There are some things that are just meant to go together. If you like Reese's Peanut Butter Cups you might think of chocolate and peanut butter. In the world of Pocket PCs, two things that go together very well are wireless cards and local area networks.

In Philadelphia in late May, the Pocket PC was combined with wireless networking again. As it did for the Pocket PC Summit in October of last year, Symbol again loaned a number of wireless access points and Chris De Herrera donated a lot of time to pull off a 802.11b (Wi-Fi) wireless LAN for all of the conference attendees. In addition, Symbol loaned their CompactFlash networking cards and a limited number of their industrial Pocket PCs so attendees could get first-hand experience with a wireless LAN.

Symbol's Wireless Networker LAN card is small enough that it barely affects the outline of an iPAQ.

WHAT IS A WIRELESS LAN?

A wireless LAN is, obviously, wireless. It has two other basic aspects. A wireless LAN operates only within a relatively small set of boundaries: generally within a building, or within a campus of buildings. Additionally, a wireless LAN is relatively high speed. That is to say, it is high speed when compared to the available cellular solutions. While cellular solutions allow access from a much larger area, they operate at slower speeds. Both wireless LANs and cellular wireless are slower than state-of-the-art wired LANs.

WIRELESS OPTIONS

Although there are several kinds of wireless LANs in use today, people usually use the term to refer to the IEEE 802.11b standard for wireless networking. This standard has been branded with the name Wi-Fi. It uses a 2.4 GHz spectrum like some high-end cordless phones, video repeaters (which retransmit video signals), and many other applications. The Wi-Fi standard is capable of transmitting data at a rate of up to 11Mbps in strong signal conditions.

Wi-Fi networks are by far the most popular wireless LAN in use today because of their relatively low cost and their reasonable data rate. However, two newer standards, IEEE 802.11a and IEEE 802.11g, show some promise. 802.11a allows for data transmission rates of up to 54 Mbps and uses the 5GHz spectrum, which is much less crowded than the 2.4 GHz spectrum that Wi-Fi runs in. 802.11g uses the same 2.4 GHz spectrum as 802.11b but doubles the data rate to 22 Mbps.

One of the things that confuses most people is the lettering convention that is used by the IEEE in the naming of the standards. For instance, 802.11b is older than 802.11a. It's better to try not to think too much about the official IEEE numbering and lettering.

WIRELESS 101: A SINGLE ACCESS POINT

Putting together a wireless LAN that will live within a radius of no more than 100 meters (300 feet) is relatively easy. You place a wireless access point (WAP) in the center of the coverage area and connect it to your existing Ethernet network. Then all you need is a wireless network card for each computer you want to connect via the wireless network.

From a configuration perspective, you need to know a few important parameters. Perhaps the most important is the Service Set Identifier (SSID), sometimes called an Enhanced Service Set Identifier (ESSID). This setting is used to differentiate wireless networks that may be running in the same space. The SSID/ESSIDs will need to match between the access point and network cards on the network.

In addition to the SSID/ ESSID, there are several security parameters that should be set, but we'll cover those in the section dedicated to security.

WIRELESS 201: MULTIPLE ACCESS POINTS

Setting up a wireless LAN with one access point seems simple enough, but what happens when you need more coverage than you can get from a single access point? It's actually not that much more complicated. The biggest thing is to connect the second access point to the same network as the first access point.