| Network topology refers to the physical layout of | | | | computers to the central location where they are |
| the network i.e. the locations of the computers | | | | all connected by a device called hub or switch. |
| and how the cable is run between them. To | | | | Each computer on a star network communicates |
| select the right topology for how the network will | | | | with a central device that resends the message |
| be used is very important. Each topology has its | | | | either to each computer or only to the destination |
| own strength and weaknesses. | | | | computer, e.g. if it is a hub then it will send to all |
| The choice of a topology for installing a computer | | | | and if it is a switch then it will send to only |
| network depends upon a combination of factors | | | | destination computer.When network expansion is |
| such as, reliability, performance of the system, | | | | expected and when the greater reliability is |
| number of nodes and geographical distribution of | | | | needed, star topology is the best. |
| the system. | | | | Advantages: |
| The main 2 types are | | | | 1) It is easy to modify and add new computers |
| Bus Topology & Peer to Peer Topology | | | | without disturbing the rest of the network. |
| Peer to Peer topology consists of Star topology | | | | 2) The center of the star network is a good |
| and Ring topology. | | | | place to diagnose the faults. |
| Bus Topology | | | | 3) Single computer failure does not necessarily |
| It is often used when network installation is small, | | | | bring down the whole star network. |
| simple or temporary. On a typical bus network | | | | Disadvantages: |
| the cable is just 1 or more wires with no active | | | | 1) If the central device fails the whole network |
| electronics to amplify the signal or pass it along | | | | fails to operate. |
| from computer to computer. This makes the bus | | | | 2) Star networking is expensive because all |
| a passive topology. When 1 computer send a | | | | network cables must be pulled to one central |
| signal up the wire all the computers receive the | | | | point, requires more cable than other network |
| information but only one with the address that | | | | topologies. |
| matches accepts the information, the rest | | | | Ring Topology |
| disregard the message. | | | | In this type each computer is connected to the |
| Advantages: | | | | next computer with the last one connected to |
| 1) Easy to use and to understand. | | | | the first. Each retransmits what it receives from |
| 2) Requires least amount of cable to connect the | | | | the previous computer. The message flows |
| computers together. It is therefore less | | | | around the ring in one direction. The ring network |
| expensive than other cabling arrangements. | | | | does not subject to signal loss problem as a bus |
| 3) It is easy to extend a bus; two cables can be | | | | network experiences. There is no termination |
| joined into 1 longer cable with a BNC, Barrel | | | | because there is no end to the ring. |
| connector making a longer cable and allowing | | | | Advantages: |
| more computers to join the network. | | | | 1) Each node has equal access. |
| Disadvantages: | | | | 2) Capable of high speed data transfer. |
| 1) Heavy network traffic can slow a bus | | | | Disadvantages: |
| considerably as only 1 computer can send a | | | | 1) Failure of one computer on the ring can affect |
| message at a time. | | | | the whole network. |
| 2) It is difficult to troubleshoot the bus. A cable | | | | 2) Difficult to troubleshoot the network. |
| break or loose connector causes reflection and | | | | Topologies remain an essential part of network |
| stops all the activity. | | | | design speculation. But understanding these can |
| Star Topology | | | | help you to get the deeper knowledge of the |
| In this kind of topology all the cables run from the | | | | elements like hub, switch etc. |