PIM-SSM (Protocol Independent Multicast - Source Specific Multicast) is a variant of PIM-SM that focuses on improving the efficiency of routing multicast traffic from one specific source to many recipients. PIM-SSM simplifies the routing process and reduces latency by eliminating the need for centralized routing points (RPs) and routing trees. This protocol is ideal where high quality and low latency is needed, such as streaming video and IPTV.