Jeff Duntemanns Drive-By Wi-Fi Guide

Choosing an Access Point or Gateway

Having read this chapter so far, you should know enough to be able to make an intelligent decision as to what access point or gateway products to buy for your home or small office network. To conclude this chapter, let me offer some points to keep in mind as you make your buying decisions.

1. If at all possible, purchase all your Wi-Fi gear from the same manufacturer. There are gaps and fuzzy areas in the Wi-Fi standard, and some of them (like WEP security) are crucial. Your chances of having everything talk to everything else on your network are greatest if both access points and client adapters are from the same manufacturer. If you make exceptions, make them for PCMCIA cards for your laptop. (See Chapter 7 for more on the various types of client adapters.) If you intend to use an 'enhanced' Wi-Fi technology like 802.11b+, you must use gear from the same manufacturer, or you will lose the benefits of the enhancements.

2. If your network only requires one access point, buy a wireless residential gateway. This applies to the '85% solution' I described in Chapter 4. Small houses, townhouses, apartments, and condos are unlikely to require more than a single 'center point' for your network. You can make things much easier to set up and configure by using a residential gateway rather than a separate router and access point. On the other hand, consider the next issue…

3. If you may need multiple access points, use a separate router appliance and add access points to the network as required. Large homes, oddly-shaped homes (including very tall and very slender row houses and brownstones), and midsized offices may require you to place access points somewhere other than where your broadband Internet connection enters the premises. My experience in adding additional access points to networks based on residential gateways has not been good. Once you step away from the 85% solution, go with separate access points and not gateways.

4. Choose access points or gateways with dual antennas, ideally removable antennas. Some access points and gateways have their antennas built right into the plastic case, which in my view is a bad idea. You can sometimes finesse a weak spot or a dead spot by re-orienting an access point's external antennas- remember TV rabbit ears?-and products with external antennas are not automatically more expensive. Removable antennas allow you to mount external omni gain antennas if you need to. See Chapter 8 for more on this issue.

5. If you're not pinched for cash, dual-mode products are worth a shot. My early experiments with dual-mode Wi-Fi gear (single products that support both 802.11b and 802.11a) have been good, but it's very early in the product cycle, and dual-mode still costs a lot more than 802.11b. (At this writing, about two and a half times more!) 802.11a, because it has a shorter range than 802.11b, actually makes more sense in very small spaces like apartments and condos. Dual mode allows you to hedge your bets, and get the best of both technologies. Still, dual-mode hasn't existed long enough for us to know what all the non-obvious problems may be.

What About Used Gear?

People regularly ask me if I think buying used gear is a good idea. Sure-as long as you can be sure you're not being taken. I have been astonished to see used Wi-Fi gear sold on eBay for more than the street price for the same gear new through reliable channels, which is a weirdness I doubt I will ever understand unless this has to do with WiFi's demand in countries that already have a hard time importing gear. Here are ome pointers to consider when shopping for used gear:

• Know the current new price. Do some Web research. Prices are volatile and can drop radically without warning. Some people can't bear to sell used gear for much less than they paid for it, especially if they haven't had it long, so don't assume that a used price is lower than the new price!

• Pay attention to details like version numbers, firmware release levels, and precise model numbers. D-Link has a DWL-900AP and a DWL-900AP+, and they are not the same device! Linksys has a USB client adapter (the WUSB11) with three radically different configurations under the same name. Version 2.5 has a removable antenna, but version 2.6 does not. The cases are not the same size and shape.

• If you're buying gear from people you know, ask to try it out.

• Make sure you get all the parts: software CD, printed manual, power supply, connecting cables, detachable antennas. It helps to check a manufacturer's Web site to learn what's in the new package before you buy something used.

My Recommendations

I have used both Linksys and D-Link wireless gear with great success, and recommend both for fairly simple networks. Both companies offer very complete product lines, and their prices are quite competitive. Once you get into enterprise territory, Cisco Aironet becomes pretty compelling, especially if you intend to integrate wireless with a centralized authentication server.

At press time both Linksys and D-Link have released purportedly 802.11g gear, but the IEEE 802.11g standard has not yet been finalized and I'm suspicious at how 'standard' such gear may be. (At least Linksys doesn't precisely call it 802.11g, but draft 802.11g.) Keep in mind that pioneers get arrows, and hang on until the 802.11g standard is complete. For more on 802.11g, see the 802.11 Standards Encyclopedia at the end of this book.

I recommend D-Link's AirPlus DWL-900AP+ access point for bridging (to another identical unit-see Chapter 16) but I am less enthusiastic about it for use in infrastructure mode, as it only has a single antenna.

The Linksys BEFW11S4 wireless residential gateway is my personal favorite for very simple 85% solution networks. It's gotten quite cheap and my unit has held up well in continuous use for 18 months.

Often it makes sense to decide what sorts of client adapters you need for your network before you buy your access point or gateway, to be sure that you can get everything from the same manufacturer. Not all vendors offer a USB client adapter, for example, and if you want a single-vendor network, you may need to look at what sorts of client devices are available before choosing a vendor. On general principles I recommend reading Chapter 7 and thinking hard about what sorts of clients you need before committing to either a vendor or an access point or gateway model.