tree switchover latency by copying and forwarding the first (S,G) packet received on the SPT to the PIM
task immediately upon arrival. The arrival of the (S,G) packet confirms for PIM that the SPT is created, and
that it can prune itself from the shared tree.
Important Point to Remember
If you use a Loopback interface with a /32 mask as the RP, you must enable PIM Sparse-mode on the
interface.
Configuring PIM-SM
Configuring PIM-SM is a three-step process.
1. Enable multicast routing (refer to the following step).
2. Select a rendezvous point.
3. Enable PIM-SM on an interface.
Enable multicast routing.
CONFIGURATION mode
ip multicast-routing
Related Configuration Tasks
The following are related PIM-SM configuration tasks.
• Configuring S,G Expiry Timers
• Configuring a Static Rendezvous Point
• Configuring a Designated Router
• Creating Multicast Boundaries and Domains
Enable PIM-SM
You must enable PIM-SM on each participating interface.
1. Enable multicast routing on the system.
CONFIGURATION mode
ip multicast-routing
2. Enable PIM-Sparse mode.
INTERFACE mode
ip pim sparse-mode
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PIM Sparse-Mode (PIM-SM)