The term topology refers to the layout of connected devices on a network. The basics network topology are: bus, ring, star, tree and mesh. A bus network is so cold because each devices is net to the other in a linear shape. All devices are link by a backbone. A message is sent into wire and processes by the intended recipement. The easiest bus topology to instore are 10Base-2 or 10Base-5. The only advanteges of a bus network is that it is easy to install and cheap as it require only few cables but it has many disadvantages since perfomance is good only with limited number of cables. If the backbone fails the network is affected on the contrary if only one device fails nothing happens. A ring network is so-called because all devices are placed in a circular way. Messages travel through the ring only in one direction either clockwise or counterclockwise. The disadvantages is that if one device fails, the whole network takes don sonet or token ring technology are used. A star network is generally is caraterized by a central hub or a switch to each and all devices are connected it. The advantages is that if one devices fails, the all entwork is not affected, the disadvantages is taht it is quite expensive and difficolt to ensore bacause it require much cables. A treee topology integrates ultiple star topologies onto a bus. Its best main advantages is espansibility, on the other hand, it is expensive. As mesh topology involve the concpt of routers, messages can take several patch form sourse to destions. Many wans, such as the Ethernet, implove mouch rounting.