Листовка для Cisco Aironet 2702i AIR-CAP2702I-E-K9

 

 

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Figure 4.    802.11ac Channelization (United States) 

 

In the United States, there are 20 to 25 20-MHz channels, 8 to 12 40-MHz channels, 4 to 6 80-MHz channels, and 

1 or 2 160-MHz channels. These numbers are ranges because of the evolving regulatory issues surrounding the 

different spectrum noted in 

. 

What if most clients at a deployment are still 802.11n clients with 40 MHz maximum? Does deploying 802.11ac 

APs mean fewer channels and more interference? As you would expect from an IEEE standard, the answer is a 
resounding “no.” It is entirely allowed for two 80-MHz 802.11ac APs to select the same 80-MHz channel bandwidth 

but for one AP to put its primary 20-MHz channel within the lower 40 MHz and the other AP to put its primary 20-

MHz channel within the upper 40 MHz. What this means is that 802.11n clients associated with the first AP can 

transmit 20 or 40 MHz as usual, at the same time that 802.11n clients associated with the second AP transmit 20 

or 40 MHz in parallel. What is new in 802.11ac is the ability for any 802.11ac client that sees the whole 80 MHz as 

available to invoke a very high-speed mode and to transmit across the whole 80 MHz. This is shown in 

.