Network Topology is the specific physical, logical, or virtual, arrangement of the network components and devices (nodes). Network topology is determined only by the configuration of connections between nodes. Distances between nodes, physical interconnections, transmission rates, and/or signal types are not effects in a network topology. The common types of network topology are described below.

Bus topology or Linear Topology: All nodes on the LAN are connected by one linear cable, which is called the shared medium. Every node on this cable segment sees transmissions from every other station on the same segment. At each end of the bus is a terminator, which absorbs any signal, removing it from the bus. This medium cable apparently is the single point of failure. Ethernet (IEEE 802.3) is the protocols used for this type of LAN.

Mesh topology: Devices are connected with many redundant interconnections between network nodes such as routers and switches. In a mesh topology if any cable or node fails, there are many other ways for two nodes to communicate. Full mesh topology occurs when every node has a circuit connecting it to every other node in a network. Partial mesh topology where some nodes are organized in a full mesh scheme but others are only connected to one or two in the network, is often used in real network to provide the reliability with less complexity.

Ring topology: Every network node has two branches connected to it and form a ring. If one of the nodes on the ring fails than the ring is broken and cannot work. A dual ring topology has four branches connected to it, and is more resistant to failures.

Star topology: The network nodes are connected to a central node, which rebroadcasts all transmissions received from any peripheral node to all peripheral nodes on the network, including the originating node. All peripheral nodes may thus communicate with all others by transmitting to, and receiving from, the central node only.

Tree topology: The network nodes are arranged as a tree, which resembles an interconnection of star networks in that individual peripheral nodes are required to transmit to and receive from one other node only and are not required to act as repeaters or regenerators. Unlike the star network, the function of the central node may be distributed.

A hybrid topology is a combination of any two or more network topologies in such a way that the resulting network does not have one of the standard forms. For example, a tree network connected to a tree network is still a tree network, but two star networks connected together exhibit hybrid network topologies. A hybrid topology is always produced when two different basic network topologies are connected.

Network Topologies Overview

Related Terms: Bus Topology, Mesh Topology, Tree Topology, Ring Topology, Dual Ring Topology, Star Topology, Hybrid topology