Large Numbers" at the following URL: http://en.wikipedia.org/wiki/Names_of_large_numbers I have eight IP addresses, though I only rent them from my provider. My mother uses one. The average person might consume one if he has a cable or DSL Internet connec- tion. Companies that connect directly to the Internet might have 256, though they probably don't use them all. There are many developing countries coming online that are consuming large quantities of IP addresses. Heck, there are almost seven billion people on Earth today. There aren't enough IP addresses for everyone, even if I give up my eight, and I'm not about to. To resolve this situation, The Internet Engineering Task Force (IETF) came up with the next version of IP, called IPv6. Why not IPv5, you ask? The version is identified in the version field of the IP packet. Version 4 is naturally used for IPv4, but version 5 was already allocated for something called the Internet Stream Protocol (ST, ST+, and ST2), SO the IETF had to use the next best thing. If you're interested in learning more about the Internet Stream Protocol, check out RFC 1819. IPv6 was originally published in 1998 within RFC 2460 and, as of this writing, has been updated with RFCs 5095, 5722, and 5871. There are many other RFCs that cover IPv6 or how other protocols have been modified to work with IPv6. Per RFC 2460, the changes from IPv4 fall primarily into the following categories: Chapter 37: IPv6 Expanded addressing capabilities IPv6 increases the IP address size from 32 bits to 128 bits to support more levels of addressing hierarchy, a much greater number of addressable nodes, and simpler autoconfiguration of addresses. The scalability of multicast routing has been im- proved by the addition of a "scope" field to multicast addresses. And a new type of address, called an anycast address, has been defined to send a packet to any one of a group of nodes. Header format simplification Some IPv4 header fields have been dropped or made optional to reduce the common-case processing cost of pa