Networks continued Revision Notes

A router is a critical device that connects multiple networks, such as linking a home or office network to the internet. It stores the addresses of connected devices and networks, enabling it to direct data packets efficiently to their correct destinations. For example, when you send an email, the router determines the best path for the data to travel across networks to reach the recipient's device. Routers manage traffic to prevent data collisions and ensure smooth communication between devices and external networks.

• Connects different networks and devices to the internet.
• Stores IP addresses to identify devices and networks.
• Routes data packets by selecting optimal paths.

Several devices facilitate network communication, each with specific roles: Network Interface Cards (NICs) are hardware components inside devices that allow them to connect to a network, either wired or wireless. Hubs act as simple repeaters, broadcasting incoming data to all connected devices, which can cause unnecessary traffic. Bridges connect two separate network segments, filtering traffic to reduce congestion. Switches are more advanced than hubs; they send data only to the intended recipient device by using MAC addresses, improving network efficiency.

• NICs enable device connection to networks.
• Hubs broadcast data to all devices, causing potential traffic.
• Bridges connect and filter between two network segments.
• Switches direct data to specific devices, reducing unnecessary traffic.

Wi-Fi and Bluetooth are wireless technologies that allow devices to connect without cables but serve different purposes. Wi-Fi provides wireless internet access over moderate distances, typically within a building or campus, supporting multiple devices simultaneously. Bluetooth connects devices over short distances, usually up to 10 metres, and is ideal for linking peripherals like headphones or keyboards to a computer or phone. While Wi-Fi is designed for network access and internet connectivity, Bluetooth focuses on direct device-to-device communication with lower power consumption.

• Wi-Fi offers wireless internet access over longer ranges (up to 100 metres indoors).
• Bluetooth connects devices over short ranges (around 10 metres).
• Wi-Fi supports multiple devices on a network; Bluetooth connects devices in pairs or small groups.
• Wi-Fi consumes more power; Bluetooth is energy-efficient for peripheral connections.

Cloud computing enables storage, management, and processing of data and applications on remote servers accessed via the internet. This allows users to access files and software from any device with internet connectivity, facilitating collaboration and data sharing. For example, using cloud storage services like Google Drive lets multiple users edit documents simultaneously. However, cloud computing raises concerns about data security, privacy, and reliance on internet availability. Compared to local storage, cloud storage offers scalability and remote access but may expose data to external risks and requires trust in service providers.

• Stores and manages data on remote servers accessible online.
• Enables easy sharing and remote access to data and applications.
• Offers scalability and reduces need for local storage hardware.
• Raises security and privacy concerns due to data being stored externally.
• Depends on reliable internet connection for access.

An intranet is a private network restricted to an organisation’s internal users, used for sharing information and resources securely within the company. An extranet extends part of the intranet to authorised external users, such as suppliers or partners, allowing controlled access to specific data. The internet is a global public network accessible to anyone, connecting millions of private and public networks worldwide. For example, a company’s intranet might host internal documents, while an extranet allows suppliers to check order status, and the internet provides public websites.

• Intranet: private network for internal organisational use.
• Extranet: private network accessible to authorised external users.
• Internet: public global network connecting millions of networks.
• Access control and security vary among these environments.

A Local Area Network (LAN) connects devices within a limited area such as a home, school, or office building, typically using wired connections. A Wireless Local Area Network (WLAN) is similar but uses wireless technology like Wi-Fi to connect devices without cables. A Wide Area Network (WAN) covers a large geographical area, connecting multiple LANs or WLANs, often through leased telecommunication lines or the internet. For example, a university campus may have a LAN for each building, a WLAN for wireless access, and a WAN connecting campuses across cities.

• LAN: wired network covering a small area, e.g., an office.
• WLAN: wireless version of LAN using Wi-Fi technology.
• WAN: network spanning large geographical areas, connecting multiple LANs/WLANs.
• WANs often use public or leased communication lines.