Network topology refers to the physical or logical layout of devices in a computer network. It defines how computers, switches, routers, and other devices are connected and how data flows between them. Choosing the right topology is important because it affects network performance, reliability, and scalability.
Let’s understand the most commonly used network topologies with clear explanations and real-world examples.
1. Star Topology
Definition
In a star topology, all devices are connected to a central device such as a switch or hub. Every piece of data passes through this central point.
Real-World Examples
- Home Wi-Fi network connected through a router
- Office networks using switches
- School computer labs
Advantages
- Easy to install and manage
- Failure of one device does not affect others
- Easy to add new devices
Disadvantages
- If the central switch fails, the entire network goes down
Most modern LANs use star topology.
2. Ring Topology
Definition
In a ring topology, each device is connected to exactly two other devices, forming a circular loop. Data travels in one direction around the ring.
Real-World Examples
- Older LAN technologies (Token Ring)
- Industrial and manufacturing systems
Advantages
- Equal access to network resources
- No data collisions
Disadvantages
- Failure of one device or cable can break the network
- Difficult to troubleshoot
3. Bus Topology
Definition
In a bus topology, all devices share a single communication cable called the backbone. Data is sent in both directions.
Real-World Examples
- Early Ethernet networks
- Small temporary networks
Advantages
- Easy to install
- Requires less cable
Disadvantages
- Network performance degrades with more devices
- If the main cable fails, the entire network stops
4. Mesh Topology
Definition
In a mesh topology, each device is connected to multiple or all other devices. This creates multiple paths for data transmission.
Real-World Examples
- Internet backbone networks
- Military and banking systems
- Wireless mesh networks
Advantages
- High reliability and fault tolerance
- No single point of failure
Disadvantages
- Expensive
- Complex to install and maintain
Quick Comparison Table
| Topology | Structure | Reliability | Cost | Usage |
|---|---|---|---|---|
| Star | Central device | High | Medium | Homes, offices |
| Ring | Circular | Medium | Medium | Legacy systems |
| Bus | Single backbone | Low | Low | Small networks |
| Mesh | Multiple connections | Very High | High | Critical networks |
Why Network Topologies Matter in CCNA
Understanding network topologies helps CCNA students learn:
- Network design principles
- Troubleshooting techniques
- Performance optimization
- Scalability planning
These concepts form the foundation for routing, switching, and network architecture.