Web Running Out of Addresses

The Internet is about to run out of new addresses, a milestone that is spurring Web giants like Facebook Inc. and Google Inc. to develop new versions of their sites and prompting carriers like AT&T Inc. and others to upgrade networks.

This week, the organization that oversees Internet addresses is expected to dole out its last batch of existing Internet protocol addresses, a step akin to telephone companies running out of numbers to give customers. Internet protocol addresses are numerical labels that direct online traffic to the right location, similar to the way a letter makes its way through the postal system. Such routing is generally invisible to users -- when they type in www.facebook.com, for instance, they are actually connected to a computer located at the numerical address 66.220.149.32. It is those numbers that are in dwindling supply. While there is a new Internet addressing system ready to go that greatly expands the number of addresses, it isn't compatible with the existing system. So in June, Google, Facebook, Yahoo Inc. and others will switch over to the new addresses for one day in the first wide-scale test of the new network, dubbed IP version six, or IPv6. A permanent shift to a new Internet addressing system is still years off. But it is now inevitable.