Computer Networks
A computer network is a system that connects multiple computers and electronic devices together. The primary purpose of this connection is to share resources (like printers or internet access), exchange information, and facilitate communication.
Networks are broadly classified based on their geographical scale and specific functionality. For competitive examinations, it is important to understand the hierarchy and core purpose of each network type.
Networks Based on Geographical Scale
The following networks are listed in order of increasing geographical size:
1. Personal Area Network (PAN):
- This is the smallest type of network, designed for an individual’s workspace.
- It typically connects personal devices like smartphones, wireless headphones, and laptops over a short range of about 10 meters.
- PANs primarily use technologies like Bluetooth or USB.
2. Home Area Network (HAN):
- Operational strictly within a single residence, a HAN connects various digital devices to facilitate resource sharing among family members.
- It forms the foundation for modern smart homes (connecting smart TVs, smart speakers, and security cameras).
3. Local Area Network (LAN):
- A LAN connects computers within a limited geographical area, such as a single office building, a school, or a hospital.
- LANs offer very high data transfer rates and are commonly built using Ethernet cables or Wi-Fi
4. Campus Area Network (CAN):
- A CAN connects multiple LANs within a specific, concentrated geographical area, such as a university campus or a large corporate headquarters.
- It is larger than a LAN but smaller than a MAN
5. Metropolitan Area Network (MAN):
- A MAN operates within a city. It provides high-speed connectivity by linking several LANs across a metropolitan region.
- A classic example of a MAN is a city-wide cable TV network.
6. Wide Area Network (WAN):
- A WAN covers massive geographic areas, spanning across cities, countries, or continents.
- Because it covers long distances, a WAN generally has lower data transfer rates compared to a LAN.
- The Internet is the largest and most famous example of a WAN.
7. Global Area Network (GAN):
- A GAN covers a global scale and operates without geographical boundaries.
- It heavily utilizes satellite communication and international undersea fibre-optic cables to connect WANs worldwide.
Specialized Networks
These networks are categorized by their specific functions rather than their physical size:
8. Storage Area Network (SAN):
- Unlike a standard network that connects user computers, a SAN is a highly specialized, high-speed network dedicated solely to connecting servers to data storage devices (like disk arrays).
- It enables efficient, bulk data storage and retrieval.
- It commonly uses advanced technologies like Fibre Channel or iSCSI.
9. Virtual Private Network (VPN):
- A VPN is not a physical network. Instead, it creates a secure, encrypted tunnel over a public network (like the internet).
- It allows users to send and receive data as if their devices were directly connected to a private network.
- VPNs are highly crucial for secure communication, remote office work, and protecting user privacy from untrusted public networks.
