Topology in networking refers to the arrangement of devices (nodes) and connections (links) within a computer network. It describes both the physical layout—how hardware like routers, switches, and computers are physically connected—and the logical structure, which is how data actually flows between those devices, regardless of their physical placement.
Physical vs. Logical Topology
• Physical topology: The actual physical layout of cables, devices, and other network components. This is what you would see if you looked at the network hardware itself—where cables run, where devices are placed, and how they are interconnected.
• Logical topology: The conceptual path that data follows through the network, which may differ from the physical connections. Logical topology defines how data moves between devices and how the network appears to operate from a data transmission perspective.
Common Network Topologies
Network topology refers to the arrangement of different elements (links, nodes, etc.) in a computer network. The main types of network topologies are:
- Point-to-Point Topology
• The simplest topology, connecting two nodes directly with a dedicated link.
• Used for direct device-to-device communication, such as between two computers or switches. - Bus Topology
• All devices are connected to a single central cable (the bus).
• Data sent by one device is available to all, but only the intended recipient processes it.
• Advantages: Simple, cost-effective, requires less cabling.
• Disadvantages: The central cable is a single point of failure; performance degrades as more devices are added. - Ring Topology
• Each device connects to exactly two other devices, forming a closed loop.
• Data travels in one direction (or both, in a dual ring).
• Advantages: Predictable performance, no data collisions.
• Disadvantages: Any break in the ring can disrupt the entire network.
- Star Topology
• All nodes connect to a central hub or switch.
• The hub acts as a repeater for data flow.
• Advantages: Easy to add/remove devices, failure in one node doesn’t affect others.
• Disadvantages: The central hub is a single point of failure; requires more cabling than bus or ring. - Tree Topology
• A hierarchical structure combining multiple star topologies onto a bus.
• Often used in large organizations and campuses.
• Advantages: Scalable, easy to manage.
• Disadvantages: Dependent on the main bus cable; complex setup. - Mesh Topology
• Every device is connected to every other device (full mesh) or to some devices (partial mesh).
• Provides high redundancy and reliability.
• Advantages: Fault-tolerant, robust.
• Disadvantages: Expensive, complex to set up and maintain due to the number of connections required. - Hybrid Topology
• Combines two or more different topologies (e.g., star-bus, star-ring).
• Used to leverage the strengths and minimize the weaknesses of basic topologies.
• Highly adaptable to organizational needs. - Daisy Chain Topology
• Devices are connected in series, one after another.
• Can form a linear chain or a ring if the ends are connected.
• Used in simple or legacy networks.