Could anyone please explain me an idea of route cloning

[Putrycy <putrycydestengier%gmail.com@localhost>]

Hi people. Is there anyone willing and able to explain me (preferrably
simply) what is (and what is it for)
idea of route cloning ? As far as i know it's idea specific to BSDs. Im
doing some playing around in
network stack, but i can't get the point of some things, and your kind help
would help me and save a lot
of time i'd have to spend analyzing all network stack code.

Thanks in advance.
P.