802.11ac is the fifth generation protocol of Wifi family. 802.11ac is subdivided into two waves, Wave 1 (available now) and Wave 2 (available by the end of 2015). The first wave of 802.11ac can deliver up to 433 Mbps (low end), 867 Mbps (mid-tier), or 1300 Mbps (high end) at the physical layer. The second wave of 802.11ac can provide up to 3.47 Gbps.
Note: SonicPoint appliances ACi/ACe are Wave 1 products. SonicWave products are Wave 2.
Madatory: TX and RX of A-MPDU Optional: RX A-MPDU of A-MSDU
Multi-User MIMO (MU-MIMO) to enable transmission of more streams to several users simultaneously. New feature allows an AP to transmit different streams to several targeted clients simultaneously.
Beamforming (Sounding): this feature enables the beamformer to precisely steer its transmitted energy and path toward the receiver.
Note: Wave 1 solves most problems today, it is capable to achieve the speeds of TCP to most single 3 stream and signle stream (smartphone) clients. For Wave 1 of 802.11ac, you don't have to upgrade your current network. While, with future Wave 2 speeds (more than 2 Gbps), the uplink will require upgrading to use multiple GigE ports or even 10GigE ports.