I've heard the phrase "aggregated throughput", but it's very confusing to me. Could someone explain this a little better for me?
I've read that, for example, if you place two (2) 802.11b APs in close proximity, you'll effectively double the available bandwidth to 22Mbps. If you place three (3) APs together, you'll effectively get 33Mbps bandwidth, and so forth. Is this true?
Also, if you place multiple APs in close proximity to each other, you'll have to place them on seperate channels so the channels themselves don't interfere with each other, wouldn't you?
Your talking about several different things. First, lets tackle bandwidth and throughput. The advertised data rates of an access point is the "bandwidth" For example, an 802.11b access point provides data rates of 11, 5.5, 2 and 1 Mbps. This is not throughput.
If an AP provides a data rate of 11 mpbs, that is the bandwidth. The medium contention method of CSMA/CA puts about 50% or greater overhead on the wireless medium. Therefore, an access point with 11 Mbps bandwidth would actually only have "throughput" of 5.8 Mpbs or probably less. This thoughput is know as "aggregated throughput" because the wireless medium is a shared medium.
In other words, If you have an access point that provides 11 Mbps data coverage (bandwidth) and had six client stations associated to the access point, the total (aggregate) throughput of all six clients would be 5.8 Mpbs or less.
The other topic you are talking about is called co-location and yes the goal of co-location is to provide more "bandwidth" in one area.
O.K., great. Thank you, David.
The thing that's also confusing to me is: If you DO co-locate APs, you'd have to place them on different channels, wouldn't you? Otherwise they'll interfere with each other, wouldn't they?
Yes co-location requires you to use channels with frequency space that does not overlap. Therefore, you would use channels 1, 6 and 11 in the 2.4 GHz ISM band.
Another viewpoint on csma/ca :
Pardon the long url.