Curriculum Portal

neurologyYou need to know

• A Local Area Network (LAN) connects devices within a limited geographical area, such as a home, school or office, and is usually owned and managed by one organisation.
• A Wide Area Network (WAN) connects networks across a large geographical area using third-party telecommunications infrastructure; the Internet is the largest example.
• Network performance is affected by the available bandwidth, number of connected devices, transmission medium, network hardware, interference and the amount of data traffic.
• In a client-server network, clients request services and dedicated servers provide centralised services such as authentication, web pages, file storage and printing.
• In a peer-to-peer network, computers have equal status and can provide resources directly to one another without relying on a central server.
• A Network Interface Controller or Card (NIC) allows a device to connect to a network using a wired or wireless connection.
• A switch connects devices within a LAN and forwards data to the intended device, while a router connects different networks and directs data between them.
• A wireless access point allows wireless devices to join a network, while transmission media such as copper cable, fibre-optic cable and radio waves carry data between devices.
• The Internet is a worldwide collection of interconnected networks that communicate using common protocols.
• The Domain Name System (DNS) is a distributed system of Domain Name Servers that converts a domain name in a URL into the corresponding IP address.
• Web hosting stores a website's files on an Internet-connected web server, and a web client such as a browser requests and displays those files.
• Cloud computing provides remote services over a network, including storage, software and processing; it supports access from different locations but depends on connectivity and can create security, privacy, subscription-cost and provider-dependence risks.
• In a star topology, every device connects to a central switch or access point; it is easy to manage and a single cable failure affects only one device, but failure of the central device can stop the network.
• In a mesh topology, devices have multiple connections to other devices; this provides redundancy and reliability but requires more transmission media, ports, configuration and expense.
• Ethernet is a common wired connection that is usually fast, reliable and resistant to interference, whereas Wi-Fi allows mobility and easier installation but can suffer from interference, reduced range and security risks.
• Bluetooth is a wireless connection designed mainly for direct, short-range communication between devices and usually has lower range and bandwidth than Wi-Fi.
• Encryption converts plaintext into ciphertext using an algorithm and key so intercepted network data cannot be understood without the correct decryption key.
• An IPv4 address is a 32-bit address normally written as four decimal values from 0 to 255 separated by full stops, while an IPv6 address is a 128-bit address normally written as eight groups of hexadecimal digits separated by colons.
• A MAC address is a hardware identifier assigned to a network interface and used to identify devices within a local network; it is normally a 48-bit value written as six pairs of hexadecimal digits.
• A computing standard provides agreed rules that allow hardware and software from different manufacturers to interact, while a communication protocol provides rules for transferring data: TCP/IP supports reliable communication across networks, HTTP transfers web pages, HTTPS transfers encrypted web data, FTP transfers files, SMTP sends email, POP downloads email from a server, and IMAP manages email while retaining it on the server.

• Classify a network as a LAN or WAN from its geographical coverage, ownership and use of telecommunications infrastructure.
• Analyse how bandwidth, device numbers, traffic, transmission media, interference and hardware could affect network performance in a given scenario.
• Identify the function of a NIC, switch, router, wireless access point and transmission medium in a network diagram or description.
• Compare client-server and peer-to-peer networks, linking their structures to centralised management, security, cost, reliability and resource sharing.
• Recommend wired Ethernet, Wi-Fi or Bluetooth for a scenario by considering speed, range, mobility, reliability, interference, security and installation requirements.
• Select and justify a star or mesh topology for a scenario using reliability, fault tolerance, cost, cabling and ease of management.
• Trace the process of accessing a website from entering a URL, through DNS resolution and routing, to the browser requesting data from the web server.
• Recognise valid IPv4, IPv6 and MAC address formats and distinguish their roles in identifying network interfaces locally and routing data between networks.
• Select the appropriate protocol for web access, secure web access, file transfer, sending email or retrieving email, and justify the choice from its purpose.
• Explain how protocol layers divide communication into separate tasks, with each layer providing services to another, enabling easier development, replacement, troubleshooting and compatibility.