Networks

• Networks is a collection of computer devices connected together

Advantages

• Hardware, software and datas can be shared

• Easier for internal communication

• Centrally backup

• Easier to monitor the network activity

• Can access data from any computer

Disadvantages

• Network manager may be needed

• Security issue - files sent between computer may cause spread of virus

• If the server is down, all workstations on the network are affected

• High initial cost

3 Types of Networks

LAN (Local Area Network)

• A network where all computer system are all connected relatively close to each other, for example in the same building or schools

WAN (Wide Area Network)

• A network where all computer system are all located relatively far from each other, for example in different buildings all over the country or different countries.

PAN (Personal Area Network)

• A network where all computer system are all connected close to the user, for example in the same house

Network Toplogies

Topology of a network is the way in which the connection of the network are arranged

Bus Network

Advantages

• Easy to setup and add more workstation

• Quick to set up

• Cost-effective

Disadvantages

• Difficult to troubleshoot

• Limited cable length and number of workstation

• Problem with the cable, all workstation goes down

• Low security

• Data collisions

Ring Network

Advantages

• Quick Data transfer

• Simple data transmission

• Little to no data collision

• Can add additional workstation

Disadvantages

• If one workstation fails, the whole network is broken

• Problem with the main cable or connection, the whole network goes down

• Difficult to troubleshoot

• To add additional workstation need to shut down the entire network

Star Network

Advantages

• Fast network speed

• Easy to setup

• Able to add more workstation without shutting down the entire network

• Any non-centralised fail will have very little effect on the network

• Minimal network collision

• Better security

Disadvantages

• Expensive to install

• Switch/hub is needed

Switching

Data can travel around networks in two ways

• circuit switching

• packet switching

Circuit switching

• Provides a dedicated link between two nodes.

• No other data can be transmitted along the same route while the connection is open

• A landline telephone system is an example of a circuit switched network

Advantages

• Reliable

• Once it is setup, it is fast and usually error free

Disadvantages

• Take time to establish connection

• If anywhere fails, the whole connection fails

Packet switching

• Data is split up into small packets.

• Each packet carries the address of its destination.

• As the packet arrives at a switch or a router, the address is read and it is sent along the next free path.

• Each packet contains information about how many packets there are in the message.

• Each packet has information explaining where it fits into the message.

• Packets may arrive at the destination in a different order to which they were sent, but can reassemble using the information contained in the packet once all packets have arrived.

Advantages

• Do not need a dedicated line

• Can take alternate route

• Tends to error free

• High efficiency as if one packet fails to send, you only need to resend that packet

Disadvantages

• May arrive in wrong order

• May cause a delay until all packets are sent

• Large memory is needed to hold the packets

Mac Address (Media Access Control Address)

• A hardware address

IP Address

• Address of your network