Here is a response I received from Aruba Engineering:
Bruce,
I have heard this from some of my other customers as well. The basic issue
comes down to the physical properties of the 5GHz wave vs. the 2.4GHz. The
lower frequency (2.4) will be able to travel through air and walls and even
"bend" around corners better than the higher frequency 5GHz wave. For this
reason at the edge of an AP's coverage area the 2.4 signal will be better
quality than the 5GHz. With band-steering enabled we will keep the client on
the 5GHz radio despite a better performing 2.4 signal being available.
I would prefer to keep band steering enabled and design the RF coverage based
on the 5GHz coverage.
You can add an AP 105 and set the b/g radio as a full time air monitor or you
can consider a single radio AP (the AP-93) to provide 5GHz coverage only to
these areas where the 2.4GHz can reach but the 5GHz does not.
Thank you,
Bruce Osborne
Liberty University
-----Original Message-----
From: Ethan Sommer [mailto:somm...@gac.edu]
Sent: Wednesday, August 11, 2010 3:30 PM
Subject: Band Steering?
We are upgrading part of our network using Aruba AP-105s and a pair of
3600 controllers.
We've found an annoying problem when we have band steering turned on.
We've create two SSIDs. Lets call them BandSteering and NoBandSteering.
When users are relatively close to an access point, they can connect to either.
My MacBook will usually connect using 2.4 Ghz on NoBandSteering and will always
connect using 5ghz to BandSteering. When a user is further away from the
access point, however, they can connect fine to NoBandSteering (obviously it is
slower than when they were closer) but can't connect at all to the BandSteering
SSID. It doesn't fail back to 2.4ghz, and the clients don't recognize that they
can't connect and connect to NoBandSteering if that's lower in their preferred
networks list.
The effect is that, understandably, users will select the NoBandSteering SSID
because it is more reliable. (Even though it is slower in most cases.)
Aruba suggested that I try setting the 5ghz ARM profile to always max out the
5ghz radio, which helps some but does not eliminate the areas where 2.4ghz
works and 5ghz doesn't.
So, my questions are:
1. Are people using band steering?
2. Have you found the same problem?
3. Is there a way to fix it? (Other than turning off bandsteering.)
4. I suppose a related question is, is there a way to make client computers
prefer 5ghz more?
I guess we'll probably just not use band steering if we can't find a solution,
but it would be a shame not to better utilize the 5ghz spectrum better.
Thanks for any suggestions!
Ethan
--
Ethan Sommer
Associate Director of Core Services
Gustavus Technology Services
somm...@gustavus.edu
507-933-7042
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