Networking Explained, 2nd Edition

56 Networking Explained, Second Edition

1. Please begin by defining the Internet.

OK. We’ll try. Defining the Internet today is a bit more problematic, though, than it was

several years ago. Its definition varies from person to person. For example, during its early

years, the Internet was defined as a collection of computer networks based on a specific set

of network standards, namely, TCP/IP. This was the definition we gave in Chapter 1. Other

users, however, whose focus might be on the information they have acquired or the people

with whom they have communicated, might define the Internet as a global collection of

diverse resources, or as an electronic community of people. In fact, compared to the Inter-

net’s early days, some people have commented that the Internet has been transformed

from a community of networks to a network of communities. Still others, whose only

experience with the Internet is using the World Wide Web, might say the Internet and

World Wide Web are synonymous and hence the Internet is the World Wide Web. Conse-

quently, defining the Internet is a function of perspective. Regardless of the definition or

perspective, the Internet interconnects individual, autonomous computer networks and

enables them to function and appear as a single, global network.

2. How did the Internet get started?

The Internet’s roots can be traced back to 1957 when the United States formed the

Advanced Research Projects Agency (ARPA) within the Department of Defense (DoD).

The formation of ARPA was the United States’ response to the former Soviet Union’s

launch of Sputnik, the first artificial earth satellite. ARPA’s mission was to establish the

United States as the world’s leading country in defense- and military-applicable science

and technology. ARPA, which later became known as Defense ARPA (DARPA), estab-

lished in 1969 an early internetwork called ARPANET, the Advanced Research Projects

Agency Network. The builder of ARPANET was a company named Bolt, Baranek, and

Newman, which later became known as BBN Communications. Originally, the Internet

meant ARPANET, and access to ARPANET was restricted to the military, defense contrac-

tors, and university personnel involved in defense research. ARPANET technology was

based on packet-switching, and in 1969, with the connection of its first four nodes—Stan-

ford Research Institute (SRI), University of California at Santa Barbara (UCSB), Univer-

sity of California at Los Angeles (UCLA), and University of Utah—ARPANET heralded

the era of packet-switching networking.

3. I recall that the university I attended had a BITNET connection. Was this similar

to ARPANET?

Not quite. BITNET, which stood for Because It’s Time Network, was a low-speed and

inexpensive academic network consisting of interconnected IBM mainframes. BITNET

was one of several cooperative, decentralized computer networks that formed in the late

1970s and early 1980s on college and university campuses to serve the academic commu-

nity. Using a proprietary IBM-based network protocol, BITNET connectivity was via

9600 bps leased circuits and was based on the store-and-forward principle. Networking

services available via BITNET included file transfer, e-mail, and an IBM application

called remote job entry (RJE). In an RJE environment, small processors located at remote