module 4: networking computing notes by niq

󾠱 module 4: networking 4.1: concepts 4.1.1: computer networks 4.1.2 difference between wired and wireless transmission media 4.1.3 LAN vs WAN 4.1.4: client-server and peer-to-peer network architectures 4.1.5: star and mesh topologies 4.1.68: protocols and error detection network protocol: detecting errors in packet transmission 4.2 home networks and the internet 4.2.2: modems 4.2.3 NIC, network switches, WAP, routers 4.2.45 MAC vs IPv4 vs IPv6 media access control MAC) address: IP addresses: IPv4 and IPv6 4.2.6 Connect a router, a switch and a wireless access point to a modem correctly 4.3 security and privacy 4.3.1: differentiating security and privacy 4.3.2: how human actions threaten security and privacy 4.3.3: anti-malware 4.3.4: firewalls 4.3.5: encryption 4.3.6 PDPA 4.3.7: adware 4.3.8: spyware module 4: networking 1

4.1: concepts 4.1.1: computer networks 💡a computer network is a system of two or more devices that are connected by a transmission medium for the exchange of data 4.1.2 difference between wired and wireless transmission media wired networks: a network of devices connected by physical cables, typically using ethernet wireless networks: a network of devices in which signals are transmitted without the use of physical cables, typically using wi-fi factor wired wireless cost initially cheaper but becomes more expensive as network grows due to cost of cables initially expensive due to the cost of wireless networking hardware but becomes more cost-effective as network grows speed of transmission and bandwidth faster and higher bandwidth as cables provide dedicated connection generally slower and lower bandwidth due to possuble interference from radiowaves or microwaves; varies according to user location 4.3.9: cookies 4.3.10: phishing 4.3.11: pharming 4.3.12: good computing practices 4.3.13: analysis of security and privacy defences against threats module 4: networking 2

factor wired wireless reliability more reliable as data transmission is less affected by interference less reliable due to potential interference from radiowaves and microwaves or blockage from physical obstructions security more secure as the network is less susceptible to interception and hacking from a distance less secure due to possible intrusions by hackers who do not need physical access to cable or hardware mobility of users lower as network connections are fixed at specific spots and users cannot move to other locations higher as users can move about freely within the range of the wireless network scalability more cumbersome to add new devices to the network due to the need for additional cables easier to add new devices to the network as no additional hardware is usually needed; however there is a limit as interference increases with the number of wireless devices physical organisation tends to look more disorganised due to cables running across floors more organised without cables 4.1.3 LAN vs WAN local area network LAN network of computing devices connected within a small geographical area, typically within the same building such as home, school, office due to small number of connections supported and the proximity of devices, LANs typically provide faster data transfer than larger network like WANs module 4: networking 3

home networks are examples of LANs 4.2 wide area network WAN network of computing devices covering a large-scale geographical area, typically across multiple geographical locations unlike a LAN, a WAN is not limited to just one location and can span long distances can be either private or public, private ones can be built with encryption, allowing for confidentiality can consists of multiple LANs the internet is an example of a WAN that is formed by connecting many different LANs from around the world together 4.2 4.1.4: client-server and peer-to-peer network architectures client: device that initiates a connection to request for resources and services to perform operations (eg students use their devices as clients to do their work) server: device that shares resources and responds to requests from devices and other servers on the network, usually has a higher capacity and is more powerful than a client feature client-server peer-to-peer function data and resources shared using one or more dedicated servers, each device has a distinct role: client or server data and resources are shared directly between devices, each device acts as both a client and server organisation of hardware each client is connected to one or more dedicated servers each device in the network can serve as a client and server at the same time bandwidth typically high as servers have centralised control to use bandwidth more efficiently and offer varies depending on how data needs to be transmitted; bandwidth may be reduced if a single device handles module 4: networking 4

feature client-server peer-to-peer more reliable connections, however this relies on the capabilities of the server many large requests, can be increased if large requests are divided into smaller requests that are handled by multiple devices simultaneously security high as rights can be controlled centrally at a server low as security is handled by each device and not by a centralised device (server) setup cost high as the use of specialised high- performance servers would be needed low as basic devices can act as servers to share resources storage centralised and usually managed at the server by a network administrator decentralised and usually managed by individual users at each device application found in businesses or organisations with many users found in homes or small businesses where there are fewer users 4.1.5: star and mesh topologies star topology: network hardware such as a switch or wireless access point is at the centre of the network with connections to all the other devices mesh topology: devices are connected to each other fully-connected mesh network: every device directly connected to every other device partially-connected mesh network: some devices connected to several others but not to all module 4: networking 5

factor star topology mesh topology applications in home networks suitable for both wired and wireless networks typically only suitable for wireless home networks, especially home automation complexity less complex more complex cost typically lower cost depending on medium, only one piece of central network hardware is needed (but rlly depends on whether itʼs wired or wireless) typically higher cost; more network hardware needed robustness (resilience) less robust as the central hardware is a single point of failure that will stop the entire network if it fails more robust as typically there would be multiple different routes between devices, and the network would continue to function if any one device or hardware fails range typically smaller; limited by cable length and distance to the central hardware typically larger; each addition of network hardware extends the networkʼs range without sacrificing speed standards highly standardised so hardware from different companies can usually work together currently not highly standardised so hardware from different companies may not work together- 4.1.6-8: protocols and error detection network protocol: a set of standards and rules that govern how two or more devices communicate over a network module 4: networking 6

LANs typically use protocols where data is transmitted as individual packets packets: units of broken data containing a header with information that i sneeded for transmission, such as the source and destination addresses packet numbers: a number in a packetʼs header that indicates the position of that packet in the sequence of data being transmitted detecting errors in packet transmission parity (eg. for a byte 00001111 parity check: an error-checking technique which uses a parity bit to detect errors in an even parity bit system: total number of 1-bits (including parity bit) should be even 0000011