Local Area Networks (LANs)

Key Words:

LAN-Local Area Network-One which covers a small geographical area and whose equipment is owned by the organisation/individual.

Node-The name given to any device attached to a network.

Switch- A device, which connects the computers in a LAN together that is considered intelligent, as it will route data to the correct destination.

What is a COMPUTER NETWORK?

Two or more computers connected together to share information and resources.

-this can also involve physical and wireless connections, or both.

What is a LAN?

A connection of computer and devices where each device is known as a node.

LANs are confined to one site and are small. Network infrastructure is property of the organisation.

ADVANTAGES:

• enables digital communication

• sharing of digital information

• sharing of peripheral devices

• updated with latest software from a central point

• distributed processing

  • ability to run a single program simultaneously at various computers

DISADVANTAGES:

• Requires expertise to install and maintain a large network which can be costly

• there are a number of security issues from unauthorised access to data:

  • measures to secure:

    • passwords - strong passwords

    • not allowing users to install software

    • with wireless access, use encryption

    • change passwords frequently

Factors affecting network performance

Bandwidth, topology, traffic and concurrent users, interference and transmission errors.

Bandwidth - carrying capacity of the network data transfer media

Topology - setup in different configurations

Traffic - Too many users slows down the network

Interference - certain devices can cause interference, corrupt data as it travels which will need to be resent, taking time and slows network speeds.

What is needed to make a LAN?

Networking equipment:

Hardware: at least two nodes

NIC - network interfacing card - wired or wireless

converts data signals from nodes into data signals that can be transferred across the network

Data transfer media: wires wireless technology

Wireless Access Point: add new nodes easily

general public can access if allowed

no building work needed

performance and security issues

Hub or Switch(if connected with wires)

Hub: connects nodes together. not intelligent-data is sent to all nodes across the whole network. cheap - useful in home installations.

Switch: connects nodes together. Intelligent-sends data to intended nodes.

Routers: manage data packets enabling them to be sent between networks. (e.g. over the internet)