Wireless Home Networking - Index of

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Part II: Making Plans
and other devices to which it has assigned IP addresses — issuing new
addresses as each device’s software requests an address.
NAT and broadband routers
A wireless router is a wireless AP that enables multiple computers to share
the same IP address on the Internet. This fact would seem to be a contradiction
because every computer on the Internet needs its own IP address.
The magic that makes an Internet gateway possible is Network Address
Translation (NAT). Most access points you buy now are wireless gateways.
Vendors sometimes call these wireless routers wireless broadband routers or
perhaps wireless cable/DSL routers. What you’re looking for is the word router
somewhere in the name or description of the device itself. Stand-alone access
points (without the router functionality) usually are called just an access
point, so sometimes it’s easier to look for something not called that!
In addition to providing NAT services, the wireless routers used in home
networks also provide the DHCP service. The router communicates with
each computer or other device on your home network via private IP
addresses — the IP addresses assigned by the DHCP server. (See the section
“DHCP servers,” earlier in this chapter.) However, the router uses a single IP
address — the one assigned by your ISP’s DHCP server — in packets of data
intended for the Internet.
In addition to providing a method for sharing an Internet connection, the NAT
service provided by a broadband router also adds a measure of security
because the computers on your network aren’t directly exposed to the
Internet. The only computer visible to the Internet is the broadband router.
This protection can also be a disadvantage for certain types of Internet
gaming and computer-to-computer file transfer applications. If you find that
you need to use one of these applications, look for a router with DMZ (for
demilitarized zone) and port forwarding features, which expose just enough of
your system to the Internet to play Internet games and transfer files. (Read
more about this topic in Chapter 11.)
A wireless Internet gateway is an AP that’s bundled with a cable, fiber-optic, or
DSL modem or router. By hooking this single device to a cable connection or
DSL line (or to the termination of your fiber-optic connection), you can share
an Internet connection with all the computers connected to the network,
wirelessly. By definition, all wireless Internet gateway devices also include
one (and typically, several) wired Ethernet port that enables you to add
wired devices to your network as well as wireless devices.