Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual page 428

Understanding How PIM Snooping Works
Figure 28-1
switches flood the PIM join message intended for Router B to all connected routers.
Figure 28-1
\
Receiver
IGMP join
Figure 28-2
switches restrict the PIM join message and forward it only to the router that needs to receive it (Router
B).
Figure 28-2
Receiver
IGMP join
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
28-2
shows the flow of a PIM join message without PIM snooping enabled. In the figure, the
PIM Join Message Flow without PIM Snooping
Router C
SP network
(*, G) PIM join
Router A
shows the flow of a PIM join message with PIM snooping enabled. In the figure, the
PIM Join Message Flow with PIM Snooping
Router C
SP network
(*, G) PIM join
Router A
Chapter 28 Configuring PIM Snooping
Router D
Router B
RP Source
Router D
Router B
RP Source
OL-11439-03