UDP Broadcast Performance is Worse in AP mode than STA Mode

[fairfax]

We have a relatively simple ESP32 application ESP-IDF (FreeRTOS) that converts Serial Data in to TCP or UDP Packets. By default we are using the ESP32 in AP mode but also allow the user to select STA mode.

A TCP connection works perfectly in AP and STA mode but we have found that there are a large number of UDP packets that are not transmitted in AP mode (25%) and a limited number perhaps 1-2% not transmitted in STA mode.

We have just one Mac connected to the ESP32 in AP Mode, we are using a Baud rate of 38400 and we are sending a burst of messages each with a counter and then a UDP client program, running on the Mac, uses the counter number to record which packets are not transmitted. We have also confirmed that the packets are not getting out by running Wireshark on the Mac.

We are using the SDK configuration settings that you used for the IPerf Example in which you recorded 30Mbit UDP throughput, which would be great if we can ensure all packets are transmitted.

We are using a UDP broadcast address of 255.255.255.255

Do you have any suggestion as to why this is happening and if there is anything that we can do to improve performance?

Thank you in advance for any advice you can give us.

[michprev]

I am experiencing similar issue viewtopic.php?f=2&t=9322. I have not solved it yet but it seems that ESP always sends all data but they are blocked / dropped / whatever by system. You should try to connect more listening devices at the same time.