At 05:44 PM 9/24/2002 +0200, TOMSON ERIC wrote: >Last, while I definitely, clearly prefer calling Layer 2 data units >"FRAMES", I sometimes [over-]simplify the terminology of Layer 3 by making >the following distinction : "a datagram is the data unit before >fragmentation" ; "a packet is a piece of a fragmented datagram".
:^) A fragment of a datagram is itself a datagram; after you re-assemble them, the result is still a datagram. If the MTU was larger, you wouldn't have had to fragment it or reassemble, and the forwarding system still could have gotten it there without reference to a setup procedure (virtual circuit).