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The Internet backbone refers to the main 'trunk' connections of the Internet. It is made up of a large collection of interconnected commercial, government, academic and other high-capacity data routes and core routers that carry data across the countries, continents and oceans of the world.

Part of the extreme resilience of the Internet is due to a high level of redundancy in the Internet backbone and the fact that the Internet Protocol routing decisions are made and updated in real-time during use.

Contents 1 History 2 Overview 3 See also 4 External links

The original Internet backbone was the ARPANET.

In 1989 the NSFNet backbone was established, the US military broke off as a separate MILNET network, and the ARPANET was shut down.

A plan was then developed for expanding NSFNet further, prior to rendering it obsolete by creating a new network architecture based on decentralized routing.

With the decommissioning of the NSFNet Internet backbone network on April 30, 1995, the Internet now consists entirely of the various commercial ISPs and private networks (as well as inter-university networks), as connected at their peering points.

The term "Internet backbone" is now sometimes loosely used to refer to the inter-provider links and peering points. However, with the universal use of the BGP routing protocol, the Internet functions with no single central network at all.

With the advent of the dot-com bust of 2002, a number of major telecommunications carriers were threatened by bankruptcy, and some failed completely: for example, the EBONE network was decommissioned in its entirety. This was a successful test of the level of fault-tolerance and redundancy of the Internet.

The Internet backbone consists of many different networks. Usually, the term is used to describe large networks that interconnect with each other and may have individual ISPs as clients. For example, a local ISP may provide service for a single town, and connect to a regional provider which has several local ISPs as clients. This regional provider connects to one of the backbone networks, which provides nationwide or worldwide connections.

These backbone providers usually provide connection facilities in many cities for their clients, and they themselves connect with other backbone providers at Internet Exchange Point (IXP)s such as MAE-East in the eastern United States or FreeIX in France. The largest of these IXP's in terms of both throughput and connected peers is the Amsterdam Internet Exchange.

Backbone networks are usually commercial, educational, or government owned, such as military networks. Some large companies that provide backbone connectivity include UUnet (now a division of Verizon), British Telecom, AT&T, Sprint Nextel, France Télécom, Reliance Communications, VSNL, BSNL, HE.NET, Teleglobe (now a division of VSNL International), Flag Telecom (now a division of Reliance Communications), Qwest, Level 3 Communications, and SAVVIS.

• Peering
• Trunking
• Switching
• Routing
• Backbone network
• Network service provider
• Root nameserver

• Russ Haynal's ISP Page
• Internet backbone maps
• BT Infonet, Internet backbone network maps
• Information Aesthetics, Internet backbone map
• Cybertelecom :: Federal Internet Backbone Policy
• Automatically generated backbone map of the Internet