I have a server on a server farm L3 switch, that's going to send images to workstations that are connected to various access switches on different VLAN's. I need to set up multicasting, so either a host sends a request to this server to start a session, or the server will send a request to a number of hosts. I've read the multicasting docs on a Cisco website, but I feel really lost on how to set this up between the Server Farm switch that houses the server, the Core L3 switch that routes all the VLANs and the access L2 switches where the hosts are connected.
You will need to remove the following command from your configuration:
ip pim spt-threshold infinity
This command, with the keyword infinitiy, prevents a router from ever switching to SPT.