Overview

Network topology describes the arrangement of links and devices that form a computer network. It covers both the physical layout of cables, wireless links and hardware and the logical paths that data follow. Physical and logical topologies may differ: a set of devices laid out physically in a circle can implement a logical star, for example. Topology is a fundamental concept in designing networks because it affects performance, fault tolerance, cost and scalability.

Main types

  • Bus: A single shared medium to which devices attach. Simple and inexpensive, but limited by collisions and scale.
  • Star: Each device connects to a central hub or switch. Common in homes and offices because failures are often isolated to a single link.
  • Ring: Devices form a closed loop where each node connects to two neighbors. Data circulates in one or two directions; some ring systems use token passing to control access.
  • Mesh: Multiple interconnections between devices, offering redundancy and high availability. Full mesh connects every node to every other; partial mesh connects key nodes.
  • Tree (hierarchical): A branching structure that combines star or bus segments into a layered layout used in larger networks.
  • Hybrid: Combinations of the above to meet specific technical or economic needs.

Characteristics and design considerations

When choosing a topology engineers balance throughput, latency, reliability, cost and ease of expansion. Mesh topologies provide resilience but increase cabling and complexity. Star and tree designs simplify management but concentrate failure risk at central devices. The choice also interacts with protocols and devices; for example, modern switched Ethernet behaves logically like a collection of point-to-point links even when cabling appears as a star.

History and development

Early network experiments and telephone systems shaped common topologies. Local area network technologies explored different models—shared-medium bus systems, token-based rings, and later switched fabrics—each influencing where topology was most useful. More recently, data center fabrics, virtualization and software-defined networking have introduced overlay topologies where virtual links map onto physical infrastructure.

Uses, examples and important distinctions

Topologies are chosen according to use cases: small home and office networks usually adopt star configurations for simplicity, campus and enterprise networks apply hierarchical tree designs, and critical infrastructure or backbone networks may use mesh structures for redundancy. It is important to distinguish physical topology (actual cables and wireless links) from logical topology (the path that frames or packets follow) and to remember that the same physical arrangement can support multiple logical topologies depending on protocols and devices. For more foundational terms see nodes and related glossary entries.