Introduction – HP 3500YL User Manual
Page 108
PIM-SM (Sparse Mode)
Introduction
Introduction
Feature
Default
CLI
Enable PIM-SM Support
Disabled
Configure PIM-SM on VLAN
Interfaces
Disabled
Configure Router PIM Context
Bootstrap Router Candidate
Rendezvous-Point Candidate
Notification Traps
Shortest-Path Tree
Disabled
Display Multicast Route Data
n/a
Display PIM-Specific Data
n/a
Display PIM Neighbor Data
n/a
Display BSR and C-RP Data
n/a
Display Current RP-Set
n/a
Display Candidate-RP Data
n/a
In a network where IP multicast traffic is transmitted for multimedia applica
tions, such traffic is blocked at routed interface (VLAN) boundaries unless a
multicast routing protocol is running. Protocol Independent Multicast (PIM)
is a family of routing protocols that form multicast trees to forward traffic
from multicast sources to subnets that have used a protocol such as IGMP to
request the traffic. PIM relies on the unicast routing tables created by any of
several unicast routing protocols to identify the path back to a multicast
source (reverse path forwarding, or RPF). With this information, PIM sets up
the distribution tree for the multicast traffic. The PIM-DM and PIM-SM proto
cols on the switches covered by this manual enable and control multicast
traffic routing.
IGMP provides the multicast traffic link between a host and a multicast router
running PIM-SM. Both PIM-SM and IGMP must be enabled on VLANs whose
member ports have directly connected hosts with a valid need to join multicast
groups.
PIM-DM (described in chapter 3) is used in networks where, at any given time,
multicast group members exist in relatively large numbers and are present in
most subnets. However, using PIM-DM in networks where multicast sources
4-4