[ns] unicast in session multicast

[Sencun Zhu <szhu1@ise.gmu.edu>]

Hello,all:  

     I want to use session multicast for scalablity purpose. besides the
multicast communication, I have to have some unicasting, like: a member
requests the multicast group address from the manager, then joins. I
wonder if there is any way to achieve this. I wonder it is wrong way
to  have a sessionhelper for every member in this case. If I do nothing
else(just like Dense Mode or Centrilized Mode), then I got core dump,
since the target_ of a member's agent is 0x0 .


thank you


Sencun