Unicast RPF path

[Shuqian Yan <syan@jupiter.nal.utoronto.ca>]

Hello, all

This is a question about unicast RPF model used in ns2.

If I have the following partial topology,

1-----2-----3------4------5

numbers are representing nodes and the links between nodes are duplex
links.

if some agent in node 1 unicast a pkt to the final destination,
which is node 5. since I also want the pkt to be received by the 
intermediate node, in my algorithm, I always use rpf-nbr to find 
the next hop where the agent will be connected, the pkt is thus
forwarded hop-by-hop based on RPF until finally reached node 5. 
The overall path in this case is 1->2->3->4->5.

suppose node 5 unicast a pkt toward finaldst node 1, and again I want
the pkt to be received at intermediate nodes, so I also use the rpf-nbr to
find the next hop towards node 1. My question is: is the path for node 5
unicast pkt hop-by-hop towards node 1 will be the reverse path of node 1
unicast pkt hop-by-hop towards node 5, or is the path will be
5->4->3->2->1?  could the path be different for the two cases I described
above?

thank you,

shuqian