My cisco 4506 goes nuts every time i turn multicast on. Unfortunately most of my inherited network is on vlan 1, which i'm slowly segmenting. When ever we need to use a multicast application i have to turn multicast on for vlan 1 (ip pim sparse-mode) When i enable it my cpu stays around 80-100%. When i run a show ip mroute counters there are about 50 routes in it. I guess my question is what can i do about this. I'm sure there are a few different applications that use it but there are all kinds of MC IP's. If i ping one of the IP's, it replays back from a network printer, a proximity panel. is this even reliable?