The Internet backbone refers to the principal data routes between large,
strategically interconnected 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 interchange Internet traffic between the
countries, continents and across the oceans of the world. Internet
service providers (often Tier 1 networks) participate in Internet
backbone exchange traffic by privately negotiated interconnection
agreements, primarily governed by the principle of settlement-free
The Internet backbone is a conglomeration of multiple, redundant
networks owned by numerous companies. It is typically a fiber optic
trunk line. The trunk line consists of many fiber optic cables bundled
together to increase the capacity. The backbone is able to reroute
traffic in case of a failure. The data speeds of backbone lines have
changed with the times. In 1998, all of the United States backbone
networks had utilized the slowest data rate of 45 Mbit/s. However the
changing technologies allowed for 41 percent of backbones to have data
rates of 2,488 Mbit/s or faster by the mid 2000s. Fiber-optic cables are
the medium of choice for Internet backbone providers for many reasons.
Fiber-optics allow for fast data speeds and large bandwidth; they suffer
relatively little attenuation, allowing them to cover long distances
with few repeaters; they are also immune to crosstalk and other forms of
Electromagnetic interference which plague electrical transmission.
Because of the enormous overlap between long-distance telephone networks
and backbone networks, the largest long-distance voice carriers such as
AT&T Inc., MCI, Sprint, and CenturyLink also own some of the largest
Internet backbone networks. These backbone providers sell their services
to Internet service providers (ISPs).
Each ISP has its own contingency network and is equipped with an
outsourced backup. These networks are intertwined and crisscrossed to
create a redundant network. Many companies operate their own backbones,
that are all interconnected at various Internet exchange points (IXPs)
around the world. In order for data to navigate this web, it is
necessary to have backbone routers, which are routers powerful enough to
handle information on the Internet backbone and are capable of directing
data to other routers in order to send it to its final destination.
Without them, information would be lost because data does not know how
to locate its end destination.
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