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What is a network? • Networks consist of a group of two or more computers linked together to share resources. With a network you can share files, allow electronic communications etc. A network might be linked through cables, telephone lines, radio waves, satellites or infrared light beams.
Stand alone • Stand alone devices are devices that function individually and they don’t need any other devices or machines to function.
LAN • A Local Area Network (LAN) is a networks that connects computer limited to a small area, such as a home, school or office building.
WAN • A Wide Area Network (WAN) is a telecommunication network that can cover a broad area unlike LAN which is limited to a small area. WAN can be linked across national boundaries.
Client Networks • The user uses an application made by a server. The servers are often on different computers accessed by a network.
Server Networks • A networks server is a computer that shares resources to workstations and other servers on a network. The resources can include email services, hardware access etc.
Client Server Network • This is a network where one centralized server is a hub to clients. The clients run programs and access data that are stored on the server.
Peer to Peer Network • A Peer-To-Peer network consist of personal computers, they act both as a client and a server. So they can exchange files and emails directly.
Advantages of LAN • Very easy to share devices such as printers, scanners etc. • Easy to share data such as pictures, movies etc. • The cost of a LAN setup is very low. • Users can communicate with each other and transfer data easily.
Disadvantages of LAN • Limited area covered. • Hard to set up and might need to be maintained by skilled technicians. • If something goes wrong in the network users might lose the data. • If the network is big, its harder to manage.
Cabled LAN • A cabled LAN is when the network is connected through cables instead of the wireless connections. • There is three different types of cables: Coaxial cable, Optical fiber cable and Twisted pair cable.
LAN • Hardware required to connect to a LAN: Ethernet cable, Network router, hub or switch and a Network Interface Card (NIC).
LAN Topologies. • LANs always use a form of physical layout designs, the designs are called topologies.
Ring Topology • Ring topologies transmit in one direction, only from station to station. Ring topologies uses separate physical ports and wires for transmit and receive.
Bus Topology • Bus topologies shares a physical connection for communication, the media is shared between stations. If one station transmits on the bus, all devices hear the transmission.
Hub and Spoke (Star) Topology • Hub and spoke topologies use a central hub connection point, multiple devices are connected to this hub. You can also use a switch or a router instead of a hub.
Advantages of bus topology. • Easy to connect computers to a linear bus. • Requires less cable length than star topology
Advantages of Star Topology • Easy to install and wire. • If connecting or removing devices there will be no disruptions. • Easy to find/detect fault and remove part if needed.
Disadvantages of a Star Topology • Requires more cable length than linear topology. • If the concentrator, hub or switch fails, nodes attached are disabled. • More expensive than bus topologies because of the hubs etc.
Wireless LAN. • A Wireless Local Area Network (WLAN) is a LAN that doesn’t rely on wired Ethernet connections, it can either be an extension to a current wired network or an alternative. • A WLAN signal can cover bigger areas such as small offices or a large campus. • Because the wireless signal is broadcasted to everyone in the area, passwords is a security precaution to ensure only authorized access.
WAN • A Wide Area Network (WAN) is a telecommunication network that can cover a broad area unlike LAN which is limited to a small area. • WAN can be linked across national boundaries, so they are often connected through public networks, such as the telephone system. • The largest WAN in existence is the internet. • Transmission rates are typically 2 Mbps, 34 Mbps, 45 Mbps, 155 Mbps, 625 Mbps, but it can be more. • Many international companies such as hotels, airline companies etc. use this.
Data transmission • Data transmission means the transportation of information from one place to another, this can be any kind whatsoever. • Data transmission sends streams of bits or bytes from one location to another, such as copper wire, fiber optics, lasers , radio or infrared light.
Data transmission: Email • Email is a very popular form of data transfer because its free, however not secure. • The data transmissions through email is very limited because the file size available for transmission is limited.
Data transmission: Bandwidth. • Bandwidth is often used as a synonym for data transfer rate. The speed of the bandwidth is usually measured in in megabits per second (Mbs) .
Data transmission: Narrowband • The term Narrowband is used to describe an internet connection speed. Narrowband is usually connected to the internet via phone lines. • Narrowband internet speed is five times slower than the slowest broadband available, so this connection is almost useless now.
Data transmission: Broadband • Broadband usually refers to a high-speed internet access that is always on, its always faster than a dial-up access. • This is the most used connection to the internet because of its high access speed. You can access it in four different forms, DSL, fiber-optic cable, satellite and the old dial-up connection.
