Hello I'm new user of ns i 'm trying to simulate a network where only some of nodes reconize the multicast I've tried $ns mrtproto DM $node1 $node2 ... but it does'nt work I used [liste $node.....] does'nt work what should I do?? what's wrong? thanks Ibtissam PS: I've tried to find where mrproto is defined but without succes