Q about ip address and node id relationship

[Ghassan Chaddoud <Ghassan.Chaddoud@loria.fr>]

Hi all,
I have two Q.:
1)if I have a packet sent to a node n (i.e I have n_id), how to find the
ip address of n(i.e. how to obtain n's ip address from n id)? 

2) in Marc Greis's ping example, there is the code line(recv in
ping.cc):
hdrip->src_ >> Address::instance().NodeShift_[1]
what does this line do? and where to find a reference doc. about
NodeShift?

thanks in advance
-- 
Ghassan