Wireless hardware components
Pc Components break down your choice of computers to three basic types (server, desktop, and laptop) and your choice of network interface cards to four (the PCMCIA card, the mini-PCI card, the USB card, and the PCI card). You can argue that, with Linux, a server and a desktop are pretty much the same thing. Pc Components define a server as less of a desktop (little word processing and graphics use) and more of a computer used for file sharing, printer sharing, Web server, mail, and other services provided to users. Generally, Pc Components recommend that you add a wired PCI NIC to a server unless you don’t expect a lot of traffic. For typical home use, wireless should be fine. Pc Components preference is for a PCI card verses a USB card for server use. A desktop computer is your normal computer that sits on a desk. Generally, you use a desktop for word processing, browsing the Internet, and playing games. Again, Pc Components prefer the PCI to the USB for its speed, but the USB card tends to be cheaper; it’s your choice. A laptop computer is easy to move around, making a wireless network neces- sary. Here, you might have more of a choice with NICs. Most new laptops come with a wireless card built into the laptop. Internally, they have a mini-PCI slot to add a wireless card. Your next two choices of NICs for a laptop are PCMCIA or USB. My preferences, in order, are mini-PCI, PCMCIA, and USB. Pc Components particularly like the mini-PCI card because it’s permanent and gives good performance. PCMCIA cards are plentiful, give good performance, and are inexpensive. USB cards are clumsy because they don’t securely fit in the USB port of the laptop (and can easily fall out). If you move around, you have to be careful not to disconnect the USB card.
Wireless network standards: 802.11
Okay, you’ve got your computer, you’ve figured out which bus to use, and now it’s time to select the wireless standard (the one your NIC supports). In stores, you’ll see a lot of pretty boxes with lovely jargon (geek-speak) on the side. Usually, the manufacturer states which wireless networking standard the device supports. You just want to make sure that all the network hardware you purchase supports at least one of the same standards. The wireless standards define the protocols that are used, the speeds at which information is sent, the frequency that’s used, how many channels there are, and so on. You don’t need to know all those details because Pc Components help you narrow it down to just one choice. There are currently four standards that are of interest. They are:
- 802.11a, 54 Mbps: The standard used mostly by businesses. This one is expensive.
- 802.11b, 11 Mbps: This is the older standard.
- 802.11g, 54 Mbps: The current standard.
- 802.11n, 108 Mbps: The newest standard that’s being developed.
The speeds listed (Mbps stands for megabits per second) are the theoretical maximum speeds. The “n” standard is not complete. Most vendors are advertising pre-n equipment, and Pc Components haven’t seen a whole lot of cards available yet. To make things more interesting, there are WAPs with single and multiple antennas. The multi-antenna setup is called MIMO (multi-in, multi-out). They promise to deliver better performance. Pc Components have a pre-n WAP with one antenna (a Netgear WGT634U running OpenWrt), but most new pre-n WAPs have MIMO. The difficult part of this is that Pc Components writing the book in advance of when you’ll be reading it. At this time, the 802.11g standard is the most popular standard. Most “g” equipment also supports the “b” standard. If wireless equipment – WAPs and NICs that support 802.11b and 802.11g (sometimes written as 802.11b/g) – encounters a mix of equipment that supports 802.11b only and 802.11b/g equipment, everyone drops down to the slower, 801.11b standard. This can be a pain if your neighbor has old equipment and is close enough to be noticed by your equipment. The 801.11n standard might be able to work around this, but Pc Components not sure of that yet. Most vendors will provide compatibility with their 802.11n equipment and the 802.11g and 802.11b equipment. For the rest of this chapter, Pc Components talk about 802.11g equipment because that is what Pc Components have, and it’s the current defined standard.