling would be required – increases cost.

• Data transfer and capability depends on the central hub.

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Ring Topology• The Ring Topology is a network that is set in a circular fashion, In

which data transmitted travels around the ring, visiting each computer.

• Each computer connected to the ring network resends the signal so that the signal is kept strong.

• A disadvantage to this is that if one connection is dead or stopped, it would effect the whole network in terms of sending data around.

• An advantage is that it is easy and cost-effective to implement it, and it sends data in fast way.

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Data Transmission

Data transmission also know as digital transmission or communication is the transfer of data from one point to one point.

An example would be the transfer of a word document from one computer to another computer.

Usually the data is transferred or transmitted through specific channels. Some of these channels are:• Copper wires • Optical fibers• Wireless modes (waves)

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I.T Definitions (1)• Bandwidth: The refers to the range of frequencies used for

transmitting signals.

• Narrowband: Something which operates over a small frequency.

• Broadband: This refers to a telecommunication signal or device which has a great bandwidth and is widely used in telecommunications.

• Baud: In telecommunication baud refers to the symbols per second. This is the amount of symbols changes to transmission medium each second.

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I.T Definitions (2)• Simplex line:

• Half Duplex line: This system provides communication in both direction, but only one at a time. It is very unpopular these days and rarely used.

• Full duplex line: This system provides communication also in both directions, but allows this to happen simultaneously. This is mainly used everywhere for communication.

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Bibliography• http://whatis.techtarget.com/

• http://www.gartner.com/technology/it-glossary/

• http://www.webopedia.com/

• http://fcit.usf.edu/network/chap5/chap5.htm

• http://www.inetdaemon.com/tutorials/networking/lan/topology.shtml

• http://dictionary.reference.com24

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