When adding a per-segment checksum to a segment, TCP and UDP all include some fields in the IP layer before the segment has been passed to its underlying layer, the IP layer. How could TCP and UDP...

When adding a per-segment checksum to a segment, TCP and UDP all include some fields in the IP layer before the segment has been passed to its underlying layer, the IP layer. How could TCP and UDP know the values in the IP header?

The text goes into some detail introducing the different versions of TCP. Find three more TCP versions. Itemize them and highlight their contributions within three lines of words for each TCP version.