2.2.4: IP Addresses

Another example of the need to reserve capacity for future use is afforded by IP (Internet Protocol) addresses, which is described in Section 2.8. These are (in version 4) of the form x.x.x.x where each x is a number between 0 and 255, inclusive. Thus each Internet address can be coded in a total of 32 bits. IP addresses are assigned by the Internet Assigned Numbers Authority, http://www.iana.org/, (IANA).

The explosion of interest in the Internet has created a large demand for IP addresses, and the organizations that participated in the development of the Internet, who had been assigned large blocks of numbers, began to feel as though they were hoarding a valuable resource. Among these organizations are AT&T, BBN, IBM, Xerox, HP, DEC, Apple, MIT, Ford, Stanford, BNR, Prudential, duPont, Merck, the U.S. Postal Service, and several U.S. DoD agencies (see Section 2.8). The U.S. electric power industry, in the form of EPRI (Electric Power Research Institute), requested a large number of Internet addresses, for every billable household or office suite, for eventual use by remote meter reading equipment. The Internet Engineering Task Force, http://www.ietf.org/, (IETF) came to realize that Internet addresses were needed on a much more pervasive and finer scale than had been originally envisioned—for example, there will be a need for addresses for appliances such as refrigerators, ovens, telephones, and furnaces when these are Internet-enabled, and there will be several needed within every automobile and truck, perhaps one for each microprocessor and sensor on the vehicle. The result has been the development of version 6, IPv6, in which each address is still of the form x.x.x.x, but each x is now a 32-bit number between 0 and 4,294,967,295 inclusive. Thus new Internet addresses will require 128 bits. Existing addresses will not have to change, but all the network equipment will have to change to accommodate the longer addresses. The new allocations include large blocks which are reserved for future expansion, and it is said (humorously) that there are blocks of addresses set aside for use by the other planets. The size of the address space is large enough to accommodate a unique hardware identifier for each personal computer, and some privacy advocates have pointed out that IPv6 may make anonymous Web surfing impossible.