G063 3.3.3

3.3.3 a

• Candidates should be able to, in general and within the context of a scenario, be able to compare the characteristics of a local area network (LAN), a wide area network (WAN) and a virtual network.
• LAN
• A LAN has two or more machines connected in a geographically close area. It could be in one business building and still cover a nearby university, hospital etc. Each machine is connected to a "hub/switch" that is at the centre of all of them. Characteristics:
• LAN usually have peripherals that can be shared, such as printers.
• LAN's are designed for the sharing of data and files.
• LAN's allow applications to be run directly from a server.
• WAN
• A WAN allows diversely dispersed computers to be connected. A WAN can span the world in terms of range. A router/modem often connects machines to this network.
• Virtual Network
• A virtual network is "real", as it moves data between computers. But it is a smaller version of a LAN/WAN where only specific computers can interact with eachother. Think about computers in a school. Some are used by students, some by teachers. Teacher computers can interact with each other, student computers can interact with each other.

3.3.3 b

• Candidates should be able to compare the characteristics and purpose of intra nets, the internet and extranets.
• Intranet - an Intranet is a private system that only authorized members can see. They have similar characteristics as the internet, as it uses IP protocol to allows computers to connect with each other. It's virtually the same as the internet, but for internal use only.
• Extranet - an extranet is one where people from outside the organisation can connect to the internal Intranet. For example, mobile phone companies set up extranets so their customers can connect wherever they are. These nets are not directly connected to any LAN/WAN systems but are still able to establish a connection with the correct equipment and authorization.
• Internet - a vast communication network that spans the globe and connects millions of machines. It uses a protocol called TCIP/IP. It is simply a "network of networks". Businesses and organizations own their own network, which is thus connected to millions of other networks.

3.3.3 c

• Candidates should be able to describe client-server and peer-to-peer networks.
• Client server - a powerful computer known as a server provides all the connections and services required on a network. It manages all the relevant peripherals. The "client" part is the machines that people log onto that are connected to the server.
• Peer to peer - in this configuration there is no central server. Instead, each
• workstation is loaded with the appropriate applications needed for that
• machine and local resources such as an attached printer folder or
• external hard drive can be shared. This type of network is commonly found in homes and small offices. Every machine on the network is independent.

3.3.3 d

• Candidates should be able to explain the importance of bandwidth when transmitting data and analyse how different types of communication media (cables, wireless, optical) govern the bandwidth available (knowledge of examples of different communication media is expected.
• Bandwidth - Any communication channel has to be able to transmit information from
• one location to another. The method might be analogue such as radio or
• it might be digital such as a computer network. Bandwidth is a measure that quantifies the capability of a communication channel to transmit information. The reason that bandwidth is so important is that it determines what you can do in terms of real-time services. If the bandwidth is too low for such services, then the only option is
• to download the complete audio or video file then play it back offline.
• More information here:
• http://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/333_networks_coms/bandwidth/miniweb/index.htm

3.3.3 e

• Candidates should be able to compare the role of the following network components: switches, hubs, wireless access points, network interface cards, wireless network interface cards, routers, repeaters, gateways, firewalls and servers (file, application, mail proxy, print, backup) and justify where their use would be appropriate.
• This is an extensive section of 3.3.3 - read through this and take any relevant notes in your study.
• http://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/333_networks_coms/network_components/miniweb/inde...
• http://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/333_networks_coms/servers/miniweb/index.htm

3.3.3 f

• Candidates should be able to describe optical communication methods (infrared, fibre optic, laser), their advantages, disadvantages and typical applications.
• Infrared - this is one of the earliest types of optical communication and is still
• very much in use today. It is found in remote controls for televisions,
• dvd players and most other entertainment devices. Infrared uses light that is invisible to us and is just above the red end of the colour spectrum. An LED emits the light. It is an inexpensive method, but only works at short range.
• Fibre optic - the widest bandwith available comes from fibre optic. The tech is based around transparent glass fibre. It's an expensive method, but can carry signals over much longer distances.
• Laser - this uses high power laser beams to emit signals. For example, setting up a high bandwidth data link between two
• line-of-sight buildings can make use of a free-space laser system. They can be used in:
• campuses
• emergency data links
• satellite to satellite

3.3.3 g

• Candidates should be able to describe wireless communication methods, their advantages, disadvantages and typical applications.
• Bluetooth - this is developed for radio transimission of data over short ranges. It uses a tiny radio signal to emit its data, and is found in all mobile phones. Bluetooth devices pick eachother up automatically because they operate off of a network. Bluetooth is used in:
• hands-free calls
• short ranged communication between machines
• transferring data between devices
• Wireless communication (WiFi) - this makes use of radio waves to emit data. Wi-Fi is widely used for LANs and WANs as it does not need any cabling
• to be laid down. It does need a device called a Wireless Access Point or
• WAP to be present on the network to handle the radio traffic. WAPs are
• commonly called 'hotspots' and can be found in airports, stations,
• cafes, library and other public spaces.

3.3.3 h

• Candidates should be able to describe the facilities of the following communication applications: fax, email, bulletin boards, tele/video conferencing and instant messaging and compare their use for a given task.
• This is an extensive section of 3.3.3 - read through this and take any relevant notes in your study.
• http://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/333_networks_coms/communication_applications/mini...

3.3.3 i

• Candidates should be able to discuss the use and implications of social networking.
• This is an extensive section of 3.3.3 - read through this and take any relevant notes in your study.
• http://www.teach-ict.com/as_a2_ict_new/ocr/A2_G063/333_networks_coms/broadband_connections/miniweb/i...