IB Compsci Topic 3

Network: group of computer systems linked together to communicate and share resources
Local Area Network (LAN) - Home
Wide Area Network (WAN) - INTERNET, distance
Virtual Local Area Network (VLAN) - software defined
Wireless Local Area Network (WLAN)
Storage Area Network (SAN)
Personal Area Network (PAN) - bluetooth
Peer-to-Peer (P2P) - like Airdrop
Virtual Private Network (VPN)
Intranet (inside org) vs. Extranet (outside org)
Network Topologies: Bus, Ring, Star, Mesh (Internet)

Common language or rules = compatibility

OSI Model - 7 layers; be able to name the layers
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer

Encryption & Tunneling

Advantages: VPNs allow you to work anywhere remotely – telecommuting, Bypass Geoblocks, Keep you anonymous on the Internet, Avoid Price Discrimination
Disadvantages: Often slower, Is the telecommuter expected to work more hours as they are “at home” all day, Is everyone being anonymous on the internet a good thing? Hackers, Illegal Trade etc

Protocol - Sets of established rules that dictate how to format, transmit and receive data so computer network devices (e.g. servers, routers, and endpoints) can communicate regardless of the differences in their underlying infrastructures, designs or standards.
Data Packet - A block of data transmitted across a network.

Without a common set of rules computers would not be able to communicate.
Examples: data integrity, flow control, deadlock, congestion, error checking

Factors: Transmission Type (Wifi, Ethernet Cable etc), Cable Quality, Time of day, Speeds from the provider (Including Throttling), Distance, Network Infrastructure and equipment, and temperature, surrounding buildings, Interference also play a part.

Enables information to be disseminated faster.
Less data to send. Modifies file to reduce data.
Types: lossless, lossy

Guided (twisted pair, fiber optic) vs. Unguided (wifi)
Considerations: efficiency (speed), security, and cost

broken into a number of parts that are sent independently; can travel across different paths

Advantages: Easy to set up (no cabling required), Can be installed almost anywhere (no need to drill holes etc.), Allows mobility, Easy to add new devices to network, cheap to set up, Global standards (eg.802.11n), Uses unlicensed radio spectrum
Disadvantages: Traffic through network can be intercepted by unauthorised people, Slow transmission speeds, Interference from other wireless stations, cables reducing speed, Signal range depends on participating devices' antenna

Software: Network Operating System (with drivers), Protocol stack (TCP/IP), Applications
Hardware: Node: PC, Laptop, Printer, Wireless network interface card, Radio waves (Bluetooth/WiFi), Connection point: Wireless AP / Router

Know the Types: Wifi, WiMax, 3G, 4G, 5G

Methods: authentication, endpoint security, firewall, prevent physical access, encryption (WEP, WPA, WPA2), turn off wifi, don’t broadcast SSID, permit by MAC address

Authentication - limit access; passwords stolen
Encryption - hides data, backdoors
MAC Address - extra security, time consuming
Review slides for more detail