Dartblog

Jeff Jarvis has a wireless router that doesn’t cover his entire home. He’s tried to fix the problem with “range extenders” (those are actually radio repeaters of the type police departments mount on electrical poles) and with “boost antennae” (those amplify the radio signal a few dBi through wire patterns and work exactly like aluminum foil, only more expensive and less cool-looking) to no significant success.

I recently had to install a wireless network at my family’s new house, a three-story townhouse near the NJ-PA border with many walls and signal traps. Worse, the data hub—where telephone, cable, internet, and other services enter the home—is in the cement basement. In order to have permeating wireless coverage, the only satisfactory solution is to install multiple access points.

First, some schoolin’. The path for a home network that exists to share a broadband internet connection is rather simple. In the following order, you need: a modem, a gateway, a router, a switch, and, if wireless is desired, an access point. Your modem (a modulator/demodulator) is the el-cheapo modem provided, in Jeff’s case, by Comcast if he uses cable service or Verizon if he uses DSL (digital subscriber line). A modem simply takes the raw feed provided by the coax or RJ11 entering your house from the street and converts it to sensible Ethernet data. It outputs to a RJ45 plug, which is the just-wider-than-a-phone-plug that you use to connect your laptop at work or school.

The RJ45 output of the modem goes into the RJ45 input of a gateway, which is a network device that allows one network (the one you are building in your home) to sense an entirely different network (the Internet as provided by your ISP). That gateway then connects to a router, which is a sort of network hub on steroids. Instead of simply interconnecting a bunch of wires like a hub, a router interconnects a bunch of wires but doesn’t let those juicy bits flow any which way: it intelligently tells which packets to go where, enabling multiple computers to send requests for data and then receive that data without collisions. The router merely makes the internet signal as provided by the gateway a “shareable” one. To actually share it, you need a switch. A switch falls between a hub and a router in terms of intelligence. It interconnects wires, but does so in full-duplex and at constant full-speed (which a hub cannot) but it does not know how to talk to the internet in the way a router can.

But once your internet connection has gone through a router, you can insert it into a switch just like any other computer.

Now that you are unconscious and drooling on the keyboard, I’ll tell you how to do all this. It’s easy because of one delightful little fact: that $60.00 Linksys wireless router that everyone and his brother owns is a gateway, router, switch, and access point all in one.

Here is how my network is set up. It consists of 5 desktop computers directly wired into the network and three wireless access points scattered through the house, allowing any number of laptop users to surf the internet from the comfort of the couch. First, Comcast’s cable modem enters the house (it is always a good idea, when reconfiguring a network, to unplug your modem for 60 seconds and let it forget everything it thought it knew about itself) and its single RJ45 port (you cannot use USB-only modems) connects to the RJ45 “Internet” or “WAN” port of my broadband router. Now the router has the internet, has given it a gateway to my network, is routing the packets, and can act as a wired switch for up to four wired computers and a wireless access point for 10 or so wireless users.

But I have more than four computers, so I needed an external switch. I bought a simple 8-port switch for $50 and plugged it in. Remember: a switch intelligently connects computers to form a network, and a gateway/router interprets the internet such that it looks like a sensible computer on your network. So with the modem connected to the router, all I need to do is use one of the router’s four switch ports and connect it to my big 8-port switch. Now one of the computers on my network is “the Internet.” I connected the other five computers to the switch too. That leaves two ports left.

I’ve already got one wireless access point, because the router itself has the internet signal and is broadcasting it into the ether. What I need are two more, since that one basement signal doesn’t fill the house. Since Linksys’ most popular product is the router and not many people need multiple access points, the individual APs are more expensive and difficult to find. But here’s the secret: any old Linksys router that you have around (or can buy for $60 from RadioShack) can be turned into a dumb access point. I have two of these extra Linksys routers.

I placed them in two rooms on the second floor, plugged them in, and connected them to my network (not through the “Internet” or “WAN” port but through one of those four ports on the back, since we already have a gatewayed and routed internet signal) to that 8-port switch we talked about. (Mine, recall, is in the basement and the wiring was all done before the sheetrock went up. But the switch and your ancillary access points can be as far or as close as you want.

At this point those additional routers think they are gateway/routers, instead of just access points. We don’t want that. So get a laptop and a short network cable and plug into another of the four ports on the back of the routers you want to turn into access points. Surf your browser to 192.168.1.1, which is the default IP address of a Linksys router. When prompted to login, the default credential is a blank username and ‘admin’ for the password. If you don’t know the password, not even the Almighty himself can help you. (A giant magnet might, though.)

You need to make a few changes to get the router to stop trying to be such a wisenheimer with your network. First, find the option to disable the DHCP server. Do it. (This is why Jeff Jarvis was getting ‘junk’ IP addresses. Every assigned IP address must come from your original router.) Then change the local IP address (the IP you typed in to administer this router) to 192.168.1.2, or anything that is the same as the original router up to the very last number, but less than 100. Then you won’t get sent back to the admin page, because the router’s IP changed. Retype the new one into your browser. Now find the Advanced Routing page and change your router’s operating mode from gateway to router. Keep RIP disabled.

These steps can be repeated (using a different IP address each time) with any number of extra routers. When it is all done, you will have a situation where wireless fills your home and where any network jack—even those three remaining jacks on the back of the extra routers—can be used to connect to the internet. After you’ve done all of this, though, find a tutorial on the Internet and make your wireless network secure.

If you have any problems, hesitate to e-mail me. And to readers who work in IT and just read this whole thing: please stop laughing.