Internet backbone

The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers on the Internet. These data routes are hosted by commercial, government, academic and other high-capacity network centers, the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents and across the oceans. Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering.

The first packet-switched computer network was the NPL network, followed closely by the ARPANET. The latter used a backbone of routers called Interface Message Processors. Both the NPL and ARPANET networks were interconnected in 1973, while other packet-switched computer networks began to proliferate in the 1970s, eventually adopting TCP/IP protocols or being replaced by newer networks. The National Science Foundation created NSFNET in 1986 by funding six networking sites using 56kbit/s interconnecting links and peering to the ARPANET. In 1987, this new network was upgraded to 1.5Mbit/s T1 links for thirteen sites. These sites included regional networks that in turn connected over 170 other networks. IBM, MCI and Merit upgraded the backbone to 45Mbit/s bandwidth (T3) in 1991. The combination of the ARPANET and NSFNET became known as the Internet. Within a few years, the dominance of the NSFNet backbone led to the decommissioning of the redundant ARPANET infrastructure in 1990.

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