TCP/IP Tutorial and Technical Overview - IBM Redbooks

activities,” unless covered by the General Principle or as a specifically
acceptable use. However, in spite of this apparently restrictive stance, the
NSFNET was increasingly used for a broad range of activities, including many of
a commercial nature, before reverting to its original objectives in 1995.
The provision of an AUP is now commonplace among Internet service providers,
although the AUP has generally evolved to be more suitable for commercial use.
Some networks still provide services free of any AUP.
Let us now focus on the Internet service providers who have been most active in
introducing commercial uses to the Internet. Two worth mentioning are PSINet
and UUNET, which began in the late 1980s to offer Internet access to both
businesses and individuals. The California-based CERFnet provided services
free of any AUP. An organization to interconnect PSINet, UUNET, and CERFnet
was formed soon after, called the Commercial Internet Exchange (CIX), based
on the understanding that the traffic of any member of one network may flow
without restriction over the networks of the other members. As of July 1997, CIX
had grown to more than 146 members from all over the world, connecting
member internets. At about the same time that CIX was formed, a non-profit
company, Advance Network and Services (ANS), was formed by IBM, MCI, and
Merit, Inc. to operate T1 (subsequently T3) backbone connections for NSFNET.
This group was active in increasing the commercial presence on the Internet.
ANS formed a commercially oriented subsidiary called ANS CO+RE to provide
linkage between commercial customers and the research and education
domains. ANS CO+RE provides access to NSFNET as well as being linked to
CIX. In 1995 ANS was acquired by America Online.
In 1995, as the NSFNET was reverting to its previous academic role, the
architecture of the Internet changed from having a single dominant backbone in
the U.S. to having a number of commercially operated backbones. In order for
the different backbones to be able to exchange data, the NSF set up four
Network Access Points (NAPs) to serve as data interchange points between the
backbone service providers.
Another type of interchange is the Metropolitan Area Ethernet (MAE). Several
MAEs have been set up by Metropolitan Fiber Systems (MFS), who also have
their own backbone network. NAPs and MAEs are also referred to as public
exchange points (IXPs). Internet service providers (ISPs) typically will have
connections to a number of IXPs for performance and backup. For a current
listing of IXPs, consult the Exchange Point at:
http://www.ep.net
Similar to CIX in the United States, European Internet providers formed the RIPE
(Réseaux IP Européens) organization to ensure technical and administrative
Chapter 1. Architecture, history, standards, and trends 17