Summary
Highlights
Network hardware refers to physical devices essential for communication between other devices such as a personal computer to a printer. Key components include the Network Interface Card (NIC) for connecting to the internet via an Ethernet cable, network switches for secure and direct data transmission using MAC addresses, and routers for connecting multiple networks and forwarding data packets to the correct destinations. Wireless Access Points (WAPs) enable devices like laptops and phones to join a network. Common cabling types include Ethernet (copper wire, twisted pair for interference reduction), coaxial (single copper wire with metallic mesh for shielding), and fiber optic (light-based transmission for extreme speed, though expensive).
A client-server network is managed by a central server, which stores user profiles and files. Clients (devices) request data, and the server responds. Advantages include centralized file storage, easy access from any device, simplified software installation and updates, and customizable user access levels. Disadvantages are high setup costs, the need for an IT expert, and an increased risk of downtime if the server fails. A peer-to-peer network is server-less, with all devices being equal and able to store their own files. These are easy to set up, don't rely on a central server, and allow file sharing. However, they are less secure and if a device breaks, its files are not easily accessible from elsewhere.
Network topology refers to the layout of a network. The star topology uses a central switch or hub to which all devices are connected. Advantages include continued operation if one device fails, good performance due to minimal data collisions, and easy scalability. Disadvantages are high cost, the need for an expert to maintain, and complete network failure if the central device breaks. A mesh topology features fully connected devices with no central point of failure, allowing data to choose the fastest route. While it offers high resilience, it is expensive to set up due to extensive cabling unless a wireless mesh is implemented.
DNS translates memorable URLs (domain names) into numerical IP addresses, which are the actual location of a website on a web server. When a user enters a URL, the browser sends it to DNS, which then finds the corresponding IP address. If the IP is found, the web server sends the webpage data to the user. If not found, DNS will search higher-level DNS servers; if still unsuccessful, an error is returned. This process is analogous to a phone book, where you remember a name (URL) rather than a number (IP address).
Network standards are agreements for hardware and software compatibility, enabling different manufacturers' products to communicate. Examples include Ethernet, HTTP, and HTML. Devices on the same network communicate using unique MAC addresses, which are 12-character hexadecimal identifiers permanently assigned to each device. Devices on different networks communicate using IP addresses, which stand for Internet Protocol. IP addresses are not unique, can be changed, and are automatically allocated. IP version 6 offers a vast number of combinations allowing for wide network connectivity. An IP address must be assigned to a device before it can use the network.
Network protocols are sets of rules governing how devices communicate and transmit data across a network. Key protocols include: TCP/IP (Transmission Control Protocol/Internet Protocol) for reliable data packet delivery over the internet; HTTP/HTTPS (Hypertext Transfer Protocol/Secure) for web browsing, with HTTPS encrypting data; FTP (File Transfer Protocol) for moving files between devices; POP3 (Post Office Protocol 3) and IMAP (Internet Message Access Protocol) for email reception, with POP3 removing emails from the server and IMAP leaving copies; and SMTP (Simple Mail Transfer Protocol) for sending emails. The four-layer model (Application, Transport, Network, Link) simplifies network development by breaking down complex data transfer problems, allowing manufacturers to focus on specific layers and protocols, for example, the application layer uses HTTP for transferring data.
The 'cloud' encompasses file storage and services available over the internet such as cloud applications (e.g., Google Slides, Google Docs, Teams). Advantages include easy scalability of storage, external management of IT infrastructure by providers (saving businesses money), automatic security management and backups, continuous software updates, and ubiquitous access with an internet connection. Disadvantages include inaccessibility without an internet connection, potential vulnerability to hackers despite external security, and potentially expensive subscription fees for large storage or powerful applications.
A network consists of two or more connected devices used to share information and resources. Devices can include computers, laptops, and phones. Advantages of networks include easy file and hardware sharing (e.g., printers), user accounts for flexible access, and centralized software installation and updates. Disadvantages include the high cost of setup, the need for expert technicians, and the risk of viruses affecting multiple devices.
A Local Area Network (LAN) connects devices in a small geographical area, typically within one mile and on a single site. LANs can be wired or wireless and are common in schools and small businesses, with the organization owning the hardware. A Wide Area Network (WAN) connects devices over a large geographical area, exceeding one mile and across multiple sites. WANs often use satellite, radio, or telephone links, which are usually leased, inferring a higher cost due to that.
Network performance is influenced by bandwidth (the amount of data transferred in a given time), whether it's wired or wireless, wireless network interference, and the choice of hardware. High network traffic reduces performance. Wired networks are generally faster and more reliable than wireless ones, with technologies like fiber optic cables offering superior speed. Wireless networks are susceptible to physical obstructions like walls and limited range. The quality of hardware, such as choosing a network switch over a hub, significantly impacts speed and efficiency.