How many laptops to a wireless AP?

[Alan Johnson]

On Sat, Feb 28, 2009 at 11:14 AM, Stephen Ryan <stephen at sryanfamily.info>wrote:

> I think this is the answer right here; wireless uses the same CSMA/CD
> algorithm that Ethernet does, so using WiFi is just like using the old
> unswitched hubs.  Documents from a few years back talking about
> unswitched hubs reference a 30-40% limit on utilization; collisions end
> up limiting maximum performance to no more than that.


For 802.11b, the problem is some what worse than the old wired hub, but
11a/g uses a slightly smarter algorithm that dramatically reduces the
windows of opportunity for collisions.  The AP acts like a bad traffic cop
and yells "clear to send" to ever one at once, at which point there is a
chance for collision.  If there is a collision, some one is picked as the
winner and gets the next few time slices.  After a bit, there is another
free-for-all, and another winner is picked.  This happens hundreds of times
per second and is some times adjustable in the advanced wireless settings,
but you probably never need to mess with it.

-- 
Alan Johnson
alan at datdec.com
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