ESP8266 Community Forum

I have an application specific question which may not make much sense in the "real world". Can an ESP8266-01 send a UDP packet to itself? Or, in other words, can it simultaneously send and receive UDP packets reliably?

I have several switches which are all mapped using UDP packets. Some ESPs act as pushbutton switches and others act as receivers controlling relays.

In circumstances where a relay and a switch need to be in the same location, I could (and have been) easily control the relay with a simple if... digitalWrite.... type statement in a traditional way (ignoring any UDP communication). However, to hold true to my mapping scheme, I would like to have the ESP send a UDP packet (as it would for any "remote" device), but rather than sending it to a second ESP-01, I want it to essentially send it to itself.

This would mean the pushbutton (send a packet) is blind to the fact that the relay (receive a packet) is on the same board, or across the WLAN. Everything gets treated the same way.

UDP is working fine for me. I understand how to send and receive packets. I just wonder if an ESP can send a packet to itself. It would look like it is sending a packet to its own IP address.

Is this within the ESP-01 ability? UDP protocol? And, will it be reliable?

Thanks for the input. I realize how impracticle this approach must seem.

as WiFi is not duplex, devices tend to mute rx during sending, so --> mostlikely NO
(but that is not specific to esp8266)

but you can easily test it yourself and report your findings for the benefit of others ...

I think I read (long ago) that it would get the packet. But it was an internal thing and done before the radio. So while I agree that the radio prevents itself from hearing the actual transmission it still would be worth trying to see if it would work.

As we speculated. It does not seem possible for an ESP to send and receive UDP at the same time.