I don't really know exactly what you're driving at here, except maybe that NET::FTP and LWP both allow you to make FTP requests, but not with the same underlying code. It seems pretty obvious to me. When you're using LWP, your FTP request is usually made through a HTTP::Request which fits the design for how to use the module consistently across several services.
As far as a "command TCP/IP" library, I must confess to not having any idea what you're talking about. Do you want a library where we can
$tcpPacket->setSYNFlag();, or are you talking something a little more high level?
GuildensternNegaterd character class uber alles!