Page 62 - Intelligent Communication Systems

46 INTELLIGENT COMMUNICATION SYSTEMS
for subscriber lines, asynchronous digital subscriber lines (ADSL) have been pro-
posed in the United Kingdom and other European countries. This method uses a
metallic cable to transmit information at 6-12 Mbps for downlink and at 640 Kbps
for uplink. To enable this service ADSL modems are installed at home and at the
telephone office. However, one drawback of ADSL is that the length of the sub-
scriber line is limited to 1 or 2 km. Through the introduction of information super-
highways, multimedia information can be transmitted in real time and new industries
will be created.
For the next-generation Internet, two initiatives were announced. In 1996, the
Internet 2 initiative was proposed by the university community of the United
States. According to this plan, the backbone network of Internet 2 was to provide
more than five times the transmission speed of the current backbone of the Inter-
net, meaning 1- to 10-Mbps network service to the end users. It focused on secu-
rity and quality of service (QOS).
The next-generation Internet initiative was announced by the Clinton admin-
istration. The initiative aimed to provide more than 100-1000 times the transmis-
sion speed of the current Internet. It focused on the real-time transmission of images
or motion pictures. It was planning to be applied to telemedicine, telecollaboration,
and/or tele-education. In 2000, the Japanese government announced a high-speed
information infrastructure initiative by which high-speed subscriber lines would be
constructed over the next five years to transmit motion pictures to subscribers in
real time.
As information technology progressed, demands for enhancement of the net-
work grew. For example, a high-speed network was needed to transmit a huge
amount of multimedia information among institutes, including 3D images and
motion pictures. To achieve this, projects to enhance the network were conducted
in the 1990s. Two projects are described here: the gigabit network test bed project
and the super-high-speed backbone network project.

6.1 THE GIGABIT NETWORK TEST BED PROJECT

The gigabit network test bed project was conducted by the National Research and
Education Network (NREN) program until 1995. About 40 institutions, including
universities, common carriers, computer manufacturers, and research institutes,
participated in this project and had experiments for the development of applica-
tion programs running on the gigabit network. There were five test beds in the proj-
ect: Aurora, Blanca, Casa, Nector, and Vistanet. The project was inaugurated by
the National Science Foundation (NSF) and the Defense Advanced Research Project
Agency (DARPA).
The Corporation for National Research Initiative (NRI) was an organiza-
tion for coordination among members of the consortium and the federal govern-
ment. The government spent about $20 million for research over five years.