Users Guide

IPv4 and IPv6 Multicast 1533
Figure 44-3. PIM-SM Sender Registration—Part 2
• As soon as the SPT is built from the Source router to the RP, multicast
traffic begins to flow unencapsulated from source S to the RP.
• Once this is complete, the RP Router will send a “Register Stop” message
to the first-hop router to tell it to stop sending the encapsulated data to
the RP.