Autonomous dual-radio APs: VSCs run on both radios?

[ndoudna]

I'm preparing to configure some MSM 430s in autonomous mode, that will have one radio configured for 2.4GHz and the other for 5GHz.

Do the VSCs run on both radios?  If so, how does the 5GHz band get selected -- is that left to the client?

Before you jump in with "band-steering!" , the MSM422 I'm testing on doesn't have band-steering as an option in autonomous mode, I don't know yet about the MSM430.  But the question is: without band-steering, how is that 5GHz band used?

Another option is to set up one VSC for 2.4GHz and one for 5GHz, but my MSM422 in autonomous mode doesn't have the VSC bindings that a controller offers, don't know about the MSM430.

So how are two bands used with one VSC, is it just left to clients to decide which?

thanks,

noemi

[Fredrik Lönnman]

A VSC can run on both radios and yes, its up to the client to decide 2.4 or 5GHz so YMMV. Even with band steering its ultimately up to the client, but then the AP can at least to some degree influence the choice.

[ndoudna]

Thank you!

Related question that arguable deserves its own topic: On a dual-radio AP, is it best practice to configure each radio in a different band? If they're both in 2.4GHz, they can interfere with each other, so one should run in 2.4 and the other in 5.  Or is there internal shielding or something to mitigate interference between the two radios?

thanks!

noemi

[BGraham_1]

It would be nice in some circumstances to have both radios on the smae band, but the software doesn't allow it.

Bob

[ndoudna]

>It would be nice in some circumstances to have both radios on the smae band, but the software doesn't allow it.

Yes it does, at least my MSM422 in autonomous mode accepted 802.11b/g on both radios, and I'm pretty sure it did in controlled mode too.

(I tried this because I came across a recommendation by an HP systems engineer not to put the two radios in the same band, suggesting that not only can it be done, but it is commonly done if not ideal.  Other references suggest that people think doing so will increase (double, even!) throughput.  It'd be an interesting test to compare two radios in the same band vs. one.)

thanks,

noemi

[BGraham_1]

My mistake.

I have been working with the MSM460s lately. It will not both radios to be on 5GHz simultaneously.

Bob

[Fredrik Lönnman]

BGraham_1: The 466 will do 5GHz on both radios. I'd generally recommend against it on the 2.4GHz band though, its way to crowded anyways.

[BGraham_1]

Hi Fredrik,

I agree. The 466 can have both radios configured for 5GHz, probably because the external antennas allow placement so they won't bleed over. The 460 will not allow both radios to be configured for 5GHz, at least as of 5.7.0.2. Hopefully that will change.

This would allow the 460s to be used in areas where there is a high density of users (I am thinking 500 or more), without overlapping channels.

Bob

[Fredrik Lönnman]

Yeah you're right about the external antennas, and for that reason I dont think that 460 will ever get dual 5GHz.

[ndoudna]

OK, got my hands on an MSM430.  Radio 1 only has one wireless mode "802.11n/a", and Radio 2 has "802.11n/b/g" and "802.11n/a".

But all 3 of the MSM430s I'm trying to deploy on autonomous mode are broadcasting only in the 5GHz band -- none in the 2.4GHz?   Confirmed with inSSIDer.  I can't find any setting in the Wireless section nor the VSCs that would cause this.  Any ideas??

thanks!

noemi

[ISoliman]

Under the VSC there is an option to broadcast the SSID in both radios, default is on Radio 1 only, you will have to change that.

[ndoudna]

>>

Under the VSC there is an option to broadcast the SSID in both radios, default is on Radio 1 only, you will have to change that.

>>

Thanks, finally found that - "Radio 1 AND 2" has to be selected in every VSC.

The MSM430 running 5.5.2 in autonomous mode has its defaults set up like this:

  - Radio 1 is in 5 GHz

  - Radio 2 is in 2.4 GHz

  - VSCs transmit/receive on Radio 1 only.

So defaults add up to : don't broadcast in the 2.4GHz band.  (This must be a plot by the FCC to reduce crowding in 2.4!)

thanks,

noemi