Cisco Cisco Aironet 3700i Access Point 백서

 

 

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This has far more consequences at 5 GHz than at 2.4 GHz since 40 MHz channels are unlikely to be usable at 2.4 

GHz and 80 MHz channels cannot be used at 2.4 GHz. 

Last, but far from least, no two wireless networks are the same; every wireless network is different. Even parts of 

the same wireless network will be different. Thus, there really is no universal static configuration that offers 

optimization. The wireless network needs to adapt as conditions change. 

Interestingly, 802.11ac does include a feature called RTS/CTS with bandwidth indication that is intended to 

address dynamic channel width (read more about this in 

The problem is that this feature is rarely, if ever, used. So, given all the variables and complexity, how does one 

choose the best channel width? 

The answer is Cisco Dynamic Bandwidth Selection (DBS). 

DBS is a patent-pending enhancement and extension to Dynamic Channel Assignment (DCA). DCA selects the 

best channel number but has to be manually configured for 20, 40, or 80 MHz channel width. 

With DBS, the best channel number is still automatically assigned, but the DCA metrics are also used to select that 

best channel by accounting for all possible channels widths. The DCA algorithm compares 20-, 40-, and 80-MHz 

channel width options. The best channel width is automatically calculated using: 

1.  RF neighbor channel widths 

2.  BSS channel overlap ratio 

3.  Channel Utilization 

4.  Non-Wi-Fi noise 

5.  Wi-Fi interference 

6.  Number of client types and capabilities 

The result is a highly powerful mechanism for establishing a WLAN for optimal spectrum efficiency. In other words, 

a spectrum conservation plan is realized in which the necessary amount of spectrum is used based on the needs 

of the clients and the characteristics of the surrounding air. 

The tradeoff is basically operating at fastest over-the-air speeds (wider channels) compared to lowest latency (the 

least amount of wait time to get onto the air). Nevertheless, in both cases, performance is automatically optimized. 

Wider channels are used if the RF neighborhood is relatively free from congestion due to competing wireless 

networks. Narrower channels are used if the RF neighborhood is relatively dense. 

Network planning is also greatly simplified since heterogeneity of client devices is assumed from the beginning. 
Finally, all of this isn’t done only at network startup. This is about intelligently adapting channel width on a 

continuous basis. Why is this important? Very simply, DBS can help provide confidence in deploying 80-MHz 

channels.