Does anybody know how can I set the link loss for multicast? I set it for unicast, and it worked. However, when I set it to one of links in multicast, there were no packet loss. I wrote the codes as follows: set lossylink_ [$ns link $n(1) $n(0)] set em [new ErrorModule Fid] set errmodel [new ErrorModel] $errmodel unit pkt $lossylink_ errormodule $em I appreciate any comments. Jaehee