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Internet & Network
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A commonly asked question is "What is the Internet?" The reason such a
question gets asked so often is because there's no-agreed-upon answer
that neatly sums up the Internet. The Internet can be thought about in
relation to its common protocols, as a physical collection of routers
and circuits, as a set of shared resources, or even as an attitude
about interconnecting and intercommunication. Some common definitions
given in the past include:
- a network of networks based on the TCP/IP protocols,
- a community of people who use and develop those networks, and
- a collection of resources that can be reached from those networks.
- TCP/IP = Transfer Control Protocol/Internet Protocol
Today's Internet is a global resource connecting millions of users that
began as an experiment obout 25 years ago by the U.S. Department of
Defense. While the networks that make up the Internet are based on a
standard set of protocols (a mutually agreed upon method of
communication between parties or Operating Systems), the Internet
also has gateways to networks and services that are based on other
proprietary protocols.
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The Internet - History & Background
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"The Creation of the Universe was made possible
by a grant from Texas Instruments"
- PBS Nova "The Creation of the Universe"
The Internet was born about 30 years ago, trying to connect together a
U.S. Defense Department network called the ARPAnet and various other
radio and satellite networks. The ARPAnet was an experimental network
designed to support military research - in particular, research about
how to build networks that could withstand partial outages (like bomb
attacks) and still function. (Think about this when you read section on
how the network works; it may give you some insight into the design of the
Internet.)
In the ARPAnet model, communication always occurs between a
source and a destination computer. The network itself is assumed to be
unreliable; any portion of the network could disappear at any moment
(pick your favorite catastrophe - these days, backhoes cutting cables are
more of a threat than bombs). Thus, ARPAnet was designed to require the minimum of
information from the computer clients. To send a message on the
network, a computer only had to put its data in an envelope, called an
Internet Protocol (IP) packet, and "address" the packets correctly. The
communicating computers--not the network itself--were also given the
responsibility to ensure that the communication was accomplished. The
philosophy was that every computer on the network could talk, as a
peer, with any other computer.
These decisions may sound odd, like the assumption of an "unreliable"
network, but history has proven that most of them were reasonably
correct. Although the Organization for International Standardization
(ISO) was spending years designing the ultimate standard for computer
networking, people could not wait. Internet developers in the US, UK
and Scandinavia, responding to market pressures, began to put their IP
software on every conceivable type of computer. It became the only
practical method for computers from different manufacturers to
communicate. This was attractive to the government and universities,
which didn't have policies saying that all computers must be bought
from the same vendor. Everyone bought whichever computer they liked,
and expected the computers to work together over the network.
At about the same time as the Internet was coming into being, Ethernet
Local Area Networks ("LANs") were developed. This technology matured
quietly, until desktop workstations became available around 1983. Most
of these workstations came with Berkeley UNIX, which included IP
networking software. This created a new demand: rather than connecting
to a single large timesharing computer per site, organizations wanted
to connect the ARPAnet to their entire local network. This would allow
all the computers on that LAN to access ARPAnet facilities. About the
same time, other organizations started building their own networks
using the same communications protocols as the ARPAnet: namely, IP and
its relatives. It became obvious that if these networks could talk
together, users on one network could communicate with those on another;
everyone would benefit.
One of the most important of these newer networks was the NSFNET,
commissioned by the National Science Foundation (NSF), an agency of the
U.S. government. In the late 80's the NSF created five supercomputer
centers. Up to this point, the world's fastest computers had only been
available to weapons developers and a few researchers from very large
corporations. By creating supercomputer centers, the NSF was making
these resources available for any scholarly research. Only five centers
were created because they were so expensive--so they had to be shared.
This created a communications problem: they needed a way to connect
their centers together and to allow the clients of these centers to
access them. At first, the NSF tried to use the ARPAnet for
communications, but this strategy failed because of bureaucracy and
staffing problems. (well, what else?)
In response, NSF decided to build its own network, based on the
ARPAnet's IP technology. It connected the centers with 56,000 bit per
second (56k bps) telephone lines. (This is roughly the ability to
transfer two full typewritten pages per second. That's slow by modern
standards, but was reasonably fast in the mid 80's.) It was obvious,
however, that if they tried to connect every university directly to a
supercomputing center, they would go broke. You pay for these telephone
lines by the mile. One line per campus with a supercomputing center at
the hub, like spokes on a bike wheel, adds up to lots of miles of phone
lines. Therefore, they decided to create regional networks. In each
area of the country, schools would be connected to their nearest
neighbor. Each chain was connected to a supercomputer center at one
point and the centers were connected together. With this configuration,
any computer could eventually communicate with any other by forwarding
the conversation through its neighbors.
This solution was successful--and, like any successful solution, a time
came when it no longer worked--simply the demand had overgrown. Sharing
supercomputers also allowed the connected sites to share a lot of other
things not related to the supercomputing centers. Suddenly these schools
had a world of data and collaborators at their fingertips. The network's
traffic increased until, eventually, the computers controlling the
network and the telephone lines connecting them were overloaded. In 1987,
a contract to manage and upgrade the network was awarded to Merit
Network Inc., which ran Michigan's educational network, in partnership
with IBM and MCI. The old network was replaced with faster telephone
lines (by a factor of 20), with faster computers to control it.
The process of running out of horsepower and getting bigger engines and
better roads continues to this day. Unlike changes to the highway
system, however, most of these changes aren't noticed by the people
trying to use the Internet to do real work. You won't go to your
office, log in to your computer, and find a message saying that the
Internet will be inaccessible for the next six months because of
improvements. Perhaps even more important: the process of running out
of capacity and improving the network has created a technology that's
extremely mature and practical. The ideas have been tested; problems
have appeared, and problems have been solved.
The single most important aspect of the NSF's networking
effort is that it allowed everyone to access the network. Up to that
point, Internet access had been available only to researchers in
computer science, government employees, and government contractors. The
NSF promoted universal educational access by funding campus connections
only if the campus had a plan to spread the access around. So everyone
attending a four year college could became an Internet user.
The demand keeps growing. Now that most four-year colleges are
connected, people are trying to get secondary and primary schools
connected. People who have graduated from college know what the
Internet is good for, and talk their employers into connecting
corporations. All this activity points to continued growth, networking
problems to solve, evolving technologies, and job security for
networkers.
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What Makes Up the Internet?
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What comprises the Internet is a difficult question; the answer changes
over time. A couple of years ago the answer would have been easy: "All the
networks, using the IP protocol, which cooperate to form a seamless
network for their collective users." This would include various federal
networks, a set of regional networks, campus networks, and some foreign
networks.
More recently, some non-IP-based networks saw that the Internet was
good. They wanted to provide its services to their clientele. So they
developed methods of connecting these "strange" networks (e.g., BITNET,
DECnets, etc.) to the Internet. At first these connections, called
"gateways", merely served to transfer electronic mail between the two
networks. Some, however, have grown to translate other services between
the networks as well. Are they part of the Internet? Maybe yes and
maybe no. It depends on whether, in their hearts, they want to be. If
this sounds strange, read on--it gets stranger.
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Who Governs the Internet?
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"You can build a throne with bayonets, but you can't sit on it for long"
- Boris Yeltsin
In many ways the Internet is like a church: it has its council of
elders, every member has an opinion about how things should work, and
you can either take part or not. It's your choice. The Internet has no
president, chief operating officer, or Pope in that regard.
The constituent networks
may have presidents and CEO's, but that's a different issue; there's no
single authority figure for the Internet as a whole.
The ultimate authority for where the Internet is going rests with the
Internet Society, or ISOC. ISOC is a voluntary membership organization
whose purpose is to promote global information exchange through
Internet technology. It appoints a
council of elders, which has responsibility for the technical
management and direction of the Internet.
The council of elders is a group of invited volunteers called the
Internet Architecture Board, or the IAB. The IAB meets regularly to
"bless" standards and allocate resources, like addresses. The Internet
works because there are standard ways for computers and software
applications to talk to each other. This allows computers from
different vendors to communicate without problems. It's not a Microsoft-only
or an IBM-only or Sun-only or Macintosh-only network. The IAB is responsible for these
standards; it decides when a standard is necessary, and what the
standard should be. When a standard is required, it considers the
problem, adopts a standard, and announces it via the network. (You were
expecting stone tablets?) The IAB also keeps track of various numbers
(and other things) that must remain unique. For example, each computer
on the Internet has a unique 32-bit address; no other computer has the
same address. How does this address get assigned? The IAB worries
about these kinds of problems. It doesn't actually assign the
addresses, but it makes the rules about how to assign addresses.
As in a church, everyone has opinions about how things ought to run.
Internet users express their opinions through meetings of the Internet
Engineering Task Force (IETF). The IETF is another volunteer
organization; it meets regularly to discuss operational and near-term
technical problems of the Internet. When it considers a problem
important enough to merit concern, the IETF sets up a "working group"
for further investigation. (In practice, "important enough" usually
means that there are enough people to volunteer for the working group.)
Anyone can attend IETF meetings and be on working groups; the important
thing is that they work. Working groups have many different functions,
ranging from producing documentation, to deciding how networks should
cooperate when problems occur, to changing the meaning of the bits in
some kind of packet. A working group usually produces a report.
Depending on the kind of recommendation, it could just be documentation
and made available to anyone wanting it, it could be accepted
voluntarily as a good idea which people follow, or it could be sent to
the IAB to be declared a standard.
If you go to a church and accept its teachings and philosophy, you are
accepted by it, and receive the benefits. If you don't like it, you can
leave. The church is still there, and you get none of the benefits.
Such is the Internet. If a network accepts the teachings of the
Internet, is connected to it, and considers itself part of it, then it
is part of the Internet. It will find things it doesn't like and can
address those concerns through the IETF. Some concerns may be
considered valid and the Internet may change accordingly. Some of the
changes may run counter to the religion, and be rejected. If the
network does something that causes damage to the Internet, it could be
excommunicated until it mends its evil ways.
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The old rule for when things are confusing is "follow the money." Well,
this won't help you to understand the Internet. No one pays for "it";
there is no Internet, Inc. that collects fees from all Internet
networks or users. Instead, everyone pays for their part. The NSF pays
for NSFNET. NASA pays for the NASA Science Internet. Networks get
together and decide how to connect themselves together and fund these
interconnections. A college or corporation pays for their connection to
some regional network, which in turn pays a national provider for its
access. An individual pay for the connection to one's ISP (Internet
Service Provider) such as AOL, MSN, etc., which in turn pays a regional
network or national provider for its access.
Well, as we all know, death and tax are two most enduring
attributes of human culture. Correspondingly, there has been
increasing numbers and levels of attempt that the goverment wants to
tax the internet in forms of e-mail and e-commerce sales tax.
Justification, pros and cons are still debatable, however
it looks like that we're heading in that direction.
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What Does This Mean for Me?
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The concept that the Internet is not a network, but a collection of
networks, means little to the end user. You want to do something
useful: run a program, or access some unique data. You shouldn't have
to worry about how it's all stuck together. Consider the telephone
system--it's an internet, too. Bell Atlantic, Pacific Bell, AT&T, MCI, British
Telephony, Telefonos de Mexico, and so on, are all separate
corporations that run pieces of the telephone system. They worry about
how to make it all work together; all you have to do is dial.
If you ignore cost and commercials, you shouldn't care if you are
dealing with MCI, AT&T, or Sprint. Dial the number and it works. You
only care who carries your calls when a problem occurs. If something
goes out of service, only one of those companies can fix it. They talk
to each other about problems, but each phone carrier is responsible for
fixing problems on its own part of the system. The same is true on the
Internet. Each network has its own network operations center (NOC). The
operation centers talk to each other and know how to resolve problems.
Your site has a contract with one of the Internet's constituent
networks, and its job is to keep your site happy. So if something goes
wrong, they are the ones to gripe at. If it's not their problem,
they'll pass it along.
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What Does the Future Hold?
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It's not that I have a crystal ball
(if I did I'd spend my time on Wall Street),
rather, these are the things that the IAB and the IETF discuss at their
meetings. Most people don't care about the long discussions; they only
want to know how they'll be affected. So, here are projected
highlights of the networking future.
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When I was talking about how the Internet started, I mentioned the
International Standards Organization (ISO) and their set of protocol
standards. Well, they finally finished designing it. Now it is an
international standard, typically referred to as the ISO/OSI (Open
Systems Interconnect) protocol suite. Many of the Internet's component
networks allow use of OSI today. There isn't much demand, yet. The U.S.
government has taken a position that government computers should be
able to speak these protocols. Many have the software, but few are
using it now.
It's really unclear how much demand there will be for OSI,
notwithstanding the government backing. Many people feel that the
current approach isn't broke, so why fix it? They are just becoming
comfortable with what they have, why should they have to learn a new
set of commands and terminology just because it is the standard?
Currently there are no real advantages to moving to OSI. It is more
complex and less mature than IP, and hence doesn't work as efficiently.
OSI does offer hope of some additional features, but it also suffers
from some of the same problems which will plague IP as the network gets
much bigger and faster. It's clear that some sites will convert to the
OSI protocols over the next few years. The question is: how many?
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International Connections
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The Internet has been an international network for a long time, but it
only extended to the United States' allies and overseas military bases.
Now, with the less paranoid world environment, the Internet is
spreading everywhere. It's currently in over 80 countries, and the
number is rapidly increasing. Eastern European countries longing for
western scientific ties have wanted to participate for a long time, but
were excluded by government regulation. This ban has been relaxed.
Third world countries that formerly didn't have the means to
participate now view the Internet as a way to raise their education and
technology levels.
In Europe, the development of the Internet used to be hampered by
national policies mandating OSI protocols, regarding IP as a cultural
threat akin to EuroDisney. These policies prevented development of
large scale Internet infrastructures except for the Scandinavian
countries which embraced the Internet protocols long ago and are
already well-connected. In 1989, RIPE (Reseaux IP Europeens) began
coordinating the operation of the Internet in Europe and presently
about 25% of all hosts connected to the Internet are located in Europe.
At present, the Internet's international expansion is hampered by the
lack of a good supporting infrastructure, namely a decent telephone
system. In both Eastern Europe and the third world, a state-of-the- art
phone system is nonexistent. Even in major cities, connections are
limited to the speeds available to the average home anywhere in the
U.S., 9600 bits/second (or 9.6 Kbps).
Typically, even if one of these countries is
"on the Internet," only a few sites are accessible. Usually, this is
the major technical university for that country. However, as phone
systems improve, you can expect this to change too; more and more,
you'll see smaller sites (even individual home systems) connecting to
the Internet.
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Many big corporations have been on the Internet for years. For the most
part, their participation has been limited to their research and
engineering departments. The same corporations used some other network
(usually a private network) for their business communications. For example,
The IBM mainframes that
handled their commercial data processing did the "real" networking
using a protocol suite called System Network Architecture (SNA).
Businesses are now discovering that running multiple networks is
expensive. Some are beginning to look to the Internet for "one-stop"
network shopping. They were scared away in the past by policies which
excluded or restricted commercial use of the Internet. Many of these
policies have been changed. As a result, commercial use of
the Internet becomes progressively more common.
This should be especially good for small businesses. Motorola or
Standard Oil can afford to run nationwide networks connecting their
sites, but Ace Custom Software couldn't. If Ace has a Norfolk office
and a Washington office, all it needs is an Internet connection on each
end. For all practical purposes, they have a nationwide corporate
network, just like the big boys.
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Right behind commercialization comes privatization. For years, the
networking community has wanted the telephone companies and other
for-profit ventures to provide "off the shelf" IP connections. That
is, just like you can place an order for a telephone jack in your house
for your telephone, you could do this for an Internet connection. You
order, the telephone installer leaves, and you plug your computer into
the Internet. Except for Bolt, Beranek and Newman, the company that ran
the ARPAnet, there weren't any takers. The telephone companies have
historically said, "We'll sell you phone lines, and you can do whatever
you like with them." By default, the Federal government stayed in the
networking business.
Now that large corporations have become interested in the Internet, the
phone companies have started to change their attitude. Now they and
other profit-oriented network purveyors complain that the government
ought to get out of the network business. After all, who best can
provide network services but the "phone companies"? They've got the
ear of a lot of political people, to whom it appears to be a reasonable
thing. If you talk to phone company personnel, many of them still don't
really understand what the Internet is about. They ain't got religion,
but they are studying the Bible furiously. (Apologies to those
telephone company employees who saw the light years ago and have been
trying to drag their employers into church.)
Although most people in the networking community think that
privatization is a good idea, there are some obstacles in the way. Most
revolve around the funding for the connections that are already in
place. Many schools are connected because the government pays part of
the bill. If they had to pay their own way, some schools would probably
decide to spend their money elsewhere. Major research institutions
would certainly stay on the net; but some smaller colleges might not,
and the costs would probably be prohibitive for most secondary schools
(let alone grade schools). What if the school could afford either an
Internet connection or a science lab? It's unclear which one would get
funded.
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