PIM consists of two modes: dense mode and sparse mode. What are the differences between these two modes? Why define two modes? When a host sends a packet to a multicast group, how is the packet...

PIM consists of two modes: dense mode and sparse mode. What are the differences between these two modes? Why define two modes?

When a host sends a packet to a multicast group, how is the packet handled differently by the designated router under DVMRP and PIM-SM?