Most 802.11n enabled Access Points out there advertise themselves as follow: 2x3:2, 2x2:2. Ever wonder what these numbers mean? Well here is what I make out from them: You will find 802.11n with the following flavors: 1x1:1 1x2:2 2x2:2 2x3:2 3x3:2 Where: TxR:S T - Transmit R - Receive S - Spatial The spatial is your "money". Each spatial equates to 150mb, so you will see 3x3:3 equates to 450 mb.Thats why with Cisco APs and others, you will only ever get 300 with xXx:2. Let me add further, 2 on the transmit means you will use no more than 2 antennas to TX on. 3 on the receive means you will use 3 antennas to rx on. The spatial is your streams. if you have a 2 stream AP, that means its the most number of streams network will have, that too if your environment is favourable to use 2 streams, just because it can do 2, doesn't mean it will always do 2. 802.11n although by standard could support 600 4x4:4, its VERY unlikely we will see that in the enterprise. Atheros
Cisco Switch and Router Configuration