Networks and the effects of using them

• Networks are usually described as a type of area network.
• The most common types of networks are LAN, WAN, WLAN, and PAN.
• LAN (local area network) enables a group of computers that are in close proximity to each other to be networked.
• LAN is typically used in school, office, or home.
• WAN ( wide area network) normally connects LANs together to cover larger geographic areas.
• The internet is and example of WAN .
• A WAN will connect cities a country or many countries.
• WAN: a wide area network consist of two or more LANs which are geographically separated and are linked by telephone lines or radio waves.
• WLAN: a wireles local area network covers short distances, using radio or infrared signals.
• WLAN overs short distances, it connects wirelessly using radio or infra red signals instead of the method of network cabling.
• wifi is an example of WAN.
• An example of LAN is a school or office network.
• PAN (personal area network) is a wireless network that connects devices within a small area.
• Bluetooth is an example of PAN
• Router is a device that provides a link between two or more networks.
• Router: a device that is used to forward data packets along networks, it will select the best route for each data packet so that data travels as quickly as possible to its destination.
• Routers work together to direct data packets to their correct destination.
• A router allows to join 2 dissimilar networks
• An internet protocol data packet should include packet identification details, source address, destination address and data.
• A router works by 1. decides if the destination of the address for a packet is on the LAN or outside it, it gets the address from the field in the packet header; 2. If the destination is on a WAN or the internet, the router uses its internal routing table to choose the best route for the packet; 3. each packet travels separately by the best available route; 4. Upon arrival the packets are reassembled into the original message.
• Network devices are the hardware components that connect computers and other devices together in a network.
• The most common devices to set up a LAN are a hup or a switch, a router, cabling, wifi technology, network cards and a modem.
• Each computer on a network needs a network interface controller (NCI) to provide the hardware interface between the computers and the network, which can be wired or wireless.
• NIC can be provided by a separated network interface card, thought newer computers come with an Ethernet NIC already build into the motherboard.
• For wireless networks, the NIC provides radio communication to the network access point.
• Modem: changes or modulates digital data sent from a computer into analog waves so that it may travel along telephone lines.
• The modem at the receiving end changes or demodulates the analogue data back into a digital form that the receiving computer can understand.
• Ethernet: the most common standard defining the wiring and signaling in LAN.
• WiFI: wireless network technology that allows communication via radio waves to connect devices to a local area network, which can then allow them to connect to the internet.
• A hub and a switch are where a network has central point to which all the signals from individual computers are sent. The cables from all the computers are plugged into this device.
• If a computer needs to send a signal to another computer on the network, the signal is sent to the hub or switch.
• A hub will broadcast the data to all the connected devices including the computer that sends the signal, this creates a lot of needless network traffic. The message will be send to all the devices on the network, but only the device for which it was intended will accept it.
• A switch has the same function of a hub but hadles messages more intelligently.
• A switch inspects the address of the device to which they should be sent. It only sent the message to the correct device.
• bridges: is the device that allos to dissimilar networks to send messages from one to an other.
• A bridge can only connect networks if they use the same rules for handling messages.
• The bridge can change the form of a message so that it is suitable for a different type of network.
• Modems are used to connect a computer or a network to the internet.
• A modem changes the digital signals from the computer into an analoge one called modulating that can be transmitted down telephone lines..
• A wireless router enables you to set up a Wireless local area network(WLAN).