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Cisco AP 3700 PoE

mlinder01
Level 1
Level 1

Assuming we have a 802.3at (30W) capable Switch but we don’t need 802.11ac on the Cisco 3700 AP…can we disable the 802.11ac functionality ?

I also think that without disabling the 802.11ac functionality on the 3700 AP the AP/Switch will negotiate automatically on 802.3at (~20W) ? maybe i could set a max poe for 15.4W on the switch (Cisco 3650) so the AP can’t get more power... ?

Thanks for any informations!

Manuel

32 Replies 32

Leo where are you getting the information stating that the 3700 will operate at 3x3:2 when using 802.3af (15.4w)? I'm curious because the 3700 datasheet shows that 15.4 with no module it will operate at 3x3:3 a big difference in client performance. however i have several hooked up to 802.3AF power and 3 spatial stream AC clients are connecting at 2 spatial stream speeds.

 

thanks

eric

Leo where are you getting the information stating that the 3700 will operate at 3x3:2 when using 802.3af (15.4w)?

I am suspecting the information in the Data Sheet is incorrect.   

fredn
Cisco Employee
Cisco Employee

No need to disable .11ac functionality,

 

PoE power requirements

 AP-3700 (.3at) mode

 

Full functionality requires 15 Watts for the AP to shift into 4x4:3 mode with both radios enabled

With the WSSI module installed it is an additional 3W so draw is 18 Watts with both radios enabled.

 

In the described modes above, you cannot get to 15 Watts at the end of a CAT-5 cable using 802.3af (15.4W)

When using CAT-5e or better, there is about 1.4 Watt loss at the end of a 100m cable (for this reason)...

 

 For full functionality you should use either:

802.3at, PoE Plus, .3at injector, DC Power Brick, Cisco ePoE, or AIR-PWRINJ4

 

Also always use CAT-5e or better as there is more loss of power in Cat5

 If the additional power is not available and cannot be negotiated, the AP will function with reduced performance in 15.4 Watt (802.3af modes).

 

AP-3700 (.af) 15.4 Watt mode.

 

When in 802.3af mode the AP-3700 will come up in 3x3:3 mode with both radios (same as many competitors) who only have 3 radios but you lose the ability of that 4th radio which helps not only in overall performance but also allows the AP to beam-form (to a 3 spatial stream client).

 

Additionally, if you do need to use a module and still have a need to operate from a 15.4 Watt power source, the AP will still allow the three Watt module to run but will scale back to a 2x2:2 mode on the other two radios.

 

Regards,

Fred Niehaus N8CPI

Technical Marketing Engineer

Wireless Networking Group

Cisco Systems, Inc

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