Unfortunately, sometimes things aren't so easy. So here are a few troubleshooting tips if you can't get your WDS link up and running.
- If your ping test comes up with timeouts, wait a little longer and try again. I've found that some products seem to take awhile—up to a minute in some cases—to establish a WDS link, even after they appear to have fully booted.
- Next, double check the settings on both APs. In particular, make sure you've entered the MAC address of the opposite end of the WDS link in each AP's allowed MAC address list. Also make sure that the MAC addresses themselves have been correctly entered. You don't have to worry about confusing O's and zeros or I's and ones, since MAC addresses use only the letters A through F. But I've been bitten more than once from reading B's as 8's (and vice versa)!
- Then try power cycling both APs. Power down both, then power up the local (LAN-connected) one first and wait for it to come fully back up. Then power up the remote AP and wait for it to fully reboot. Then try the ping - again making sure you wait long enough before trying.
- If you've tried using WEP to secure the WDS link and it isn't working, try running with no encryption. Using WEP with 802.11n gear is going to knock your throughput down to 802.11g rates anyway. And as noted earlier, you can't use WPA or WPA2, since they use dynamically rotated keys.
If none of these steps work and you're using APs from different manufacturers, you unfortunately may have found two products that won't work together. In this case, there's not much you can do besides trying another product, preferably another one of the same model for best chance of success.
Example 2: WDS bridge pair
There are more routers without built-in WDS than there are with. So you may need to resort to using a pair of WDS-enabled devices to get your bridge or repeater up and running. In my case, I found that the Atheros-based WNDR3700 didn't play very nicely with the Ralink-based EnGeniuses. So I had to pair up the EnGeniuses to get a reliable WDS connection, as shown in Figure 10, so that I could do some throughput testing.
Figure 10: WDS bridge pair configuration
To set this up, I converted an EnGenius ESR9850 [reviewed] to an access point and assigned it an IP of 10.168.3.98. Then I entered each router's 2.4 GHz radio MAC address in each other's WDS MAC address list. I had to use the 2.4 GHz radio, because the ESR9850 is a single band router.
I also set both EnGeniuses to Channel 1, since the WNDR3700 was using Channel 11 (in 20 MHz bandwidth mode, of course). The ESR9850's settings are shown in Figure 11.
Figure 11: EnGenius ESR9850 WDS settings
Note that the ESR9850's Mode is set to WDS. But there is also another selector up at the top of the page. You want to leave it in the default AP Router Mode, since changing it to the Repeater Mode setting disables WDS. You set the Repeater Mode to link the ESR9850 to routers that don't support WDS.
Almost as soon as I finished saving the settings on the second AP, the lights on both and the switch that was linking them starting the continuous flashing that indicates the network storm caused by a successful WDS link.
I then unplugged the ESR9850 and was able to ping it and reach its admin pages without even having to reboot. Just shows you what using a WDS pair with the same manufacturer chipset will do!