How is really EspNow's ACK implemented?

[berguinsson]

Hey everyone.

I've done a small research about how to sending messages are implemented in ESPNOW protocol. I know that if the message is dropped off correctly at the receiver, then, an ACK is sent back and status==ESP_NOW_SEND_SUCCESS.

Despite that, i would like to know at low level how this ACK is implemented.
Is ACK sent like any ESPNOW message? How much time sender waits to receive ACK? Where is the status value assigned to be later compared if this is the same as ESP_NOW_SEND_SUCCESS or not?

i've read some information abaout MAC layer but i didn't understand very well, so if anyone could help me i would be so grateful.

Thanks for your help!

[WiFive]

Same as other 802.11 frame I think

[berguinsson]

Hello!
Well, nobody responsed on 802.11 post.
Do you know how ACK works? At least at Mac layer level.
Have a good day.

[WiFive]

https://warpproject.org/trac/wiki/802.1 ... nsmissions

[Mcccol]

I believe they're ACKed with a wifi CTS packet, which is clever, because those packets are tiny