Definition: A network is a group of interconnected devices that can communicate and share resources with each other.
Core Components
- Host / End Device: Every computer on a network.
- Server: Computers that provide information to end devices.
Email servers, web servers, file servers.
- Client: Computers that send requests to servers to retrieve information.
- Intermediary Device: Hardware that interconnects end devices.
Switches, routers, firewalls, wireless access points.
Transmission Media
Communication is carried through a specific medium using different signal types:
| Medium | Signal Type |
|---|---|
| Metal Wires (Cables) | Electrical Impulses |
| Fiber Optics (Glass/Plastic) | Pulses of Light |
| Wireless | Electromagnetic Waves |
Network Architecture
The Internet is essentially a worldwide collection of interconnected LANs and WANs. A robust network architecture relies on four pillars:
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Fault Tolerance: The ability to recover quickly when a failure occurs.
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Scalability: The ability to grow without degrading performance.
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Quality of Service (QoS): Managing priorities (e.g., voice vs. data), often handled by routers.
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Security: Protecting the confidentiality, integrity, and availability of data.
Packet Switching
Concept: Traffic is split into small “packets” that are routed independently over the network.
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Routing: Each packet can take a different path to the destination.
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Redundancy: Reliable networks use packet switching to ensure that if one path fails, packets can automatically reroute.