...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]
**********
Participation and subscription information for this EDUCAUSE Constituent Group
discussion list can be found at http://www.educause.edu/groups/.
