What is Network topology

Network topology is the arrangement of various elements of a computer network such as screen projectors, routers and printers, which can be depicted physically or logically.

Types of Network Topology 

Physical topology includes the placement of various components of a network, like the cabling layout.

Logical topology, on the other hand, refers to the path of data within the network. It is the way, signals act on a networked media. For example, in LAN network, any given node in the network will be connected to one or more other nodes. With the aid of graphical mapping technique, geometric shapes can be brought out from mapping these links. Similarly, mapping the data flow between these computers can help us see the logical topography of the network.

Basic topology patterns include point-to-point, bus, star, ring or circular, mesh, tree and hybrid.

Point to point topology involves a dedicated link between two end points. More or less like a child’s tin telephone, it uses circuit switching or packet switching technologies. This allows seamless communication over the network.

In bus topology, each node is connected to a single cable called ‘bus. A message from the source travels in both directions through the bus, until it finds the target recipient. The message will be ignored by all other machines, other than the targeted one. It is an economical step, since it involves a single cable. The downside to bus topology is that any problem with bus can lead to total shut down of the system.

When each network host is connected point to point to a central hub, the topology to opt for is star. Here, it is not mandatory that the network should resemble a star, but all the nodes have to be connected to a single central device. The central hub acts like a message repeater and each message is passed through the central hub. It is easy in its designing and implementation. The biggest advantage of star is its ease to add additional nodes and its advantage is that the hub can be the single point of failure.

A ring is a modified bus, designed into a closed loop.  The data transmitted, goes through each node, on its way till it reaches its destination. All these intermediate nodes, repeat the data so as to keep the signal strong. With no hierarchical order, each node does the same function.  It functions better than bus, when the load of the network increases. But, the entire data will be cut off, if a single node fails to repeat the signal.

Mesh topology is also a kind of point to point connection to other nodes. It can either be partial or full. In a fully connected network, all the nodes are connected to each other, whereas the partially connected network on the other hand will not have all the nodes interconnected. Here, certain nodes will be connected to exactly one other node and certain other nodes are connected to two or more other nodes with a point-to-point link.

Hybrid network is the combination of two or more topology designs.  It need not resemble any other standard topology. For example, a tree network, which is a hybrid of bus topology and star topology.