H3C S5500-EI Series Operation Manual page 118

Operation Manual – Multicast
H3C S5500-EI Series Ethernet Switches
Figure 7-4 BSR and C-RPs
IV. RPT establishment
Figure 7-5 RPT establishment in a PIM-SM domain
As shown in
1) When a receiver joins a multicast group G, it uses an IGMP message to inform the
directly connected DR.
2) Upon getting the receiver information, the DR sends a join message, which is hop
by hop forwarded to the RP corresponding to the multicast group.
3) The routers along the path from the DR to the RP form an RPT branch. Each
router on this branch generates a (*, G) entry in its forwarding table. The * means
any multicast source. The RP is the root, while the DRs are the leaves, of the RPT.
Figure 7-5, the process of building an RPT is as follows:
7-9
Chapter 7 PIM Configuration