The Online is a international system of interconnected laptop or computer networks that use the common Online protocol suite (often called TCP/IP, despite the fact that not all protocols use TCP) to serve billions of customers worldwide. This kind of switched backbone is shown graphically in Figure 8.7. This has the benefit of putting all network gear in one particular location for simple maintenance and upgrade, but it does need far more cable. Most backbone topologies are, for that reason, initially designed primarily based on monetary constraints, such as user population density, or application needs and WAN service availability.
Translating protocols typically demands a lot more processing than encapsulation, so encapsulation can improve overall performance if the backbone devices are the bottleneck. This figure implies that the LAN switches are close to the computer systems in their LANs and farther from the backbone switch. This image is of the NSFNET T1 backbone and the volume of visitors going more than that network backbone for the month of September 1991.
First the ethernet address should be translated into an ATM virtual circuit identifier for the circuit that leads from the edge switch to the edge switch nearest the destination. Provided its position at the prime of the network hierarchy, two needs of the backbone topology are clear: it ought to be trusted and it should scale. Gateways connect two or extra LANs that use the same or unique (ordinarily distinctive) data link and network protocols.
Nations that have fully liberalized the marketplace for backbone networks have observed rapid growth in infrastructure competition. These architectures are routed backbones (routers that move packets on the basis of network layer addresses), switched backbones (switches that move packets primarily based on data hyperlink layer addresses), and virtual LANs (switches that move packets through LANs that are built practically, not utilizing physical place). FDDI and ATM need the translation or encapsulation of ethernet and token ring packets prior to they can flow by means of the backbone.
For this explanation, gigabit ethernet could stay mostly a backbone technology for use only in point-to-point full duplex data communications hyperlinks. Asynchronous Transfer Mode (ATM) (a.k.a. cell relay) is a technologies initially designed for use in wide location networks that is now generally utilized in backbone networks. It could also be called an enterprise network if it connects all networks inside a firm.