Configure Pim-Sm; Important Points To Remember; Related Configuration Tasks - Dell Force10 S4810P Configuration Manual

High-density, 1ru 48-port 10gbe switch

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source, including the RP, create an (S,G) entry and list the interface on which the message was

received as an outgoing interface, thus recreating a SPT to the source.

3. Once the RP starts receiving multicast traffic via the (S,G) it unicasts a Register-Stop message to the

first-hop DR so that multicast packets are no longer encapsulated in PIM Register packets and unicast.

Upon receiving the first multicast packet from a particular source, the last-hop DR sends a PIM Join

message to the source to create an SPT to it.

4. There are two paths, then, between the receiver and the source, a direct SPT and an RPT. One router

will receive a multicast packet on two interfaces from the same source in this case; this router prunes

the shared tree by sending a PIM Prune message to the RP that tells all routers between the source and

the RP to remove the outgoing interface from the (*,G) entry, and tells the RP to prune its SPT to the

source with a Prune message.

FTOS Behavior: When the router creates an SPT to the source, there are then two paths between the receiver

and the source, the SPT and the RPT. Until the router can prune itself from the RPT, the receiver receives

duplicate multicast packets which may cause disruption. Therefore, the router must prune itself from the RPT as

soon as possible. FTOS optimizes the shared to shortest-path 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.

If a loopback interface with a /32 mask is used as the RP, you must enable PIM Sparse-mode on the

Configure PIM-SM

Configuring PIM-SM is a two-step process:

1. Enable multicast routing using the command

2. Select a Rendezvous Point.

3. Enable PIM-SM on an interface. See page 780.

Configurable S,G Expiry Timers on page 781

Configure a Static Rendezvous Point on page 782

Configure a Designated Router on page 783

Create Multicast Boundaries and Domains on page 784

PIM-SM Graceful Restart on page 784

Monitoring PIM on page 785

from CONFIGURATION mode.

ip multicast-routing

PIM Sparse-Mode (PIM-SM) | 779