How does UDP decide the maximum size of a UDP datagram?

What will be an ideal response?

For PMTUD, traceroute can be used on UDP sending packets with the ``dont"

fragment bit set. The size of the first packet is the MTU of the outgoing interface, and

whenever an ICMP ``cant" fragment& error is received; the size of the packet is reduced. If the router sending the ICMP error sends the newer version that includes the MTU of the outgoing interface, this value is used for the next datagram size; otherwise next smallest MTU is used. There are a limited number of MTUs, so a table of the likely values can be used for the next

smallest value referred to RFC 1191 [Mogul and Deering 1990].