Abstract
The high speed and cheap Internet connectivity have spreaded quickly by ADSL. But the network connection between construction sites and branches still use ISDN line, and cannot attain improvement in speed. First, since the characteristic of network connection of a work place is analyzed, and the requirements needed for the Internet use for general consumers are summarized. And the method of Internet VPN System is described to be sufficiently secured and stabile to a company. As a result of connecting about 200 sites, this made it possible to increase transmission speed to 5 or more times of the conventional ISDN, and to cut cost to 28%.
