[Q] When is a src_ changeed...?

[Lee Kyeseon <kslee@ccl.chungnam.ac.kr>]

Hi, all

During developing using ns-II, I have many questions.
some of questions were solved, but  rests are vague.

So, I ask one question to you,
and I hope you could give me some advice.

Ex)
in ip.h, src()& dst() are exist.
I wonder when these are chaned.
as the following figure, at S src_ and dst_ of a packet are initiated,
and the packet is arrived at D through R1, R2.
when the packet is arrived at destination, src_ of that is same a
address of S?
or, whenever the packet is arrived at routers, src_ of that is changed
to address of R1/R2?

source ----------->router1----->router2----->destination
(S)                             (R1)               (R2)
(D)
src_ = addr of S
dst_ = addr of D

Thank you.