The physical layer, the lowest layer of the OSI model, is concerned with the transmission and reception of the unstructured raw bit stream more than a physical medium. Packet switching could be used internally by backbone networks to take benefit of these traffic patterns, even although the backbone network could present a circuit-switching look to external hosts (see virtual circuit ). Traffic-pattern analysis may well be used to construct backbone networks that lessen specific network parameters, such as typical delay, circuit costs, etc.

First the ethernet address have to be translated into an ATM virtual circuit identifier for the circuit that leads from the edge switch to the edge switch nearest the location. Given its position at the top of the network hierarchy, two needs of the backbone topology are clear: it have to be reliable and it will have to scale. Gateways connect two or much more LANs that … Continue reading >>>