Over the previous handful of years, there has been a big alter in the way we believe about LANs and backbone networks. Fiber channel is a switched technology like ATM, and like ATM, all circuits are full duplex and deliver numerous classes of service. LANs have traditionally applied multipoint circuits, and WANs have traditionally utilised point-to-point circuits.
Switched Backbones: most widespread variety of backbone, utilized in distribution layer, made use of in new buildings, in some cases in core layer, can be rack or chassis primarily based. Although website traffic engineering calculations and circumventing congestion are common in the telephone network, typical IP networks and their connected routing protocols do not offer this capability as readily. The FDDI-MAC scheme uses a variation of the IEEE 802.five token-passing regular used for token-ring networks with two types of tokens: absolutely free tokens and busy tokens.
A significant corporation that has several locations might have a backbone network that ties all of the locations collectively, for example, if a server cluster desires to be accessed by distinctive departments of a organization that are situated at unique geographical areas. The Internet has enabled or accelerated new forms of human interactions by way of immediate messaging, World-wide-web forums, and social networking. Distributed backbone permits very simple administration and management of the network due to its segregation. If higher-capacity backbone networks are to extend beyond these places, some form of public assistance will probably be needed.
Countries that have completely liberalized the marketplace for backbone networks have noticed speedy 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 based on information link layer addresses), and virtual LANs (switches that move packets through LANs that are built practically, not using physical location). FDDI and ATM call for the translation or encapsulation of ethernet and token ring packets prior to they can flow via the backbone.