1.3 - Network

• A network is two or more computers that are connected together for the purpose of communication. They are connected by a wired medium such as cables or wireless medium such as WI-FI.
• A stand-alone is a device that is not connected to a network.
• WI-FI is a method of connecting to the internet wirelessly using radio waves.
• The advantages of using networks is file sharing, hardware sharing, communication and roaming access.
• The advantages of using larger networks is centralised maintenance, centralised security, user monitoring and level of access.
• File sharing is the act of sharing files over the internet.
• A firewall is a type of software or hardware that stops unauthorised access to the network.
• Software is the programs, applications and data in a computer system.
• Hardware is the physical parts of a computers such as graphics card.
• The disadvantages of using a network is cost, management, spread of malware and hacking.
• Malware is the software that is designed to cause harm or damage to a computer.
• Hacking is gaining unauthorised access to data in a computer.
• A LAN is a network that is geographically confined to one building or site.
• A LAN operates on a single site such as a school, hotel or business using their own cabling system, hardware and infrastructure.
• The benefits of LAN is that it can share files, can work collaboratively, access their files from any computers, work together from different computers using instant message and centralised deployment of software to all computers.
• WAN are wide networks that is spread over a wide geographic area.
• WAN can cover more than one site, be spread across a country or the world. Communication is done through national telephone infrastructures or via wireless transmission.
• Internet is a global network connecting millions of computers.
• Network performance is about response time where it focuses on how fast a message can be sent or how quickly it can be retrieved.
• The performance of a network can be affected by the number of devices, bandwidth, type of network traffic, network latency and the number of transmission errors.
• Bandwidth is the amount of data that can be carried through a connection at a time.
• Connection speeds are measured in Mbps.
• The advantages of copper cables is tried and trusted technology and relatively inexpensive.
• The disadvantages of copper cable is that the signal is affected by electric and magnetic fields, low bandwidth and heavy cables.
• The advantages of fibre optics is that it has very fast transmission, low loss of signal over distance, not affected by magnetic or electric fields, requires little power and it is more difficult to tap in that copper cables.
• The disadvantages of fibre optics is that there is high investment cost, need for expensive optical transmitters and receivers.
• An advantage of wireless transmission is that there is no need for trailing wires, allows devices to be used anywhere provided and easier to add devices to a network.
• The disadvantages of wireless transmission is that data transmission rate is less than wired systems, signal can be blocked by objects or walls and increased security issues.
• Network latency is a measure of how long it takes a message to travel from one device to another across a network.
• A network with low latency experiences a few delays whereas a high latency network experiences many delays. The more delays the longer it takes to transmit data across a network.
• Latency is the length of time a packet of information takes to travel through the network.
• A hub is a piece of hardware used in computer networks to connect multiple devices.
• A switch is a device for connecting computers and other network capable devices together to form a network.
• Wired connection are more faster and reliable. The fibre optic cables can give much better performances than copper cables.
• Wireless depends on signal quality, the amount of interface from other wireless networks and physical obstructions.
• Interference causes errors which means signal needs retransmitting which makes more traffic, object may limit range and it can block the signal.
• Transmission is the sending of data from point A to point B.
• Traffic is communication sent over a network.
• Collision is the result of two devices on a network trying to communicate with each other.
• A client server is where the data or web application is hosted on a server and accessed by a client computers.