&gt; Isn&#x27;t fragment reassembly essentially implying all the packets (fragments) will arrive, and will be rearranged in order? i.e. exactly what TCP does?<p>No. It is implying that it does what UDP does. TCP is different because it constructs a continuous stream. UDP is inherently packet&#x2F;message based.<p>UDP ensures that all of the IP fragments for a given UDP packet get reassembled and rearranged and order. The UDP packets themselves are not arranged in order, and it is possible to see duplicates.<p>&gt; For example imagine sending a single 1MB packet via UDP<p>Not possible. You can&#x27;t send more than a 65,507 byte packet via UDP[1].<p>Sigh... unfortunately, there are a lot of misconceptions about the basic plumbing of TCP&#x2F;IP.<p>[1] <i>UPDATE</i>: as was pointed out in comments, my statement was only true for IPv4. Since IP packets in IPv6 can have jumbograms larger than 65,535 packets, IPv6 UDP does support larger packets. Of course, in that case, UDP doesn&#x27;t handle the fragmentation&#x2F;defragmentation protocol itself, and of course GCE won&#x27;t handle anything IPv6.