Protocomm ble message bigger than MTU sizes

[xgroleau]

Hi, we are using protocomm over ble for our wifi provisionning but also for a custom endpoint that uses protobuf underneat.

Some of our messages can get up to 600 bytes, which is bigger than the maximum MTU size.

When sending to the device, we can split those in multiple writes, but when we want to send from the device, there is no way to do this, since protocomm_ble just sends it without chunking it.

Also, it seems we always need to send back data when handling a protocomm request. In our case if we split our data, we might not need to send data back when handling the first messages. But we get "Failed to allocate encrypt/decrypt buf len 0" when we don't return data.

Here are my questions:
Do we always need to return data for the ble implementation of potocomm?
How can I reply more bytes than the maximum MTU size?
How would you solve this problem (send packet bigger than MTU? We are going towards chunking with a header for now.


Thank you

[MicroController]

Just a thought: Protobufs are somewhat at odds with the basic concepts of BLE, where you have a set of attributes, each potentially with its own defined basic data type and value.