Pim-Ssm Overview - HP MSR1002-4 Configuration Manual

Figure 41 Relationship in view of multicast group address ranges
G
As shown in
admin-scoped zone 3 is a subset of the admin-scoped zone 1. The global-scoped zone
provides services for all the multicast groups that are not covered by the admin-scoped zones 1
and 2, G−G1−G2 in this case.

PIM-SSM overview

The ASM model includes PIM-DM and PIM-SM. The SSM model can be implemented by leveraging
part of the PIM-SM technique. It is also called "PIM-SSM."
The SSM model provides a solution for source-specific multicast. It maintains the relationship
between hosts and routers through IGMPv3.
In actual applications, part of IGMPv3 and PIM-SM techniques are adopted to implement the SSM
model. In the SSM model, because receivers have located a multicast source, no RP or RPT is
required. Multicast sources do not register with the RP, and the MSDP is not needed for discovering
multicast sources in other PIM domains.
Neighbor discovery
PIM-SSM uses the same neighbor discovery mechanism as PIM-SM. For more information, see
"Neighbor discovery."
DR election
PIM-SSM uses the same DR election mechanism as PIM-SM. For more information, see
election."
SPT building
The decision to build an RPT for PIM-SM or an SPT for PIM-SSM depends on whether the multicast
group that the receiver joins is in the SSM group range. The SSM group range reserved by IANA is
232.0.0.0/8.
Admin-scope 1 Admin-scope 3
G1 address
Global-scope
− −
G1 G2 address
Figure 41, the admin-scoped zones 1 and 2 have no intersection, but the
G3 address
Admin-scope 2
G2 address
100
"DR