ESP-NOW performance is great

[gmag11]

Hello,

I'm developing a project based on ESP-NOW communication. It was difficult at first but now it is working flawlessly. I'm surprised on how this protocol performs.

https://github.com/gmag11/EnigmaIOT/

I understand that it uses "aloha" method to transmit. So collisions are expected to happen, but it is not what I'm observing. It is quite difficult to lose a message even if several communications are working in parallel.

My scenario is this. I have a gateway and 2 sensors (there will be many more in the future), all based on ESP8266.

1st sensor is sending messages every second to a gateway. Gateway is sending a binary file chunked on small parts (smaller than 250 bytes) to 2nd sensor node. This transfer has no flow control so it is sent at max speed that esp8266 hardware.

I get about 150 kbps in the transfer, but this can be limited by the fact that I'm software encrypting every packet before sending, so theoretically it could be faster. And very rarely I get a collision.

My question is: Is there any mechanism in ESP-NOW that tries to recover non confirmed packets due to collisions? I ask this because every time the 1st sensor transmits, second sensor stops receiving for an instant, but no messages are lost or corrupted.

Regards,
gmag11