Posted: Sun Dec 16, 2007 10:53 Post subject: Need help with WDS dropouts
I need some help troubleshooting a problem with wireless dropouts when using WDS.
Wired clients appear to be working fine, both in front of and behind the WDS bridge, but wireless clients drop off the network from time to time.
Here's my setup:
2 access points, "upstairs" and "downstairs". Same ESSID (network name). Same channel.
Downstairs: WAP54G (stripped-down WRT54G), connected to my main wired network, acting as access point only (no router/gateway, no firewall, no DHCP server). Running DD-WRT v23 SP2 micro.
I have my own router/firewall/DHCP/etc. setup and it is working just fine. All wired computers downstairs have full Internet connectivity, no problems there at all.
Upstairs: WRT54G, connected to a few wired computers that would otherwise be isolated, also acting as access point only (no router/gateway, etc.). Running DD-WRT v23 SP2 standard.
I'm using WDS to link the downstairs and upstairs nodes together. In the WDS setup screen, I have given each node the MAC address of the *other* node.
Security is WPA-PSK, with a shared password. Same password on both nodes, of course.
According to DD-WRT, both nodes can see each other just fine, with 1 entry under "WDS Nodes" on each, showing the other node, which is correct. Signal quality varies from 25%-50%, which should be good enough. I could have the nodes closer together, but I need to maximize the size of the WDS coverage area.
Both nodes pick up nearby wireless clients successfully. I see a list of wireless clients on both nodes, and they are different, with no duplication.
The wired computers upstairs, relying on the WDS bridge in order to see the Internet, also work correctly. I did a ping from wired --> wireless (WDS) --> wired, and it worked just great, ran it for several days (500K packets in total) with no dropouts.
So, I'm curious, why do my wireless clients still drop out?
They will be on the network just fine, getting good speed, good signal strength, and then just fail. Windows complains about the wireless network losing connection or getting into "limited connectivity". When doing a ping, large chunks of packets will go missing, anywhere from 20-100 packets at a time, and then come back to life as the connection re-establishes itself.
This, obviously, is maddening when it occurs, as it seems to happen randomly. It happens at least once an hour. Sometimes the connection doesn't automatically come back. The user must disconnect from the wireless network and then reconnect. Even then, it still sometimes doesn't come back immediately. Eventually, though, the network "comes back to life" and the user can connect again.
I have no problems with WPA-PSK setup or passwords, as clients can always make the initial connection and get through successfully. IP addresses are always correct, so I know it's not a problem with dueling DHCP servers or anything like that. It's just that staying reliably connected for long periods of time that is the problem.
I've also observed the same problem with Linux laptops, so know that it's not a weird Windows glitch.
Is there some bug between WDS and WPA? I hope not. I need to use WPA on this network, for security, and I don't want to use WEP.
Before proceeding with the below solution, pls check your APs for interference! Logon to both APs and do a site survey, change your Channel to 1 or 6 or 11 if you found any nearby APs which is not belongs to you.
My experience with WAP54G is that it will automatically reboot itself when running low in memory or while heavy load. This can be notice when you access the configuration page, check on the uptime! Advisable get another WRT54G or a better WRT54GL to make it a main AP for your network. _________________ WRT54GL v1.1 w/DD-WRT in WDS
WAP54G v3.1 w/DD-WRT in WDS
Before proceeding with the below solution, pls check your APs for interference! Logon to both APs and do a site survey, change your Channel to 1 or 6 or 11 if you found any nearby APs which is not belongs to you.
My experience with WAP54G is that it will automatically reboot itself when running low in memory or while heavy load. This can be notice when you access the configuration page, check on the uptime! Advisable get another WRT54G or a better WRT54GL to make it a main AP for your network.
Thanks, I checked the uptime of both routers and it's 11 days on both of them, since I last unplugged them when fixing a previous problem. So, frequent reboots aren't happening, which is good.
I did a site survey earlier, from a laptop, while both routers were unplugged, so that I could see everybody else but not myself. There's traffic on all channels, 1, 6, and 11. I took the least crowded channel, channel 1, but there is no completely free channel around here.
Change the essid on one of the wrt's this will stop wireless clients switching from one ap to the other , and is not required for a wds link.
Interesting. I kind of wanted clients to be able to roam from AP to AP, as they get out of range of one, the other can kick in. Isn't that one of the key features of WDS?
The problem I have happens even when clients are standing totally still. I don't think they would be trying to switch AP's. It's worth a try, though.
Joined: 16 Jun 2006 Posts: 36 Location: Lincolnshire
Posted: Wed Dec 19, 2007 9:06 Post subject:
WDS is great for linking lans , the downside is slower throughput for wireless clients.
If you want to keep both essids the same try using just one dhcp server , then the wireless clients wont disconnect as they try to pick up a new IP.
WDS is great for linking lans , the downside is slower throughput for wireless clients.
If you want to keep both essids the same try using just one dhcp server , then the wireless clients wont disconnect as they try to pick up a new IP.
Tom
Thanks, but I already am using only one DHCP server. I'm not running DHCP on any of my AP's. Instead, I use a DHCP server that's part of my wired LAN. So, that shouldn't be a problem at all.
I'm still getting weird dropouts. I wish I knew the cause. I've tried everything I can think of. One data point of weirdness is that it works fine from a Linux laptop, but a Vista laptop has problems. The Vista laptop keeps saying my WPA password is wrong, but it's not wrong, because it works just fine from the Linux laptop. Strange!
Joined: 06 Jun 2006 Posts: 3763 Location: I'm the one on the plate.
Posted: Sun Dec 30, 2007 8:03 Post subject:
[quote="Krellan"]
tomdidit wrote:
I'm still getting weird dropouts. I wish I knew the cause.
Cordless phone on 2.4 GHz rings ? Granny in the back room microwaving a bag of popcorn with a leaky oven door ? Neighbor with an 802.11N system pulls some bandwidth ? Most likely a Vista bug or buggy wireless driver for the Vista computer, both of which are real high on the probability list. _________________ http://69.175.13.131:8015 Streaming Week-End Disco. Station Ripper V 1.1 will do.
I'm still getting weird dropouts. I wish I knew the cause.
Cordless phone on 2.4 GHz rings ? Granny in the back room microwaving a bag of popcorn with a leaky oven door ? Neighbor with an 802.11N system pulls some bandwidth ? Most likely a Vista bug or buggy wireless driver for the Vista computer, both of which are real high on the probability list.
Nope, I'm deliberately continuing to run old ratty 900 Mhz cordless phones here, years after they should have been thrown out, just because they aren't 2.4 GHz :)
Microwaves aren't in use at the times the dropouts happen. As for neighbors, there is some interference, but not much. I ran Kismet, and saw very little usage, but dropouts were still happening.
I suspect it's something with WDS and WPA active together. The reason is the dropouts never happened before, on identical hardware.
As for my old configuration, I used to run WEP. I also didn't run WDS, and instead gave each AP a different channel number, and ran wired Ethernet manually between the two AP's in order to get them on the same network. Other than the lack of Ethernet, there is no difference in hardware setup between my old configuration and what I have now.
There were no dropouts at all, under this configuration. It worked, and users could connect to whatever AP was closest to them. However, it sucked for roaming, because they had to manually reconnect whenever they roamed out of range of one AP and into the other. Also, I don't want to run WEP anymore, as it has been cracked six ways from Sunday.
Are there any known bugs in DD-WRT regarding WDS and WPA active together?
You could switch off security and use mac filters.
Vista laptops can be a problem.
Tom
I'd like to have some security, as MAC filters by themselves are useless.
I was reading some "interesting" things about Vista. Evidently it can't speak WPA-PSK with TKIP reliably. This must be the "Wow" Microsoft was talking about. As in, wow, what were they thinking?
I tried upgrading my WDS setup to WPA2-PSK with AES, and it worked! I'm glad the old warning about WDS in DD-WRT not being compatible with WPA2 is no longer true.
Thanks for everyone's help, I think this is a Vista problem now and not a DD-WRT problem.
