RFC 9869: Datagram Packetization Layer Path MTU Discovery (DPLPMTUD) for UDP Options

This document specifies how a UDP Options sender implements Datagram Packetization Layer Path MTU Discovery (DPLPMTUD) as a robust method for Path MTU Discovery (PMTUD). This method uses the UDP Options packetization layer. It allows an application to discover the largest size of datagram that can be sent across a network path. It also provides a way to allow the application to periodically verify the current Maximum Packet Size (MPS) supported by a path and to update this when required.