Alcatel Carrier Internetworking Solutions 6648 - Manual (Page 287)

Troubleshooting PIM-SM Source-Based Tree
OmniSwitch Troubleshooting Guide September 2005 page 16-25
Source-Based Tree
PIM SM protocol allows a DR to build a Shortest Path Tree, which could provide a shortest path toward
the source. It is being referenced as Source Based Tree because the DR closest to the receiver is initiating
the process.
When a PIM SM graft the shared path tree, a counter is initiated for this specific group on the last DR
closest to the receiver that will be incremented every data packet received. Once the data exceeds a config-
ured threshold the router switches over to source based tree mode. A JOIN message is sent directly toward
the source, after the shortest path tree is activated the DR sends a PRUNE message to the RP.
Note. Currently, the threshold cannot be configured from Clips.
MCAST SOURCE
225.1.1.1
MCAST RECEIVER
for 225.1.1.1
JOIN
225.1.1.1
PRUNE
225.1.1.1
DR