Hardware Reference
In-Depth Information
waves, enabling you to create a wireless backbone that can cover a wide area (such as
a warehouse) without the need to run network cabling. You can also purchase a wire-
less Ethernet range extender that can receive and boost weak Wi-Fi signals. Some access
points are designed to be used as either access points or range extenders. Some range ex-
tenders are designed only to work with the same brand of access point or router.
Access points are not necessary for direct peer-to-peer networking (also called
ad hoc
mode
), but they are required for a shared Internet connection or a connection with another
network. When access points are used, the network is operating in
infrastructure mode
.
Note
Wireless clients running in ad hoc mode cannot connect to the Internet unless one of the sta-
tions on the network is connected to a bridge or uses another network adapter as a bridge.
NICsequippedforwirelessEthernetcommunicationshaveafixedordetachableradioan-
tenna. Wireless NICs come in four forms:
• CardBus (32-bit PC Card) or ExpressCard (PCIe) cards for use in laptop computers
that do not include “integrated” wireless support
•MiniPCIorPCIeMinicardsthatprovidewirelessandwiredEthernetanddial-upmo-
dem support for laptop computers
• PCI cards for use in desktop computers with PCI slots
• USB adapters for use in both desktop and laptop computers
Most laptop computers with Wi-Fi hardware onboard use the Mini PCI or PCIe Mini in-
terface for the wireless adapter and place the antenna inside the display housing.
Note
Mini PCI or PCIe Mini cards are installed inside laptop computers. (They can be removed or
replaced by opening the system.) Because Mini PCI and PCIe Mini cards are installed inside
laptops, they are not usually sold as retail components. However, some vendors sell them as
OEM components, or you can buy them from the laptop vendor's parts department.
Because you can mix and match Wi-Fi-certified products that use the same frequency
band, you can incorporate any mix of desktop and laptop computers into your wireless
network.
Figure 17.18
illustrates typical wireless network hardware.
Figure 17.18
A typical family of Wi-Fi 2.4GHz band (802.11g) wireless products, including a wireless
router, USB, CardBus, and PCI wireless network adapters.
