unkown protocol start from 000xxxxxxxxxxxxxxx0510101217203406

Hello i have device and want to know what is the protocol ?
The device request to my server using UDP and the device send data like this
000xxxxxxxxxxxxxxx0510101217203406600000000000000000000000000000000029400020cc00000000005e
the xxx is IMEI 15 digits, it us always send every request.

I had some research with 3 different devices after the IMEI, always send 0510101217203406, but i don't know the protocol is
I had search on list protocols documents and try to match on example protocols.

But i have no idea what protocol it is, anyone can help ?

It's a binary protocol, so we would need protocol documentation.