Network topology is the description of how a network is physically laid out and how signals travel from one device to another device. However, the physical layout of devices does not thoroughly describe how signals travel from one device to another, so network topologies are put into the physical or logical categories. The physical topology of a network is the geometric layout of workstations (Tomsho, 2011). The common physical topologies are bus, star, ring, point-to-point, and mesh (Tomsho, 2011). Although logical topology is how data travels from computer to computer. In other words, logical topology reveals the underlying network technology used to transfer information from one device to another device.
Bus networks are an arrangement of local area network (LAN) in which each node connects or links to the main cable (TechTarget, 2000-2012). Bus networks are reliable and simple to operate because if one fails the others can still communicate with each other. So for total failure to occur in a bus network the bus must break down. Also bus networks are easy to expand nodes can be added at anytime and anywhere. However, bus networks do have length limits because of possible cable loss. The bus networks do not work well if nodes are randomly put at various points that do not lie near a common line.
Advantages of Bus Topology * Easy computer connection. * Minimum cable length. * It is the cheapest.
Disadvantages of Bus Topology * The entire network goes down if even one cable breaks. * The backbone cables require terminators at each end. * Problem identification is difficult when entire network is down. * Not recommended for large stand-alone organization solution. * Includes reconnection and fault isolation. * Management of the network is high. * Backbone will require modification or replacement if additional devices are added.
Star networks are an arrangement of local area network (LAN) in which nodes connect or link directly to a common central computer (TechTarget, 2000-2012). So each computer connects indirectly to every other computer by way of the central computer. Star networks operate well when nodes are randomly put at various points on a common line, and this makes it easy to add or remove devices. In the event a star network cable failure occurs, the computer links to the central computer will go into isolation. Fortunately, that is the only computer that will be in isolation, other computers will function normal except they will not be able to communicate with the isolated computer. So if any computer were to shut down the other computers will not be affected. Nevertheless, if the central computer shuts down the entire network will as well.
Advantages of a Star Topology * Easy installation. * No disruptions during connection or removal of devices. * Easy detection and part removal. * Not as expensive. * Link failure does not affect all links only the broken link.
Disadvantages of a Star Topology * System dies when hub failure occurs. * Nodes are not active if the hub, switch, or concentrator fails. * Requires more cable length. * More expensive because of the cost of the hubs, etc.
Ring networks are an arrangement of local area network (LAN) in which nodes connect or link through a closed loop configuration (TechTarget, 2000-2012). So adjacent pairs of nodes connect directly, and other pairs of nodes connect indirectly. The information will pass through one or more intermediate nodes. Ring topology reigns supreme when system requirements are modest and devices are at scattered points. So if devices are close to the highest point of a convex polygon, the cost will decrease in regard to other topologies when cable routes lessen the length of time the cable is necessary. If cable failure occurs in ring networks data speed will be lower between pairs of devices in which data paths will increase because of