Experts at FutureNet, an annual conference held to address communications services, say the Internet architecture will face severe challenges over the next few years that could significantly strain the Web's effectiveness. One of the most prominent issues facing the Internet is the impending shortage of IP addresses, which some forecasters say could occur within the next few years. IPv4 offers about 4.7 billion possible IP addresses, but it is running out of capacity. Juniper's Ron Bonica says there are three likely solutions to this problem. The first is to sick with IPv4, which would create some immediate problems with the impending shortage of IP addresses but would also lead to the creation of an IP address trading system through which companies and individuals that own an excessive number of addresses could sell them at market value. Another possibility would be a rapid deployment of IPv6, the next generation Internet Protocol that is capable of supporting several billion more addresses than IPv4. Bonica says many companies and organizations are reluctant to make the switch because it will require significant investments on the part of end users and ISPs, and transition mechanisms to help make the switch have not been deployed yet. Bonica says the third option is a compromise between these two solutions that involves a gradual shift from IPv4 to IPv6. Another issue addressed FutureNet addressed was the strain more IP addresses will place on routing tables, which are not scalable and cannot adapt to exponential increases in IP addresses. "The basic, fundamental problems of scaling a network haven't been addressed in any innovative manner," says American Registry of Internet Numbers Chairman John Curran.