Understanding Ip Addressing: Everything You Ever Wanted to Know

Understanding IP Addressing: Everything You Ever Wanted To Know

The Internet continues to grow at a phenomenal rate. This is reflected in the tremendous popularity of the World Wide Web (WWW), the opportu- nities that businesses see in reaching customers from virtual storefronts, and the emergence of new ways of doing business. It is clear that expanding business and public awareness will continue to increase demand for access to resources on the Internet.

Internet Scaling Problems

Over the past few years, the Internet has experienced two major scaling issues as it has struggled to provide continuous and uninterrupted growth:

* The eventual exhaustion of IP version 4 (IPv4) address space

* The need to route traffic between the ever increasing number of net- works that comprise the Internet

The first problem is concerned with the eventual depletion of the IP address space. IPv4 defines a 32-bit address which means that there are only 232 (4,294,967,296) IPv4 addresses available. As the Internet con- tinues to grow, this finite number of IP addresses will eventually be exhausted.

The address shortage problem is aggravated by the fact that portions of the IP address space have not been efficiently allocated. Also, the tradi- tional model of classful addressing does not allow the address space to be used to its maximum potential. The Address Lifetime Expectancy (ALE) Working Group of the Internet Engineering Task Force (IETF) has expressed concerns that if the current address allocation policies are not modified, the Internet will experience a near to medium term exhaus- tion of its unallocated address pool. If the Internet's address supply problem is not solved, new users may be unable to connect to the global Internet. More than half of all possible IPv4 addresses have been assigned to ISPs, corporations, and government agencies, but only an estimated 69 million addresses are actually in use.