Backbone network

A backbone or core network is a part of a computer network which interconnects networks, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than the networks connected to it. A large corporation that has many locations may have a backbone network that ties all of the locations together, for example, if a server cluster needs to be accessed by different departments of a company that are located at different geographical locations. The pieces of the network connections (for example: Ethernet, wireless) that bring these departments together is often mentioned as network backbone. Network congestion is often taken into consideration while designing backbones. One example of a backbone network is the Internet backbone. The theory, design principles, and first instantiation of the backbone network came from the telephone core network when traffic was purely voice. The core network was the central part of a telecommunications network that provided various services to customers who were connected by the access network. One of the main functions was to route telephone calls across the PSTN. Typically the term referred to the high capacity communication facilities that connect primary nodes. A core network provided paths for the exchange of information between different sub-networks. In the United States, local exchange core networks were linked by several competing interexchange networks; in the rest of the world, the core network has been extended to national boundaries. Core networks usually had a mesh topology that provided any-to-any connections among devices on the network. Many main service providers would have their own core/backbone networks that are interconnected. Some large enterprises have their own core/backbone network, which are typically connected to the public networks.