Data and Voice network topology, synthesis, and network-realization

The logical layout of the cable and devices that connect the nodes of the network is called topology. Network designers consider several factors in deciding which topology or combination of topologies to use. Different types of network topologies that are used for local area network are described as below:

Bus topology

A bus topology network uses one cable. All the nodes and peripheral devices are connected in a series of that cable. Special device, called terminator, is attached at the cable's start and end points, to stop network signals so they do not bounce back down the cable.

The advantage of this topology is that it uses the least amount of cabling of any topology. In a burst of only network, however, extra circuitry and software are used to keep data packets from colliding with one another. A broken connection can bring down all or part of the network.

Star topology

The start apology is probably the most common topology. In a star network, all nodes are connected to a device called a hub and communicate through it got data packets travel through the hub and are sent to the attached nodes, eventually reaching their destinations. Some hubs known as intelligent hubs can monitor traffic and help in preventing collisions. In a star topology, a broken connection between a node and the hub doesn't affect the rest of the network. If the hub is lost, however, all nodes connected to that hub are unable to communicate.

Ring topology

The ring topology connects the network's nodes in a circular chain, with each node connected to the next. The last node connects to the first, and completing the ring. Each node examines data as it travels through the ring. If the data known as a token is not the addressed to the node examining it, that node passes it to the next node. There is no danger of collisions because only one packet of data travels the ring at a time. If the ring is broken, however, the entire network is unable to communicate.

Mesh topology

The mesh topology is the least used network topology and the most expensive to implement. In a mesh environment, a cable runs from every computer to other computer. If you have four computers, you must have six cables-three coming from each computer to the other computer. The big advantage of this arrangement is that data can never fail to be delivered; if one connection goes down, there are other ways to route the data to its destination.