Matter supports large quantities of device OTAU in a more secure way. Matter leverages the IP transport layer to do a 1-to-1 transfer of OTA images fragmented in large packet transfers. Thread network will route the IP traffic in the most optimal way to the correct device, not disturbing the rest of the network.
MATTER uses either Transmission Control Protocol (TCP) or Matter’s Message Reliability Protocol (MRP) over User Datagram Protocol (UDP). MRP allows sender to provide an automatic retransmission mechanism and receiver to acknowledge for reliable messages, and duplicate message detection. The underlying Thread protocol in his turn ensures reliable transfer of the UDP messaging.