computer science-networks

• Management of computer networks requires technical staff such as a network manager.
• Computer networks can be a vector for the spread of malware, which can cause harm or damage to a computer.
• A disadvantage of computer networks is the cost of additional equipment needed to allow computers to communicate.
• Roaming access in a computer network allows users to sign in to any computer on the network and access their files.
• Hacking is the unauthorised access to data in a computer network.
• Larger networks, such as those used by businesses and schools, offer additional benefits including centralised maintenance and updates, centralised security, and user monitoring.
• A network is a group of interconnected computers or devices.
• Encryption is used to ensure that messages can be sent securely over a network.
• Users can share files over the internet using file sharing.
• Computer networks bring a number of benefits, including file sharing, hardware sharing, and communication via email.
• Users can share hardware, such as a printer, over a network.
• Users can communicate via email over a network.
• The physical parts of a computer system, such as a graphics card, hard disk drive or CD drive, are referred to as hardware.
• Networks can be arranged in different topologies.
• Local area networks (LANs) are networks that cover a small area, such as a school or college.
• Wide area networks (WANs) are networks that span across a building, buildings or even countries, such as the internet.
• Encryption is used to ensure that messages can be sent securely over a network.
• There are two classifications of network: close network and wide network.
• A close network is a group of interconnected computers/devices, such as local area networks (LANs) and wide area networks (WANs).
• A wide network is a network that spans across a building, buildings or even countries, such as the internet.
• A LAN is a network that is geographically confined to one building or site, examples include networks employed by small businesses, small organisations, schools, colleges, universities and in homes.
• LANs are owned and maintained by the organisation.
• A wide area network (WAN) is a network that is spread over a wide geographical area, it can cover more than one site, or be spread across a country, or even the world.
• Organisations that have more than one office or branch, such as banks, tend to use a WAN.
• The WAN allows the head office to communicate and share data with the sub-offices and branches.
• Communication is done through national telephone infrastructures or via wireless transmission.
• Each office or branch has its own LAN that is connected together using the WAN.
• The internet is a global network connecting millions of computers, essentially a huge, international WAN.
• Encryption is used to ensure that messages can be sent securely over a network.
• Networks can be arranged in different topologies.
• Network performance is about response time - how fast a message can be sent or how quickly a document can be retrieved.
• The performance of a network can be affected by various factors: the number of devices on the network, bandwidth, network traffic, network latency, and number of transmissions.
• Bandwidth is a measure of the amount of data that can transfer through a communications channel over a given period of time.
• Data is often acted on by instructions.
• Each transmission medium has a different bandwidth: Medium Twisted copper wire Typical bandwidth Up to 10 gigabits (Gb) per second Medium Fibre-optic cable Typical bandwidth Up to 100 gigabits (Gb) per second Medium Wi-Fi (home networks) Typical bandwidth Up to 600 megabits (Mb) per second Medium Business Wi-Fi Typical bandwidth Up to 6 gigabits per second
• Each connected device requires bandwidth to be able to communicate.
• The bandwidth of the medium is shared between each connected device.
• For example, a home Wi-Fi network with one device would allocate 54 Mb per second to that device.
• If a second device joins the network, the bandwidth would be split between the two, giving 27 Mb per second to each, and so on.
• Network latency is a measure of how long it takes a message to travel from one device to another across a network.