文档介绍：work Address Translation Works
by Jeff Tyson
If you are reading this article, you are most likely connected to
the and viewing it at the HowStuffWorks Web site.
There's a very good chance that you are work
Address Translation (NAT) right now.
The has grown larger than anyone ever imagined it
Special thanks to Cisco for its
could be. Although the exact size is unknown, the current
support in creating this article.
estimate is that there are about 100 million hosts and more than
350 million users actively on the . That is more than the entire population of the United
States! In fact, the rate of growth has been such that the is effectively doubling in size
each year.
So what does the size of the have to do with NAT? Everything! For puter to
communicate with puters and Web servers on the , it must have an IP address.
An IP address (IP stands for Protocol) is a unique 32-bit number that identifies the
location of puter on work. Basically, it works like your street address -- as a way to
find out exactly where you are and deliver information to you.
When IP addressing first came out, everyone thought that there were plenty of addresses to
cover any need. Theoretically, you could have 4,294,967,296 unique addresses (232). The actual
number of available addresses is smaller (somewhere between and billion) because of
the way tha