Cisco Cisco Aironet 1600i Access Point 기술 참조

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Cisco Aironet Series 1600/2600/3600 Access Point Deployment Guide, Release 7.5
  Understanding 802.11ac and the option module
Figure 71
Current channel allocation plan ETSI Theater.
What’s in the future as far as spectrum allocation?
In the US there are currently 22/10/5/1 channels with bandwidth 20/40/80/160MHz channels
With opening up of 5.35-5.47GHz & 5.85-5.925GHz, the number of channels increases to 34/16/8/3
If the industry manages to take back the TDWR channels, the number of increases to 37/18/9/4
So as time progresses we should see additional channels becoming available.
Client Band Steering
In order to optimize client performance, 802.11ac clients are able to take advantage of ECBF – Explicit 
Compressed Beam-Forming a IEEE 802.11ac standardized method of Beam-forming (similar in some 
ways to Cisco’s Client Link) but slightly different as the .11ac client needs to send “sounding 
information” to the AP and then the AP uses that sounding information (from the client) to best send the 
signal back to the client using (beam-forming).
Note
ECBF only works with 802.11ac clients, Cisco Client Link continues to be used with non-802.11ac 
clients to improve the overall performance of 802.11n and legacy clients resulting in an improved 
performance with all clients rather than just 802.11ac clients.  This helps maintain solid connections to 
the AP without having to bounce clients off of the AP using other methods such as signal strength 
causing needless roaming with the client is not actually engaged in passing traffic.
Note if is it a significant advantage to allow the module to service the 802.11ac clients while the 
integrated radio services the non-802.11ac clients.  Should the 802.11ac client require something the 
module radio does not support (for example, Cisco Client Extensions “CCX elements” the 802.11ac 
module will push the client to the integrated radio to service that request.
802.11ac Client Recommendations
At the time of this writing, 802.11ac clients are just now starting to get integrated into smart phones. 
Devices like Samsung’s Galaxy S4, ZTE’s Grand Memo and the HTC One phone are early to market 
802.11ac devices. It is expected that integrated notebooks and tablets (those devices often supporting 2 
and 3 spatial streams) will start to emerge later in the calendar year.