Matt,
How many APs have deployed? Are you guys a full 802.11n shop?
Other than standard data usage, have you guys implemented any
specialized services such as VoWLAN, Video, and/or RFID? I'm curious
how these types of services function while operating all on the same
frequency . . .
Thanks!
==========
Ryan Holland
Network Engineer, Wireless
CIO - Infrastructure
The Ohio State University
614-292-9906 [email protected]
On Jul 29, 2009, at 1:45 PM, Barber, Matt wrote:
Hi John,
I am curious what you mean when you say “it’s just not how clients
work.” With a single channel, the clients and APs see and send
probes just like they would if you were using more channels. If
anything, the single channel helps the clients by not having to
change channel as they roam between APs.
As always, I’ll happily disclose that we have been running a Meru
11n deployment for almost two years. We do stack channels for extra
capacity, but the large majority of our APs run on the same channel
and have since the beginning.
Take care,
Matt Barber
Network Analyst
Morrisville State College
315-684-6053
From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[email protected]
] On Behalf Of John W Turner
Sent: Wednesday, July 29, 2009 1:35 PM
To: [email protected]
Subject: Re: [WIRELESS-LAN] Single Channel vs Multi-Channel
Architecture
We have been running a 4 channel plan for 3 years with ARM (Aruba)
and have had no problems. This is across 850 AP's in 100 buildings.
The single channel plan seems like a good idea, but it's just not
how clients work....
--
John W. Turner
Director of Networks & Systems
Brandeis University
----- Original Message -----
From: "Ken Connell" <[email protected]>
To: [email protected]
Sent: Wednesday, July 29, 2009 12:15:17 PM GMT -05:00 US/Canada
Eastern
Subject: Re: [WIRELESS-LAN] Single Channel vs Multi-Channel
Architecture
I don't have much experience with a single channel deployment, but
without even getting into vendor preferences or specifics I can't
see how a single channel can gain any perfomance in such an
unpreditctable and dynamically changing environment as far as other
devices, and wireless networks that will come and go probably a
daily basis with little or no control.
The channel you decide on today, may not be the best suited channel
tomorrow, and if you then need to make a change at that point, then
you've jsut come full circle and are right back where you started.
In my opinion it just makes sense to go with an automated RF type
deployment (Aruba ARM for us) and be able to sleep at night ;)
Ken Connell
Intermediate Network Engineer
Computer & Communication Services
Ryerson University
350 Victoria St
RM AB50
Toronto, Ont
M5B 2K3
416-979-5000 x6709
From: Ryan Holland
Date: Wed, 29 Jul 2009 09:04:34 -0400
To: <[email protected]>
Subject: Re: [WIRELESS-LAN] Single Channel vs Multi-Channel
Architecture
...interesting thread...
When we were making our decision 3+ years ago, we discounted Meru
primarily on scalability information in their RFP response. So
unfortunately, we did not get a chance to bring them in for a demo.
I am still quite skeptical about a single-channel architecture but
believe I understand why it is promoted: to assist devices in
roaming by creating a seemingly single BSSID. However, once we see
more devices supporting standards such as 802.11k and 802.11r, such
efforts, to me, are negated. Again, however, I have not had the
opportunity to play with this gear, so [disclaimer].
We have been deploying Aruba for sometime and have learned a great
deal about their technology, so I will caution the trusting of
intelligent radio management solutions. Instead, I would suggest one
utilize this technology while maintaining a tight supervision of it.
Using Aruba with whom I am most experienced, their adaptive radio
management (ARM) is quite powerful, as it allows for dynamic
remodeling for channel and power based on the environment. This
means that as other building tenants bring in their own wireless
systems, our network can modify its channel configuration
accordingly. Also, in the event of an AP failure, adjacent APs will
likely perceive a lower aggregate signal strength of neighboring
APs, boost their power, and thus help alleviate the loss of coverage
from said failed AP.
The reason I cautioned earlier is that many administrators simply
"turn on ARM" and leave it. Doing so is assuming the defaults are
applicable for all environments, which I would argue is not true for
most educational institutions. Examples: the range of chosen
transmit power is likely too expansive; the noise threshold at which
an AP would change channels may be too low, especially for "research
areas" like Illinois mentioned; the target coverage index may be
too low for densely deployed installations or too high for sparsely
deployed installations. Aruba is great in that administrators can
configure different ARM profiles for all these different
circumstances and use them suitably. But again, to just turn it on
and expect it to "work" can lead to false assumptions.
I would also add that there are still a lot of those that state
static channel/power assignments is the best way to go. While I
would agree that is true assuming the environment is identical at
installation as it was during survey, it is incredibly likely that
the environment will change and therefore negate the initial survey.
Because our environments are largely unpredictable, I find a dynamic
solution to be preferable. Now, if we had complete control over RF
across campus, my opinion may be different.
(Oh, and because people seem to be concerned with these sorts of
numbers: ~5,000 APs, ~40 controllers).
==========
Ryan Holland
Network Engineer, Wireless
CIO - Infrastructure
The Ohio State University
614-292-9906 [email protected]
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