Define Topology And Its types?

Long Questions

Question: Define Topology And Its types?      

 Ans: Topology:

                           A Network Topology is the pattern in which nodes (i.e., computers, printers, routers or other devices) are connected to a local area Network (LAN) or other Network via links (e.g., twisted pair copper wire cable or optical fiber cable). There are four principal Topology used in LAN: Bus, Ring, Star , Physical and Mesh.

Physical Topology:                                                                                                                                        
                                            The term physical topology refers to the way in which a network is laid out physically. Two or more devices connect to a link; two or more links form a topology. The topology of a network is the geometric representation of the relationship of all the links and linking devices (usually called nodes) to one another. There are four basic topology possible: mesh, star, bus, and ring.

Mesh Topology:                                                                                                                                            
                                      In a mesh topology, every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects. To find the  number of physical links in a fully connected mesh net- work with n nodes.

Star Topology:                                                                                                                               

                                   In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to one another. Unlike a mesh topology, a star topology does not allow direct traffic between devices. The controller acts as an exchange: If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device.

Bus Topology:                      
                                The preceding examples all describe point-to-point connections. A bus topology, on the other hand, is multi-point. One long cable acts as a backbone to link all the devices in a network.

Ring Topology:                                                                                                                                                                                        In a ring topology, each device has a dedicated point-to-point connection with only the two devices on either side of it. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along.