Computer Networks Tutorial
Network models, the physical and data-link layers, IP addressing and subnetting, routing, TCP/UDP and application protocols.
A computer network is a set of interconnected devices (nodes) that share resources and exchange data over communication links.
Types of Networks
| Type | Coverage | Example |
|---|---|---|
| PAN | ~10 m | Bluetooth headset |
| LAN | Building or campus | College lab Ethernet |
| MAN | City | Cable TV network |
| WAN | Country or global | The Internet |
Network Topologies
| Topology | Pros | Cons |
|---|---|---|
| Bus | Cheap, easy | A single cable fault brings the network down |
| Star | Easy to manage; one link failing doesn't affect others | Hub/switch is a single point of failure |
| Ring | Orderly access (token) | A break disrupts the ring |
| Mesh | Highly reliable; n(n−1)/2 links | Expensive cabling |
| Tree / Hybrid | Scalable | Complex |
Network Devices
| Device | OSI layer | Function |
|---|---|---|
| Repeater / Hub | Physical | Regenerates or broadcasts signals |
| Bridge / Switch | Data link | Forwards frames by MAC address |
| Router | Network | Forwards packets by IP address between networks |
| Gateway | All layers | Connects different protocol architectures |
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