Yep. Very few people (less than 5%) who deploy dense wireless LANs understand that the interference radius around each access point omni antenna is 4 times to 8 times (or more) GREATER than the usable communications radius. People end up putting too many access points too close together resulting in a huge DECREASE in aggregate throughput and REDUCED network reliability. These symptoms will only emerge once traffic levels build up and wireless frames are colliding with each other all over the place. Then the network manager starts adding access points and makes the problem worse.
On top of that, most wireless LAN vendors push the idea that throughput and reliability problems will be SOLVED by adding more access points. The wireless LAN vendors also tell the customer that their "smart" controller will help reduce the self-interference between the access points by "intelligently" managing access point power and channel. Those of you who don't live in a major city will have to use your imagination to follow this example but this vendor argument is like saying that placing a traffic cop with a whistle in the middle of a freeway that is moving at 2 miles per hour will help to "manage" the flow of traffic and speed the traffic up; it won't. The cop will only manage to distract the drivers and slow the traffic down even more. So if you are deploying a wireless LAN that needs a lot of access points to handle a many simultaneous users and high levels of user traffic and different types of user traffic (like voice and data), what should you do to get your WLAN to work and to meet management and end-user expectations? Let's hear a few opinions from people about how to get good WLAN performance. BTW, these very same principles apply outdoors in WISP deployments. After we hear from five or six people, I'll offer my solutions (if you all don't beat me to it). ;-) Oh yeah, one more thing... PLEASE post your solutions over on the the WISPA Members list. This is the kind of info that I feel paying WISPA members deserve to have access to. In my view (I know this is "old-school" thinking these days but remember, I'm old), there really is no such thing as a "free lunch". Those folks who support WISPA deserve to receive information that is a cut above the "free information" (and dis-information and advertising hype) that has distorted people's sense of reality these days. Your normally quiet and humble servant, jack CHUCK PROFITO wrote: > WLAN stress test uncovers 802.11 performance problems > The tests confirm two troubling issues for high-density nets > > Everyone on this list probably already knows this, especially if you have > read Jack's book, but John Cox from Network World did a good job explaining > it. Usage vs. self interference and scaling up the access points. > Interesting, where they had the antennas folded flat, it worked better, but > they don't know why...he forgot it became an unintentional sector. I bet if > you put in Alvarion with packet and VoIP priority it would blow this test > out of the water. Maybe? What do you folks think? > > http://www.arnnet.com.au/index.php/id;1526372596;pp;1 > Or http://tinyurl.com/2cebwk > > Chuck Profito > 209-988-7388 > CV-ACCESS, INC > [EMAIL PROTECTED] > Providing High Speed Broadband > to Rural Central California > > > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ > > > > -- Jack Unger - President, Ask-Wi.Com, Inc. Serving the Broadband Wireless Industry Since 1993 FCC License # PG-12-25133 Author of the Cisco Press Book - "Deploying License-Free Wireless WANs" Vendor-Neutral Wireless Training-Troubleshooting-Consulting Phone 818-227-4220 Email <[EMAIL PROTECTED]> -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
