9, under what circumstances will the datagram method of packet delivery prove useful.
See here I had mentioned in the lecture that datagram method will be faster in general.
But you can try to figure out what kind of applications may gain by using datagrams.
Because one thing is true I had mentioned datagrams do not guarantee delivery at the
destination. There can be some packets which are not received. Some out of order
delivery, so some applications which would not mind if this kind of things happened.