Hi Kevin,
I was wondering if you did any tests with a non-Meru AP in the same physical space downloading with the Meru APs? Mainly, I'm interested in seeing if there is a marked performance drop-off. I suspect that the efficiencies in the Meru networks are gained at the expense of system robustness, but it would be very interesting to have an empirical test of this.
--Sascha
Date: Tue, 5 Apr 2005 11:25:13 -0400 From: Kevin Miller <[EMAIL PROTECTED]> Subject: Re: MERU networks questions
To followup on some of these conversations.. I've been looking at the Meru technology a bit in the past few months, intrigued by the single channel claims. I recently ran a density test with the 'virtual AP' (two APs on a single channel) to test the performance. We had 30 clients (mix of b/g) in a room downloading a 10mb+ file simultaneously.
In followup to this test, I've had a chance to talk with Meru's CTO and discuss their technology. Based upon my experience and conversations, I hope to clarify some points that have been raised here.
The fundamental Meru technology is their ability to effectively manage co-channel interference. They do this with the virtual-AP concept; APs present the same BSSID so clients "see" a single AP where there are, in fact, multiple radios in space. They believe the technology coordinates APs utilizing the same channel well, reducing contention for the same space.
The reason they see for needing to do this is based upon trying to deploy APs for 802.11g coverage. If you're trying to get 36Mbps coverage, the number of APs you need means that your 802.11b clients will see many radios on the same channel, and will thus be causing interference when they transmit.
In our density test, we placed two APs on a two channels and tested the performance -- it was quite good, as we'd expect. We then tested two APs on a single channel, and found the performance was much less.
In discussing these results with Meru, it was confirmed that in planning for density, the use of multiple channels is suggested. There's no magic here -- with two APs in close proximity on a single channel, the performance is expected to be approximately half that of two APs on two channels. However, the system continues to manage co-channel interference between APs on common channels.
So I wanted to provide some insight on that.. if there are other questions, feel free to ask on or off list..
-Kevin
-- Kevin C. Miller Network Architect Office of Information Technology Duke University
-- Sascha Meinrath President * Project Coordinator * Policy Analyst Acorn Worker Collective *** CU Wireless Network *** Free Press www.acorncollective.com * www.cuwireless.net * www.freepress.net
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