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Add wireless to my lineup while retaining wired LAN

I would like to add wireless to my lineup (preferably via 802.11a for the higher throughput) while still retaining my wired LAN. I currently have a home network set up with a dedicated computer acting as a NAT router as well as providing DHCP, DNS, etc. Would this be as simple as just buying an 802.11a AP and connecting it to the switch that my NAT router is connected to? Also, what are my options for number of connections to an AP? Can I have 10 clients simultaneously connected? Can I have one client using 2 channels for double the throughput?
I assume that your computer that's acting as a NAT router and server has two interfaces - one connected (somehow) to the Internet, another connected via Ethernet to your home network. Your options:
  1. As you suggest, plug an 802.11 AP into the Ethernet switch shared by computers in your home network. WLAN stations will use DHCP to get addresses from and send Internet packets through your router/server PC. This works fine, but leaves your Ethernet open to wireless intrusion.

  2. Purchase an 802.11 router instead of an AP and use it to provide Internet access for both your WLAN and your Ethernet. Demote your router/server PC to just playing server on the Ethernet. This lets you apply security measures like MAC address lists uniformly and avoids turning your server PC into a bottleneck. However, it still doesn't protect your Ethernet from wireless intrusion.

  3. Option 2 with a twist: keep your router/server PC and Ethernet as they are, but plug the Internet port of the server PC into the 802.11 router, then connect the 802.11 router to the Internet. Your Ethernet is protected from the WLAN by the router/server PC. New wireless load is handled by the new router. If desired, the router/server PC can selectively expose public services to WLAN hosts. If WLAN hosts need access to other Ethernet hosts, use Microsoft VPN (PPTP) to connect WLAN hosts via the server PC.

You might be asking "Is security really necessary?" You have to decide how much you put at risk if a war driver (or your next door neighbor) connects to your new WLAN. To reduce risk, use MAC access control lists and turn on WEP encryption. For many home users, that's good enough. But realize that someone who really wants to break in can, unless you put a firewall between your WLAN and the rest of your network (which is what option 3 does.)

To answer your other questions: Most APs and routers have a simultaneous client connection limit, but that limit is usually more than the 10 clients you want. Check product specs. Also think about bandwidth ? that depends on your application, but 10 clients connected to one AP for Internet browsing and email is not unusual. Clients cannot use two channels to double their bandwidth; the AP/router and all clients operate on one shared channel.

This was last published in March 2003

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