Pim sparse mode – Multicast is used to send the data to the multiple receivers at the same time. Multicast reduces the load on the servers (Senders/Source in multicast term), provides efficient capacity usage on the network links.
Efficient data transfer, optimised resource usage , simplified configuration, optimum bandwidth usage are the main characteristics of Multicast.
In the diagram below; unicast and multicast flows are shown.
From the source, if same packet will be sent , with unicast transport you send two copies. Read more