Hi Everyone, Just wanted to weigh in on this conversation. We went through this same process at Gordon College about 4 years ago. We looked at Meru, Trapeze, AirSpace and Aruba. During this process, there were no independent studies or analysis of anyone's product. Gordon College pilot's any new technology. Our pilots run between 30-60 days. We also rely on analysis by Network Computing, Gartner and Tolly. Typically, they do a very good, non-bias, review of products and technology. Next we look at the company and the amount of $$ they spend on R&D, patent ownership and whether or not them have engineers or a presence on standards committee's. It's the standards that really catch my eye. Hopefully, if they conform, than I have positioned myself and the institution for the future. If not, then the trouble begins. Needless to say, we chose Alcatel/Aruba. They conform to standards. So far, we have rolled out WifiVOIP, Multicast (video/audio), wifi VPN, seamless roaming. It all works. I read the article regarding Network Computing analysis of CISCO vs. Meru. Honestly, they did a very thorough job. What I got out of the article was that indeed Meru was/is tweaking the 802.11 duration value. To me, this is a red flag. This means they are not conforming to standards. Has Meru responded to Network World or their customers? Seems to me if this wasn't true, there would be lawsuits or at least a rebuttal. Here's one of the engineers e-mail address, [EMAIL PROTECTED] I would contact him and ask the question. Anyway, let's get back to testing or piloting technology. By virtual cell vs traditional micro-cell WiFi I assume you are talking about having multiple access points advertise the same BSSID on the same channel. Virtual cell appears to clients as a single access point. In this definition virtual cell would result in more clients contending for the given channel within a larger coverage area.
Contention in WiFi is generally managed by CSMA/CA (collision avoidance). CA is used instead of CD (collision detection) because clients are sometimes not within range of other clients. You can create virtual-contention to go with the virtual-cells by tweaking access point timers to be shorter than client timers, but the single channel or access point bandwidth is fixed. You raise a very good question about the data/analysis since the number of vendors promoting such concepts is very limited. Place 3 micro-cell access points on 3 different channels in a coverage area. Associate 3 clients 1 per access point. Measure. Place 3 virtual-cell access points on same channel in same coverage area. Associate 3 clients. Measure. Be sure to take bi-directional measurements with simultaneous TX/RX to experience the half-duplex nature of WiFi radio. I am confident you will push more packets over 3 channels than 1. Be sure to power-off the system you are not testing. Shorting timers or counters by one system can adversely impact other client and access point devices even with only background traffic. There is 3rd party vendor/bake-off documenting the results but you have indicated that you do not consider it. All the best Russ Leathe Director of Networking Gordon College Wenham, MA ~ Russ ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
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