Wireless Access

Hi,

 

In one of our dorms, we've installed an AP-93h, for every two rooms, totalling 40. So two rooms (4 students) would be sharing an access point. 

 

Currently, each AP-93h radio is set to 2.4GHz being that the unit has only a single radio. I'd love for those students who have 5GHz-capable devices to be able to access that band whenever possible. If I turn on the Mode-Aware feature, will the controller switch some of the APs to 5GHz? The manual is vague on this topic.

 

Thanks for the help.

Mode-Aware only Turns off Radios when there is too much coverage.  It does not change bands on a single-radio AP, no.

 

So there's no way of dynamically switching the radio's band depending on need?

There is no way of doing that.  Can we assume that if a user is 5ghz capable, he is also 2.4ghz capable?

 

yes definately.  I was just wondering on how we can get our dorm to have both bands available, as needed with the 93h.

I would advise you that if you have 4 students using 1 2.4ghz radio, you should be good.

 

I have not tried this myself but I will be testing out 93h for use in dorm rooms in January,  the Aruba user guide does indicate that ARM and modeaware can switch the ap from 2.4gz to 5ghz if it doesn't see available 2.4ghz channels but does see 5ghz ones as available.  So it wont look at the user device and pick the channel but it will put some of the APs onto 5ghz.

 

 

From the ArubaOS 6.1 user guide starting at the bottom of page 179.

 

""

Aruba recommends using the multi-band ARM assignment and Mode Aware ARM feature for single-radio
APs in networks with traffic in the 802.11a and 802.11g bands. This feature allows a single-radio AP to
180 | Adaptive Radio Management (ARM) ArubaOS 6.1 | User Guide
dynamically change its radio bands based on current coverage on the configured band. This feature is
enabled via the AP's ARM profile.
When you first provision a single-radio AP, it initially operates in the radio band specified in its AP system
profile. If the AP finds adequate coverage on multiple channels in its current band of operation, the modeaware
feature allows the AP to temporarily turn itself off and become an AP Air Monitor (APM). In AP
Monitor mode, the AP scans all channels across both bands to verify that each channel meets or exceeds its
required level of acceptable radio coverage (as defined by the in the ARM profile).
If the AP Monitor detects that a channel on the 802.11g band does not have adequate radio coverage, it will
convert back to an AP on that 802.11 channel. If the 802.11g band is adequately covered, the AP Monitor will
next check the 802.11a band. If a channel on the 802.11a band lacks coverage, the AP Monitor will convert
back to an AP on that 802.11a channel.

 

""

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@mverlis wrote:

I have not tried this myself but I will be testing out 93h for use in dorm rooms in January,  the Aruba user guide does indicate that ARM and modeaware can switch the ap from 2.4gz to 5ghz if it doesn't see available 2.4ghz channels but does see 5ghz ones as available.  So it wont look at the user device and pick the channel but it will put some of the APs onto 5ghz.

 

 

From the ArubaOS 6.1 user guide starting at the bottom of page 179.

 

""

Aruba recommends using the multi-band ARM assignment and Mode Aware ARM feature for single-radio
APs in networks with traffic in the 802.11a and 802.11g bands. This feature allows a single-radio AP to
180 | Adaptive Radio Management (ARM) ArubaOS 6.1 | User Guide
dynamically change its radio bands based on current coverage on the configured band. This feature is
enabled via the AP's ARM profile.
When you first provision a single-radio AP, it initially operates in the radio band specified in its AP system
profile. If the AP finds adequate coverage on multiple channels in its current band of operation, the modeaware
feature allows the AP to temporarily turn itself off and become an AP Air Monitor (APM). In AP
Monitor mode, the AP scans all channels across both bands to verify that each channel meets or exceeds its
required level of acceptable radio coverage (as defined by the in the ARM profile).
If the AP Monitor detects that a channel on the 802.11g band does not have adequate radio coverage, it will
convert back to an AP on that 802.11 channel. If the 802.11g band is adequately covered, the AP Monitor will
next check the 802.11a band. If a channel on the 802.11a band lacks coverage, the AP Monitor will convert
back to an AP on that 802.11a channel.

 

""

---

Yes.  All of that is true and correct.

 

The one thing that it does not do, and this was Derbystar's question, is sense if a device supports 802.11a and changes to that channel.  All AP93Hs start on the 2.4ghz band.  If it does not sense there is too much coverage, it will never leave it.  You also do not want to worry about it changing to 5ghz and blackholing your 2.4ghz devices, so I would NOT enable ARM Mode Aware on a single radio device.

According to the manual, the AP will switch from 2.4 to 5 if it determines that the 2.4 band is congested? Am I understanding this correctly?

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@derbystar16 wrote:

According to the manual, the AP will switch from 2.4 to 5 if it determines that the 2.4 band is congested? Am I understanding this correctly?

---

No.  If too many of your access points are broadcasting your networks on the 2.4 it will switch. It is designed to remove some access points from the equation when you have way jtoo much coverage.  It does not work well with a single band AP, because it does not factor in the bands of  the clients that are in the area.  I would go as far as to say it should not be used in a single band AP deployment because the algorithm requires a bit of fine tuning and that is not the environment that it was intended to deal with specifically.

Okay cjoseph. Thank you for the help. It's greatly appreciated.

I know I'm resurrecting an old thread here, but I'm wondering if you have changed your opinion on this.

 

I have some grossly overprovisioned dorms, with one 93H per room, some of them back to back and others not. Mostly double rooms, so about 6 devices per AP normally. What we did originally was alternate 2.4/5 down the hall, and let ARM sort out channels and power. We found that we had to switch some additional rooms to 5 because the interference made the 2.4 band useless.

 

So 3 years and 3 code releases later, do you think this an application which would benefit from mode aware ARM? 

 

Andrew

You could certainly try that. Mode aware is designed not to shut off "edge" APS. You do have a greater chance of creating coverage holes with single radio APS, however.

Have you tried to reduce the max TX power in the ARM profile for 2.4ghz to 6 or 3 first?

Your other option is to set the ARM assignment to "Multi Band", where it will assign single-band aps to 2.4 and 5ghz bands. http://www.arubanetworks.com/techdocs/ArubaOS_64x_WebHelp/Web_Help_Index.htm#ArubaFrameStyles/ARM/Multi_Band_ARM_and_802_1.htm

 

 

I was planning to use both.  Enabling multi-band requires mode aware ARM anyway.

 

I've been testing this in an empty dorm today, and I am seeing 2.4 radios both shutting off and moving already.  Airwave gets a little confused - it shows them as abgn radios when they shut off. :)

I've only gone as far as 9 on 2.4.  Should I still keep the max 6 dBm higher?  So 6/12 instead of 9/15?

 

One thing that just occured to me would be letting the ARM turn off 2.4 radios to find the heavy CCI areas, then assign them to the 5.0 profile by hand to avoid coverage holes.  Also maybe just run mode aware for a couple weeks after move in then turn if off once thing are settled.

 

Andrew

 

You should try arm multi band, then.

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@cjoseph wrote:
You should try arm multi band, then.

---

Instead of or as well as reducing min power to 6?

Only one at a time.

I have some results to share.  Out of 700 APs, 125 have now shut down and 110 have moved from 2.4 to 5.0.  I'm still seeing some bouncing around as things settle, but it looks promising so far.