hi,

I need to extend the range of my wlan with a "relaystation" that has no wired connection.
I know it's possible with WDS, but the bandwidth-reducing because of relaying is nasty.

So I would like to use 2 APs connected wiredly to each other a relaypoint (to avoid WDS)
I thought about putting one of them in STA mode and link it up to the main AP, while running the other one in AP mode and providing wifi access to clients that are too far away. .
Does this make sense?

I would then use the same sid and encryption on both wireless networks,
but of course different channels, right?
With same channels it would make no sense, I could use WDS then...

This is what I mean:

Client~~~Channel X~~~~AP---STA ~~~ Channel Y ~~~~AP(with internet connection)

Does this work? What about roaming for clients, even with different channels(same sid, same encryption)?
I don't need full roaming, there can be connection loss when leaving an AP's coverage.
It would be quite enough if clients are able to connect to both networks with the same configuration and take the one that is nearer when establishing a connection.

hmm... I'm quite sure some of you know this...
so a similar situation would be:

take a routerboard, take 3 minipci wlan cards and connect them to 3 sector antennas.
do this instead of a setup with 1 minipci connect to a omni antenna.

now, how to set this up, to act like the 1minipci with the omni, but with a lot more range&power.
again, using the same essid and encryption is needed for sure, but what about the channel?
would you use different channels or the same for the 3 minipcis with the sector antenna..

what is the client behaviour if there are multiple stations with same essid on different channels?

people seem to focus on this "bandwidth reduction" problem as if it's a wds issue. the only issue is transmitting traffic on the same wireless interface it's received on. best performance for relaying would be a device with two wireless interfaces, one connecting to the other ap with wds, and the other serving wireless clients.  you seem to know this, but it really gets to me. anyway.

as to channels, a client will connect to the closest ap with the desired essid regardless of which channel it's on. the aps have different macs, and are seen and associated with seperately on the client (usually below the level of user interaction, on windows at least). only reason to force them to be on the same channel would be a large repeating wds setup, which would of course be rather silly in this case

indeed with two radios on the relay, i can get stable 21mbps bandwidth all the way to the root node.

thanks guys, so it seems that I have been right...

I did some testing myself and most wireless-client managers really do not care about the channel and mac of the AP, as long it runs the same SSID (at least windows xp sp2 doesn't care...)
so my clients are connecting correctly to the network that has better signal.. fine!

however, I wasn't able to achieve "dynamic roaming", meaning:
if a client has associated with an AP, he will only disassociate when losing connection,
not when there is another AP with same SSID, other channel and better signal
(what of course may happen if you move around with a connected client notebook...)

but that's not a problem for me..

I have done a dual-radio repeater station using 2 WRT54GL units several times. It's easy and effective.

Run a first pair of WRT54GL in plain WDS bridge mode to each other. They are on same channel let's say channel 1, and talking only to each other.  Ideally use MAC filtering and WPA-PSK security, lock out clients, this pair is just for backhaul.  These have high-gain directional antenna targetting each other.

Now if you have local hard-wired clients attach them to LAN ports and off you go. If you couple another WRT54GL to the LAN you could use it on Channel 11 and with different SSID and encryption setttings to service local clients.  So with a total of 3 very inexpensive WRT54GL units, you have built an effective and reliable network, no highly-variable latency and other issues like with trying to do single-radio repeater.

(Last edited by vincentfox on 17 Jul 2007, 04:37)

I did some extensive testing on this idea, and well, I'm very disappointed, here is my basic setup:

AP1(AP) ~~~~{wifi1, signal lvl: ~50, ch1} ~~~ AP2(STA)----AP3(AP) ~~~{wifi2, ch10}~~

I used 2 notebooks for testing, here are my results, I'm not happy with it,
so I hope someone can explain this to me :-(

1) Notebook1 connected to AP1 wired, Notebook2 connected to AP3 wireless
Notebook1 ---- AP1(AP) ~~~{wifi1, signal lvl: ~50} ~~~ AP2(STA)----AP3(AP)~~{wifi2, signal lvl: ~50} ~~ Notebook2

The whole thing was done to get full speed in these cases, but unfortunately speed is bad, only 800KB/s max. between Notebook1&2 :-(
But both wifi-links are at full 54mbps. Does anyone have an idea, why I don't get full speed?

To make sure, there is no problem with each of the wifi-networks, I did the following tests:
2) Notebook1 connected to AP1 wired, Notebook2 connected to AP2(STA) wired
Notebook1 ---- AP1(AP) ~~~{wifi1, signal lvl: ~50}~~AP2(STA) ---Notebook2

I'm getting full speed in this case, about 1,4MB/s max..... as expected...
so there seems to be no problem with wifi1

3) Notebook1 conntected to AP3 wired, Notebook2 connected to AP3 wireless
Notebook1 ---- AP3(AP) ~~~{wifi2, signal lvl: ~50}~~~ Notebook2

Also full speed, about 1,4MB/s max... no problems with wifi2.

---------------------------

As you can see, both APs are able to transfer with 1,4MB/s, just at the moment when the transfer has to go through both networks, the speed drops dramatically.... but why?? I can't see a reason, I'm using channel1 & 10 and the AP(STA) is connected with a directional antenna.. so I don't see any frequency-interferences here?! May be I should give routing a try instead of bridgeing ?! could that be a reason?
I'm thinking of using client-mode on AP2 instead of STA...

any help is appreciated...