Topologies – A topologies is an arrange of cables in a LAN. The most common topologies are ,star, ring, bus and also a hybrid that got all of the mixtures in it.

Bus topologies-uses only one cable lines with two end points. At the end point there is a terminator that stops signals at the end of the cable from being reflected back into the network.

Advantages: they are cheap and easy to set up. Disadvantages-because one cable carries all the data, it can cause more break downs,

once a cable crushes its hard for the others to pass on data or receives.

Star topologies- has a central (hub/switch)and also a computer to which all the computers are connected.

Advantages- Each computers has its own cable and does not need to share the line, if one PC is broken down it doesn’t affect the others, new application can be easily added.

Disadvantages-if the central hub/switch breaks down then the entire network will stops working. Its expensive and more cable will be needed.

Ring topologies- is made up of PC in a closed chain or circle. Traffic can be in one direction around the circle or both direction if there a double circle.

Advantages-there is only one cable that is used to connect all the computers.

Disadvantages- If the ring is broken or the cable is not working correctly then the entire network will stop work.

Hybrid topologies- is an combined of a connected bus, star and ring. The bus is usually the backbones of the topologies with the network star hanging off it.

Discuss the advantages and disadvantages of coaxial, cat5 (5e or 6), fiber cabling and wireless. Which one is suitable for peer to peer or client/server and why. e.g. coaxial is suitable for peer to

peer but not client server. Fiber is suitable for client/server not peer to peer.

Category 5 cable (Cat 5) is a twisted pair cable for carrying signals. Fiber cables contains up to a thousand fibers in singles cable. Coaxial are used for carrying lower-frequency signals.

Discuss the Disadvantage and advantages. Fiber- is suitable for client server not peer to peer because of the costs. This cable

you can run for kilometers in distance which makes it more suitable for LANs. Since peer to peer wont ever leave the confines of your home and/or small business, fiber is overkill. Fiber is also great for Client/server LANs because of speed. It is capable of gigabit speeds and this is an advantage because of how many machines will be using the link.

Cat 5- is suitable for both LANs because its cheaper and affords high-transfer speeds e.g. 100mbps but its main disadvantage is you can’t run it very far before the signal fades e.g. 100metres.

Coaxial-is used In LANs, it supports data rates of up to 185 of Mbps. Disadvantages- It is more expensive than the twisted cable. Advantages- is easily tapped.

Fibre cable

Cat5 cable.

Wireless

Coaxial cable.

CHARACTERISTICS

TWISTED PAIR COAXIAL OPTICAL FIBRE

Max length w/out repeaters (meters)

100 185 2000

Materials Pair of copper wires Copper core with a surrounding mesh

Glass & plastic

Common uses LANS LANS Joining LANS

LAN topologies Star, ring bus Star, ring

Speed 10Mbps -100Mbps 10Mbps 10Mbps to 1Gbps

Max length w/out repeaters (meters)

100 185 2000

cost Cheap moderate expensive

Connection Wired- transfers data through wire and cable. Disadvantages- Must be protected from damage, and it take up spaces Advantages-Its cheap and widely available, and it also easy to install.

Wireless-moves data through air and spaces. One example of a wireless is a radio and the television.

Disadvantages- Advantages-its easy to get connected.

CSMA/CD - stands for Carrier Sense Multiple Access with Collision Detection.

It stop packets of information colliding on a network segment.

OSI Model-Stands for Open Systems Interconnection (OSI) model. OSI model fix the way things should be done by the software and hardware on a network so that communications can take place between hub/switch or two computer.

There are seven layers in OSI model and they are: the physical, data link, network, transport, session, presentation and application. each layer starting with the physical layer extracts the different part of the packet and this method works its way up to the application layer. When a data is sent, it begins at the application layer and goes down to the physical layer.

IP Addressing- stands for internet protocol addressing. Its a unique number that tells where each address is placed.

IP addressing communicates two or more computers together.

Data Transmission-when data is pass on between two pieces of equipment.

Simplex – simplex transmission direction in only one way. Its not often used because it not possible to send back a mistakes or control signals to the transmit end.

Half duplex- A half duplex can send and receive at one direction but not at the same time, Only one end transmit at a time and so the other end receives.

Full duplex-this data can travel both ways at the same time, and there is no need to switch from transmit to receive, like in half duplex.