Hi , I use the PIM-SM protocol implemented in NS-2.1b4 ,But i am not quite clear about the functionality of some points : -->How to make one RP for specific group? -->How to start the bootstrap mecanism in order to make RP points dynamically ? -->How to switch to the SPT tree? Many thanks for your help and time . Salam. ----------------------- Lazrak Mohamed email: [email protected] -----------------------