Unit:2 Network Topology and Types

2.1 Definition of Topology

Network topology is the physical or logical arrangement of computers and devices in a network and how they are connected to communicate with each other.

Example: In a computer lab, if all computers connect to one switch, the connection structure is called a topology.

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2.2 Types of Topologies

Topologies are mainly divided into:

1. Wired Topology
2. Wireless Topology

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2.2.1 Wired Topologies

These use cables (Ethernet, fiber optic, etc.) for communication.

1. BUS Topology

All computers are connected to a single main cable (backbone).

Diagram:

PC ─── PC ─── PC ─── PC
        Main Cable

Example: Small office network.

Advantages:

• Low cost
• Easy installation

Disadvantage:

• If main cable fails, whole network stops

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2. Star Topology

All computers connect to a central device (Switch/Hub).

Diagram:

        PC
         |
PC ---- Switch ---- PC
         |
        PC

Example: School computer labs, offices.

Advantages:

• Easy management
• Failure of one computer does not affect others

Disadvantage:

• If switch fails, network stops

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3. Ring Topology

Computers connect in a circular form.

Diagram:

PC ---- PC
|        |
|        |
PC ---- PC

Example: Older token ring networks.

Advantages:

• Data flows in an organized way

Disadvantage:

• One failure may affect entire network

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4. Hybrid Topology

Combination of two or more topologies.

Diagram:

      Switch
     /      \
   PC        PC
     \      /
      BUS Network

Example: Large organizations and universities.

Advantages:

• Flexible
• Scalable

Disadvantage:

• Complex and expensive

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5. Mesh Topology

Every computer connects to all other computers.

Diagram:

PC1 ------ PC2
 |\        /|
 | \      / |
 |  \    /  |
 |   \  /   |
PC3 ------ PC4

Example: Internet backbone, military networks.

Advantages:

• Highly reliable
• Multiple paths available

Disadvantage:

• Expensive

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2.2.2 Wireless Topologies

These use wireless signals instead of cables.

1. Wi-Fi

Uses radio signals for short-distance communication.

Example:

• Home Wi-Fi
• School Wi-Fi

Diagram:

      📶 Router
      /   |   \
   Phone Laptop PC

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2. Satellite

Uses satellites in space for communication.

Example:

• TV broadcasting
• GPS systems

Diagram:

Ground Station ↑
                🛰
                 ↓
            Users

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3. Radio Wave

Uses radio frequencies to send data.

Example:

• FM radio
• Walkie-talkies
• Mobile communication

Diagram:

Tower ))))) Phone

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