The mesh isn't doing MQTT or TCP. They're using MQTT to bridge between meshes, with mesh nodes that have an internet connection or are paired to a smartphone with an internet connection relaying mesh traffic with an MQTT server.

MQTT is used for map reporting, and sometimes as a "fallback" or to connect distant meshes.

Also very good way to instantly spend all your air time. Remember, legally you can only transmit at something like 10% of time. In some bands even less, afaik.

> Remember, legally you can only transmit at something like 10% of time

In Europe. See the duty cycle limits summarized at https://meshtastic.org/docs/configuration/radio/lora/#region

It's best not to retransmit MQTT. Unless you want to set up some very specific link between two meshes, or just some private or non-default channel.