Fortunately, nobody
owns the Internet, there is no centralized control, and nobody can
turn it off. Its evolution depends on rough
consensus about technical proposals, and on running code.
Engineering feed-back from real implementations is more important
than any architectural principles
RFC
1958; B. Carpenter;
Architectural Principles of the Internet; June, 1996. |
The Internet is by definition a
meta-network, a constantly changing collection of thousands of individual
networks
intercommunicating
with a common protocol.
The Internet's architecture is described in its name, a short
from of the compound word "inter-networking". This architecture is
based in the very specification of the standard TCP/IP protocol,
designed to connect any two networks which
may be very different in internal hardware, software, and technical design.
Once two networks are interconnected, communication with TCP/IP is enabled
end-to-end,
so that any node
on the
Internet has the near magical ability to communicate with any
other
no matter
where they are. This openness of design has enabled the Internet
architecture to grow to a global scale.
In practice, the Internet technical architecture looks a bit like a multi-dimensional
river system, with small tributaries feeding
medium-sized streams feeding large rivers.
For example, an individual's access
to the Internet is often from home over a modem
to a local Internet service provider
who connects to a regional network connected to a national network. At
the office, a desktop computer might be connected to a local area network
with a company connection to a corporate Intranet connected to several national
Internet service providers. In general, small local Internet service providers
connect to medium-sized regional networks which connect to large national
networks,
which
then connect
to very large bandwidth networks on the Internet backbone.
Most Internet service providers have several redundant
network cross-connections to other providers in order to ensure continuous
availability.
The companies running the Internet backbone operate very high bandwidth
networks relied on by governments, corporations, large organizations,
and other Internet service providers. Their technical infrastructure often
includes global connections through underwater cables and satellite links
to enable communication between countries and continents. As always, a larger
scale introduces new phenomena: the number of packets flowing through the switches
on
the backbone is so large that it exhibits the kind of complex non-linear
patterns usually found in natural, analog systems like the flow of water
or development of the rings of Saturn (RFC
3439, S2.2).
Each communication packet goes
up the hierarchy of Internet networks as far as necessary to get to its
destination network where local routing takes
over to deliver it to the addressee. In the same way, each level in
the hierarchy
pays the next level for the bandwidth they use, and then the large backbone
companies settle up with each other. Bandwidth is priced by large
Internet service providers
by several methods, such as
at a fixed rate for constant availability of a certain
number of megabits per second, or by a variety of use methods that amount
to a cost per gigabyte. Due to economies of scale and efficiencies in management,
bandwidth cost drops dramatically at the higher levels of the architecture.
Resources. The network topology page
provides information and resources on the real-time construction of the Internet
network, including graphs and statistics. The
following references
provide additional information
about
the
Internet architecture:
-
RFC
3426; S. Floyd; General Architectural and Policy Considerations;
Nov 2002
-
RFC
3439; R. Bush, D. Meyer; Some Internet Architectural Guidelines
and Philosophy; Dec 2002
- RFC
3819; P. Karn, Ed.; Advice
for Internet Subnetwork Designers; July 2004
- RFC 3945; E. Mannie, Ed.; Generalized Multi-Protocol Label Switching
(GMPLS) Architecture; October 2004
