Jason, I wholeheartedly agree. We here at Liberty University spent a year evaluating wireless & NAC solutions. We chose to move from Cisco "fat" APs & Clean Access to Aruba's wireless & ECS NAC solutions.
The real challenge is in dense environments. Meru's "single channel" becomes "channel stacking" aka multi-channel to provide additional bandwidth. You then have the client roaming issues again. Also, you cannot "steer" clients to load balance the clients across available resources. Aruba's ARM 2.0 has many options in this situation and solves many of the issues that Meru's architecture solves. With a single channel architecture, you are "stuck" if some interference appears in that RF range. The system may be able to change to another channel, but that WOULD CAUDE *all* the clients to roam. In a multi-channel architecture, only a small number of clients would be affected. There is obviously a reason why Meru is the _only_ vendor with single channel. All the others (including the largest players) use a multi-channel solution. If Meru's solution is so great, you would see others with single-channel too, even if they needed to license technology from Meru. Bruce Osborne Liberty University From: Jason Appah [mailto:[email protected]] Sent: Wednesday, July 29, 2009 1:44 PM Subject: Re: Single Channel vs Multi-Channel Architecture I agree wholeheartedly, the Aruba ARM works quite nicely, recently the neighboring hospital turned up its radios, and ARM switched us out without missing a beat. We reviewed Merus's devices and liked the approach, but were less than wowed with the completeness of the feature set. In the end we choose Aruba for four reasons: Price - pretty self explanatory Performance/deployment - (this was identical in most and in many of our use cases better than Meru) Feature Set - Aruba has obviously spent many hours actually listening to and implementing user centric changes, I don't know of a more feature rich wireless solution Support - Aruba has in many occasions been proactive, where I have posted a question to this forum and others to actually go out of their way to contact me to help me fix a problem, in some instances where the problem wasn't even Aruba's at all... We haven't looked back. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:[email protected]] On Behalf Of Ken Connell Sent: Wednesday, July 29, 2009 9:15 AM To: [email protected] 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]<mailto:[email protected]> ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
