The Universe of Networks

The world today is served by a vast number of different electronic communications networks
accessible to the public. Some of these exist in a hierarchical relationship to one another while
others are autonomous or semiautonomous. What is important to recognize is that the latter—
namely, the more or less isolated networks—are coming to be viewed as increasingly anachronistic.
Where in the past networks such as cable television systems and two-way dispatch radio
networks were truly autonomous, now both are likely to be connected to the Internet and to
the public switched telephone system, and thus ultimately to one another. Even paging networks
tend to have Internet and telephone interconnectivity today.
Currently, two all-embracing networks exist, the PSTN and the Internet, which is the universal
network of data networks. The Internet, back in the days when it is was known as
ARPANET and was designed primarily to serve the needs of the military and other government
agencies, was conceived as an overlay on the PSTN, which would utilize many of the Bell Operating
System network elements already in place. For this reason the two cannot readily be
distinguished or disentangled from one another.
The traditional PSTN is in the process of gradually morphing into a sort of “super Internet”
or next-generation Internet, a process that has crucial implications for everyone in the broadband
access today—or in any other aspect of telecommunications, for that matter. When that
process is completed, the procedures of connecting one physical network with another, such
as a wireless broadband network with a fiber ring, will become simple and straightforward.
Moreover, the role of every business entity owning physical infrastructure is apt to change as a
result, in some ways that are still unpredictable but in others that are apparent even now (I will
discuss these ways in later sections). For now, functional and structural distinctions continue
to exist among networks, and it is to these that I will now turn your attention.