Basic WiFi communication

[Dumbledore]

Morning!

First of all, I just started programming dev boards for the first time today, so please excuse my clumsiness.

I got two ESP boards and connected them over WiFi (one AP, one station). I'm now trying to figure out how they're able to communicate with each other. So for starters, I've tried to create an empty frame and send it from the station to the AP, using the respective MAC addresses and esp_wifi_80211_tx.

Some basic questions:
1) What's the absolute minimum layout of an "empty" frame? (Like frame control, duration, addresses...)
2) How can I check if the frame reached the AP? From the API, I only found esp_wifi_set_promiscuous_rx_cb as a way to register a callback function when receiving a packet, but I'm not using promiscuous mode since the whole WiFi network just has those two members anyway and no other communication will take place.
3) Will the ACK packet be returned automatically? Will those trigger the esp_wifi_set_promiscuous_rx_cb (or whatever else I'm going to use) callback function too?

Thanks in advance!

[WiFive]

Have you tried esp-now?
https://docs.espressif.com/projects/esp ... p_now.html

[Dumbledore]

Well, my ultimate goal is to simply get the CSI (wifi_csi_info_t) from the WiFi ACK packet. From what I've read, esp-now isn't utilizing those, right?