Implementing multicast stub routing between the stub and distribution device in PIM sparse mode (PIM-SM) environment eliminates
the need to maintain the group-to-Rendezvous Point (RP) mapping cache on the stub device, and saves periodic update bandwidth--if
Auto-RP or PIM bootstrap router (BSR) is used for distributing the RP information.
Multicast stub routing is intended to forward multicast traffic from the distribution device to the stub device. It is possible
to have sources directly connected to the stub network, and, receivers must be directly connected to the stub device and cannot
be further downstream.