Networking and topologies
Download full article
Industrial Communications Handbook
By Mick Crabtree
Chapter 2: Networking and topologies
The physical layout (or topology) of a network is usually implemented as one of four forms: Bus (or multi-drop), star, ring or mesh.
Bus: In bus topology, all nodes connect to a common media – often called the backbone.
Star: In the star topology, each node has its own network segment that links it back to a central host – called the hub – which controls all communications.
Ring (or loop): In ring topology, all the nodes are connected to a single cable that forms a closed loop or ring. Data flows only in one direction – with each node passing the data onto the next node on the line.
Tree: A tree topology combines the characteristics of star and bus topologies. In its simplest form, a hub connects directly to the bus – with each functioning as the root of a tree of devices.
Mesh: In a mesh network, each node is connected to several others and involves the concept of routes – such that a message can take any of several possible paths from source to destination.