Networking / Beginners

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Cascading APs from a central router

Cascading APs from a central router works well if you have a really big home or office or a lot of users. In this scenario, you need, for reasons of coverage or capacity, to have multiple access points on your network - and you want them all to be on the same subnet.

Tip Why would you want these wireless APs on the same subnet? Simply because you want to be able to do all of those fun (and common) networking things between and among the devices connected to the networks. For example, say you have two APs. Let's call them Opie and Cherry (not that either of your authors would name his AP ESSIDs after his dogs). You want a computer on Opie to be able to access network resources (like a printer server) connected to Cherry - the networks would have to be on the same subnet to do this.

To set up this kind of a network, you'd need to have a single router providing connectivity to the Internet connection, handling NAT and handing out IP addresses to client devices (via DHCP or manual configuration). How you make such a connection physically depends upon what kind of gear you've got on your network.

If you've got a wireless broadband router (that is, one of your APs is also your router), you would simply connect the second (and third, and so on) APs to one of the wired switch ports on your broadband router. If you are using a separate wired router with a built-in Ethernet switch, you would connect both APs to ports on that switch.

If you've got a really big network in your home that would exhaust the four or eight ports on most home routers, you'll probably have a router and a separate multiport (16 or more) Ethernet switch. (Danny's network is like this, with his 12 computers and countless other devices.) In this case, you can connect the APs to ports on this big switch.

Regardless of the physical layout (which varies depending on your unique situation), the logical layout is the same. The steps below explain (in general terms) how to set up a network of multiple APs, all controlled from a centralized router.

1. Set up your main router to provide IP addresses to devices on your network.
   If you're going to use DHCP for this (and you may want to), turn DHCP on. To do so, look for a setting called something like LAN DHCP Server or Distribute IP Addresses Automatically and select it.
   Remember Your main router may be one of your wireless APs if you don't have a separate router. (Most people don't have a separate router!) If you don't, make sure DHCP is enabled in whichever wireless AP is connected directly to your Internet connection.
2. Go into the configuration page or program for your other APs (or all of your APs, if you have a separate router) and turn off the setting that enables DHCP.
   When turning this off, you may see text indicating that you are configuring the AP to work in "bridge" mode, or something along those lines.
3. Restart your APs (use the configuration software or simply power them down and back up manually).

In this scenario, all of your networked devices communicate through the AP with which they are associated (you control that with your device's drivers and operating system) and connect back to your router. All devices are on the same subnet.

Remember One thing to keep in mind is that you may want to change the channels on each of the APs to separate nonblocking channels before you change them into bridge mode. If one AP is too close to another, they can interfere with each other and slow down the performance of your wireless network.