The Internet backbone was the main network ( computer network ) that connected every part of the internet. Nowadays this term is used as a free word to describe the "core " of the current Internet.
The original Internet backbone was the Arpanet. 1986 NSFNet backbone was established, the U.S. Army turned away as a separate MILNET network and the Arpanet was abolished. There, a plan was then developed to enhance the NSFN back bone before it was surpassed by the invention of a decentralized routing based on new network architecture, called the Network Access Point ( NAP). After the decommissioning of the NSFNET Internet backbone on 30 April 2005, there is now the Internet mainly from several commercial Internet service providers ( ISPs) and private networks. The term Internet backbone is now used mainly free to take on the links between providers and peering points on the reference.
The Internet backbone is composed of many different networks. Usually this term is used to refer to interconnected grids that have individual Internet Service Provider ( ISP) as clients. For example, a local ISP to serve a single city and be connected to a regional provider that owns several local ISPs. This regional provider is in turn connected to a backbone network, the country-or world connections provides.
These backbone providers offer their customers generally in many cities connecting devices, which in turn connect to other backbone providers through internet nodes.