Using WDS to create a Wireless Bridge/Repeater

The term WDS (Wireless Distribution System) might be a familiar one if you have meddled with standard wifi routers/access points that are available nowadays. The concept is quite simple – the system enables the router/access point to act as a bridge or a repeater. Now as simple as it may sound, trying to get WDS working to extend your wifi network or to bridge your wifi to a wired network is not considered nearly as easy as it sounds.

It all started when I wanted to extend my home wifi network to the living room where I have my NAS and an Android based device running XBMC, both of which don’t have wifi capability. So I needed the wifi to be bridged to enable a wired network as well. Since the signal in the living room wasn’t great, extending the wifi made sense. What better than using one of the old routers I already had, to get this done right? So began the hunt for a hack. The more I looked on the internet I could not get a simple set of instructions which told me how to get this done. There were many articles elaborating on the concept like this one but nothing clearly said how to do it. Yet alone most of the discussions suggested the setting up WDS was most unlikely under many different conditions.

I had to give it a shot. So I took out three different models of the old routers I had and started messing with them. Changing the settings on them and trying different levels of changes to get them working. It didn’t take long before I could get a elaborate setup working that utilized WDS. However this was quite tricky and I picked up a few things on the way. So here it goes.

Following tips are based on the assumption that two routers/access points are used to extend and bridge a wireless network. Both devices are expected to have WDS capability.

1. Set the IP of both devices in the same subnet

Set static IP’s for both devices which belong to the same subnet. If you set the main device (lets call it AP1) to have the IP 192.168.1.1, you can set the secondary device (lets call it AP2) to have the IP 192.168.1.2 or something similar. In this case we will setup AP2 to extend the network from AP1.

2. Setup only one DHCP server

If you require a DHCP server in your network it should ideally be setup on AP1. Disable the DHCP server on AP2. If AP2 supports DHCP relay, you may want to switch that on. Once you’re done with the full setup, one DHCP server should be able to assign and manage IP’s for all devices in the network.

3. Enable wifi and set the SSID

Enable wifi on both AP1 and AP2. The SSID of both AP1 and AP2 can be same or different. This doesn’t really affect the WDS setup since WDS uses your BSSID (the MAC address) to identify the devices. This decision depends on how you want to identify your network. If you want the wifi repeating to be smooth and you actually want to see your whole network with one SSID then you set the same SSID on both AP1 and AP2. If you want to identify AP1 and AP2 separately then you would want to assign two different SSIDs. What I did was have different SSID’s when setting up the network and then once I was done I switched both AP’s to the same SSID.

4. Set your wifi security to WEP

Set the wifi security on both AP1 and AP2 to use WEP. Also set the authentication to Open Authentication with a 128bit encryption. The authentication keys on both APs must be exactly the same. It’s essential that all settings be exactly the same on both APs.

5. Other wifi settings

Like I said, successfully setting up WDS to work means matching the settings on both AP’s to work the exact same way. If you have problems in getting WDS to work this is one area you can explore and tweak. As a thumb rule avoid having settings that are not absolute and can change. What I mean here is settings that are set to “Auto” or set to a range of values from which the AP can decide to choose such as “802.11b/g/n”. Following are a few of wifi settings you have to look into.

  • Wifi Mode – The mode has to be same on both APs and must be an exact value which is either 802.11g or 802.11n. If all your devices and both the APs fully support 802.11n, you can go ahead with that. However if you have difficulties getting it to work you can switch to 802.11g which has a better chance of working
  • Channel – The channel has to be the same. Having the channel set to Auto is not going to work. You can use a tool to check which channels have the minimum interference in your environment and pick the best channel. Set the channel to the same value on both AP’s.
  • Transmit Power – This shouldn’t ideally affect, however having this set to 100% on both AP’s will let you achieve the best range.

6. Set the WDS settings

Enable WDS on both APs. Depending on the device rest of the settings can vary. It essentially boils down to assigning the MAC address/BSSID of the devices to one another in the WDS settings. So in the WDS settings of AP1, you will need to assign the BSSID of AP2 and in the WDS settings of AP2, you will need to assign the BSSID of AP1. Different devices allow you to do this in different ways. You might see one of the following methods in each of you AP’s WDS settings.

  1. You may have to select the SSID of the other AP from a list (upon scanning for available networks).
  2. You may have to select the SSID of the other AP from a list which will reveal the BSSID.
  3. You may have to type in the SSID of the other AP
  4. You may have to type in the BSSID of the other AP

If either of your AP’s use method 1 or similar, you may have to have different SSID’s for AP1 and AP2 to ensure you can select them.

7. Set the correct security settings for WDS

Some devices require you to select the wifi security settings when setting up WDS. If this is the case you will need to put in the exact same settings you did in tip 4.

8. Don’t keep the APs too close to each other

When you are setting up the APs try and keep them away from each other. Keeping the APs too close to each other can cause interference which may not let either of the APs to perform.

There may be other factors that matter when it comes to setting up your WDS which I would love to know about as well. If you do find any other tips that may be useful please write them in comments section. Hope this helps someone save some time 🙂

Drawing network diagrams can be quite helpful when setting up even a simple network. Creately can be a very useful tool for drawing network diagrams. Give it a shot, its free to use.

Advertisements