Silence on the Wire

Beyond Internet Protocol

One consequence of many of the design decisions made when devising IPv4 is the lack of a reasonable reliability guarantee, even if the network itself is behaving reliably. Although IP ID numbers are intended to minimize the risk of reassembly collisions, their relatively small 16-bit size (which allows for 65,536 possible values) permits problems to arise occasionally when two packets with identical IP IDs are reassembled at the same time. Also, IP header checksums are simply insufficient to provide reliable integrity protection; although unlikely, a random change in a packet could still give an identical checksum. Too, if the network actually failed, there is no way to find out what data has gone missing, even if the ...