In the following diagram, assume that the receivers are joining a stream using 239.1.1.1 as multicast address from the source connected to R1:
In our example, 10.1.8.8 is acting as the RP, and this RP is connected to R2:
- Receivers will send an IGMP join request for 239.1.1.1 to the connected multicast routers. The LHR routers (R3 and R4), upon receiving the IGMP joins from the receivers, will build a shared tree towards the RP. In our example, R3 and R4 will use R2 as an upstream router to build the tree towards RP.
- The FHR connected to source, upon receiving the first multicast traffic, will encapsulate it with a PIM register ...