WDS, network extending, and 2.4Ghz versus 5Ghz

Question

Level 2

391 points

WDS, network extending, and 2.4Ghz versus 5Ghz

Well, having spent a lot of time yesterday to set up 2 new AEs, I came away with some questions;

It appears like it it NOT possible to create or participate in a WDS network on the 5Ghz spectrum - the only choices are in the 2.4. Why is that?

Same for extending the network - it is not clear to me what the difference to WDS is. In any case, this seems to stay in the 5Ghz range (that might be the only diff?), but enables a as well as n).

However, I had horrible results - by extended station would loose connectivity to the base every few minutes - and they are maybe 20 feet apart.

I now have both setup on seperate segments (5 and 2.4), with the 2.4 bridging, so it's well - but I wonder if anyone else has tried this, has any experience, any insight.

WDS or extending - at least for me, didn't work sufficiently (I wanted to extend the network to also provide an ethernet converter for some wired devices in another room).

Cheers,
dan

Mac Pro 3Ghz, 4GB, ATI 1900XT, ACD 30. MacBook Pro 2.33, 3GB, Mac OS X (10.4.8)

Posted on Feb 8, 2007 9:37 AM

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Answer 1

Royal

Level 2

365 points

Feb 8, 2007 9:46 AM in response to dosers

I think the reason that you can't do WDS in 5GHz is that WDS requires a static channel, but in 5GHz operation, you sometimes have to switch channels if you run into radar.

Network extension may have a similar limitation.

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Answer 2

dosers Author

Level 2

391 points

Feb 8, 2007 10:06 AM in response to Royal

Royal,
interesting - and that might / would explain it.
It also locks you into WPA2 (I would have used that anyway - but it's odd).

Back out then - has anyone done WDS or extending with the new AEs and had different (better) results than me ?! 🙂

Thx,
Dan

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Answer 3

Feb 8, 2007 11:15 PM in response to dosers

WDS is intended for 802.11 g or b, which is why you can only use it in 2.4Ghz.

You can extend your 802.11n network in a much simpler way. Just have one of your base stations create a network and check the check box "Allow the network to be extended".
On the 2nd base station select "Extend a Network" in the popup menu and enter the network name you created with the first base station. You don't need WDS at all in this scenario.

This works for both 2.4Ghz & 5Ghz, but you have to select "802.11n Only" as your config.

Now regarding performance I'm a bit baffled...
In 2.4 Ghz I get an incredible good signal. Even 60 feet away in another room I still have a full signal (mixed mode or 802.11n only).

However when I select 802.11n 5Ghz, I barely get a signal at all in that room.

Pretty strange. Can someone explain why?

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Answer 4

SAHafeez

Level 1

24 points

Feb 8, 2007 11:29 PM in response to Killko Caballero

It is very simple. 5Ghz does not go thru stuff as well as 2.4Ghz. The larger the number re-Ghz the shorter the distance and ability to pass thru walls, etc (Up to a point). There is a full physics reason for this if you want to look it up. I am to lazy to detail it.

The 1st wireless stuff was 802.11a (5Ghz). There is a reason that 802.11b won.

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Answer 5

Feb 9, 2007 1:37 AM in response to SAHafeez

Yeah, I saw that.

Here's a pretty detailed explanation I found:

http://wifinetnews.com/archives/007336.html

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Answer 6

Feb 9, 2007 6:15 AM in response to Killko Caballero

I thought your method of "Extending" the network only worked if the AirPorts were wired together? If not, then what's the purpose of WDS?

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Answer 7

Feb 9, 2007 9:16 AM in response to Bob Antoniazzi

I don't think so. In Apple's manual "Designing Airport Extreme 802.11n Networks",they describe your scenario as "Roaming". In this case each base station creates a wireless network with the same name.

Extending an 802.11n Network is the simplified equivalent of WDS for 802.11n networks.

This is described in pages 39-46 in Apple's manual that yo can download from their support site.

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Answer 8

Feb 9, 2007 9:37 AM in response to Bob Antoniazzi

Btw, you can download the manual here:

http://manuals.info.apple.com/en/DesigningAirPortExtreme802.11nNetworks.pdf

I'm pretty sure it works. I have 2 base stations deployed the way I described, and from my wireless connected MacBook Pro, I can access different ethernet wired file servers on each base station.

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Answer 9

dosers Author

Level 2

391 points

Feb 9, 2007 9:57 AM in response to Killko Caballero

Interesting,
and that makes sense.
And, I am seeing the same thing with 5Ghz - in fact, I tried to extend my 2 stations - but didn't have good results.

I extend fine, the extend-station finds the base, all is well. But very shortly, the extend station seems to crawl - when I am associated to it (versus the main, or both - which is possible) internet / browsing slows to a crawl, and after 1 hour, sometimes less, communication with the base with be lost altogether - no internet browsing.

When I look at performance in the airport uitlity, all seems fine though with a rate of 180 or 270 or what have you. I just don't get it - is extending buggy or not quite there yet? Using with WPA2 (but you only have that option with extending).....

I even swapped stations, reprogrammed, same thing (i.e. so it's not a bad station), base is fine, extend will be fluctuating greatly (as sometimesit gets a bit better over time).

Cheers,
Dan

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Answer 10

dosers Author

Level 2

391 points

Feb 9, 2007 1:31 PM in response to Killko Caballero

So, that makes me wonder another thing;
To do 'extending' (not WDS), you need to have the base on 5Ghz only, n only.
I can enable (and want to) WIDE band.

On the extended station, I have no such options anymore. THe extended station is N AND A - that is even though the base is 'n' only, the extended station has a enabled (and not defeatable) as well.
Furthermore, no option for wide band (which is available on 5Ghz). Does that mean it's on by default, as the base station is, or it cannot be turned on, on the extension?

Cheers
dan

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Answer 11

Feb 10, 2007 12:03 AM in response to dosers

I had a lot of problems with 802.11n in 5Ghz. While theoretically I get 300 Mbs throughput, in reality as soon as I move a bit away from the station the performance drops.

I ended up switching to 802.11n only in 2.4Ghz. I can still extend the network the same way, and the performance is overall much better.

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Answer 12

dosers Author

Level 2

391 points

Feb 10, 2007 1:07 PM in response to Killko Caballero

Interesting !
And too bad - I mean, that is defeating at least SOME of the purpose of 'n' a bit; the mimo operation, the using a (in theory) less crowded spectrum, at least in the US.
In the end, there was a reason 'a' never made mainstream (and it was intended for high-speed, short range). I guess that's not Apple fault, or problem alone, but it's disapointing for sure.

I might try 2.4Ghz n as well - if that gets faster real throughput that n on 5Ghz, using wideband dual radio - wow......

Thanks,
Dan

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Answer 13

Ryan3587

Level 1

45 points

Feb 12, 2007 7:57 PM in response to dosers

So, let me ask you guys this as I am still figuring out my new network and want to get the MAX speed and the MAX smoothness out of it! Right now my internet is FAST! I am experiencing no real issues. My only real issue is that both my "N" stations are WDSed at only 54Mbps. Bare with me as I explain my setup so you can help me figure out the best setup/settings for my system...

Comcast 4MB Internet to a Cable Modem to a Vonage Hub to my AirPort Extreme 802.11n (Living Room). I currently have another Extreme 802.11n in my office in which two printers and an external hard drive is connected to. Now, the one in my office is connected to the one in the living room via WDS/Bridging.

Would just "extending" allow this network to work at 5Ghz? What about dual band using an Express?

I have a MacBook Pro "N" and a MacBook "G" that will be connecting to the network, with many times the MacBook being OFF the network.

I also have two AirPort Express "G" devices collecting dust.

What are my best option(s)?

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Answer 14

dosers Author

Level 2

391 points

Feb 12, 2007 8:26 PM in response to Ryan3587

Hi,
correct - you need ⚠ to EXTEND the network to operate on 5GHz. If you use WDS, you can only use 2.4Ghz. That still allows 'n' - at faster than 54, but won't allow wide channels (mimo). It WILL allow a and n clients - and while not huge, the overall speed will go down if an 'a' client joins.

The G will also slow down the overall network somewhat.

THe best case, with maximum speed - but additional cost would be a segmented network:
Have a 5Ghz, n-ONLY base. Then hand another airport (does not need to be the new n) off it VIA ETHERNET ⚠. Make that BRIDGE ips, versus assigning it's own. Now have G and b clients join that network, while n only client will join the other network. They will be routable and can see each other, as they will exist on the same subnet (since the 2nd station is bridging).

You can then, if you want, extend ⚠ EITHER network - but if you do, that would require a 3rd (total) station.

SInce you have airport G's collecting dust - this might be cost neutral to you after all:

Use 2 n (extend one with the other), and one 'old' G- hanging of the BASE station via bridging - and have the best speed of both segments of your network.

Does that make sense ?! 🙂

Cheers,
Dan

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Answer 15

Ryan3587

Level 1

45 points

Feb 12, 2007 8:32 PM in response to dosers

Kind of makes sense, but not really... My only real question is this... Will I lose the capabilty of using the printer and hard drive that is connected to my other Extreme in the other room? I know I can Ethernet an Express off the Extreme that is connected directly to the internet, but if I turn WDS off, keep the Bridge, and Extend the network, would I still be able to access those devices on the USB Hub that is wirelessly in another room?

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