TCP/IP Tutorial and Technical Overview - IBM Redbooks

Integrated Digital Network Exchange (IDNX) supplied by IBM was installed at
each of the 13 locations, to provide:
– Dynamic alternate routing
– Dynamic bandwidth allocation
► Third backbone: In 1989, the NSFNET backbone circuits topology was
reconfigured after traffic measurements and the speed of the leased lines
increased to T1 (1.544 Mbps) using primarily fiber optics.
Due to the constantly increasing need for improved packet switching and
transmission capacities, three NSSs were added to the backbone and the link
speed was upgraded. The migration of the NSFNET backbone from T1 to T3
(45 Mbps) was completed in late 1992. The subsequent migration to gigabit
levels has already started and is continuing today.
In April 1995, the U.S. government discontinued its funding of NSFNET. This
was, in part, a reaction to growing commercial use of the network. About the
same time, NSFNET gradually migrated the main backbone traffic in the U.S. to
commercial network service providers, and NSFNET reverted to being a network
for the research community. The main backbone network is now run in
cooperation with MCI and is known as the vBNS (very high speed Backbone
Network Service).
NSFNET has played a key role in the development of the Internet. However,
many other networks have also played their part and also make up a part of the
Internet today.
1.2.3 Commercial use of the Internet
In recent years the Internet has grown in size and range at a greater rate than
anyone could have predicted. A number of key factors have influenced this
growth. Some of the most significant milestones have been the free distribution
of Gopher in 1991, the first posting, also in 1991, of the specification for hypertext
and, in 1993, the release of Mosaic, the first graphics-based browser. Today the
vast majority of the hosts now connected to the Internet are of a commercial
nature. This is an area of potential and actual conflict with the initial aims of the
Internet, which were to foster open communications between academic and
research institutions. However, the continued growth in commercial use of the
Internet is inevitable, so it will be helpful to explain how this evolution is taking
place.
One important initiative to consider is that of the Acceptable Use Policy (AUP).
The first of these policies was introduced in 1992 and applies to the use of
NSFNET. At the heart of this AUP is a commitment “to support open research
and education.” Under “Unacceptable Uses” is a prohibition of “use for for-profit
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