Controller Based WLANs

Q:

What are the realistic expectations for IEEE 802.11 standard wireless throughput?

Maximum Throughput

Maximum throughput varies based on signal strength, RF noise, packet size, encryption, and other factors.  The theoretical throughput listed for each protocol is usually not possible. A typical, good connection would yield a little less than half the theoretical maximum for the protocol.

For example, the theoretical maximum for 802.11g is 54 Mbps but a typical, very good connection might operate at about 24 Mbps.

Wireless Connections

Wireless connections are shared by all of the users connected to that radio.  A user will take his or her share of the bandwidth, plus some overhead involved in managing each.  

         Depending on the protocol, 15 to 30 users is about the maximum number for any one radio.

5 Ghz Protocols

5 GHz protocols, such as IEEE 802.11a and 802.11n, will lose signal intensity more quickly than 2.4 GHz frequencies (b, g, and n).  The higher frequency is more susceptible to obstruction and distance.

Shared Bandwidth

Sharing the bandwidth with a slower protocol will slow performance.  In other words, if an SSID allows both 802.11b and g, the presence of only one b user will drop the bandwidth of all users to 802.11b rates.  

        802.11n will operate more slowly if it has to run in compatibility mode with 802.11 a or g.