[ns] reset multicast address

[Jianliang Zheng]

Hi, all!

I have a problem as how to reset the multicast address.

I need to reset my multicast address after sending out a message, so that I can 
multicast to a different group next time. I used 'joint-group' and 'leave-group' 
to do this. The problem is that I cannot execute 'leave-group' immediately after 
sending the message. I have to wait until the message has been sent to all the  
agents in the group. To do this, I have to know how long I should wait and also, 
I need to save the multicast list. Is there any easy way to do this?

Your help will be highly appreciated.


Regards,

-Zheng