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How to link wired LANs using wireless network bridges and APs

Our wireless networking expert aids an administrator deploy a WLAN in this response to the question "How can I link my wired LANs using ZyXEL's B-3000 access point (AP) and B-420 wireless bridges?"

I have a customer who owns a three-building hotel where I am deploying a WLAN. There are approximately 100 feet between Building A (which houses the wired LAN) and Building C (to the North) and Building B (to the East). I am using a ZyXEL B-3000 access point (AP) and three B-420 wireless bridges.

I am having trouble bridging between ZyXEL B-420's to connect all three buildings. All bridges have the same settings, including the same gateway (the router on the wired LAN). In Building A, I have deployed both a B-420 and a B-3000 AP, and they are plugged into the same Ethernet switch.

It is my understanding that the B-420 bridges in Buildings B and C should connect to the wired LAN via wireless through the B-420 in Building A. The AP should then let users connect to the wireless LAN. (In essence the bridges create the network while the APs permit users access to the network.)

I am unable to connect to the AP and I don't know why. Furthermore, I'm not sure what the settings are required on the network appliances.

You've started down the right path if what you want is to connect wired LANs in all three buildings. Your B-420 wireless bridges can be configured to operate as wireless clients, ad hoc nodes, or bridges. In bridge mode, each pair of B-420's will communicate over wireless using WDS (wireless distribution system).

For example, cable all wired local area network (LAN) clients in Building C to the same Ethernet switch as that building's B-420. Then configure that B-420 to operate in bridge mode, connecting via wireless to a bridge in Building A. If the Building A bridge is cabled to the same Ethernet switch as your wired LAN's router, clients in Building C will now be able to reach the router and use it as a gateway to the Internet.

But you also have a B-3000 access point (AP) in Building A. That means that wireless clients in (or close to) Building A will be able to associate with the AP, sending traffic through the AP and onto the wired LAN -- once again reaching the router as your Internet gateway. However, the WDS network (used to link wired LANs in all three buildings) and the AP's infrastructure wireless LAN (WLAN) (used to link wireless clients to the wired LAN) serve completely separate purposes.

To link your wired LANs using wireless between buildings, use your B-420's wireless panel to set their operating mode to "bridge." Set Building B and C's B-420 peer bridge MAC address to Building A's B-3000 MAC address (usually located on the device's underside).

Next, use the B-3000's wireless panel to set operating mode to AP+Bridge. Enter MAC addresses belonging to Building B and C B-420's in the remote bridge MAC address list. At this point, any wired device plugged into Building C's B-420 Ethernet port should be able to reach any wired device plugged into your Building A Ethernet switch, including your router. But you still need to configure your infrastructure mode WLAN.

Using the B-3000's wireless panel, enter an SSID -- this is the "available wireless network" name that clients will use to connect to your wireless AP (WAP). At this point, any wireless device within shouting distance of your B-3000 should be able to browse for available wireless networks, see the SSID that you entered, and connect to it. Once connected via wireless, those clients should be able to reach any device on your wired LAN, including your router.

But I am not certain this is your target design. If you actually wanted to provide wireless client access in all three buildings, you've still got more work to do. In that case, you probably wanted to put B-3000's (not B-420's) in all three buildings, setting all to AP+Bridge mode. In that case, each building would have its own wireless LAN, which are then joined to each other over the WDS bridge. To learn more about the capabilities of your B-3000 and how to configure other settings, see ZyXEL's PDF: ZyAIR B-3000 802.11b wireless AP user's guide.

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This was last published in January 2009

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