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Figure 92
IPv6 multicast address format
An IPv6 admin-scoped zone with a larger scope field value contains an IPv6 admin-scoped zone
with a smaller scope field value. The zone with the scope field value of E is the IPv6 global-scoped
zone.
lists the possible values of the scope field.
Table 26
Values of the Scope field
Value Meaning
Remarks
0, F
Reserved
N/A
1 Interface-local
scope
N/A
2 Link-local
scope
N/A
3
Subnet-local scope
IPv6 admin-scoped zone.
4
Admin-local scope
IPv6 admin-scoped zone.
5
Site-local scope
IPv6 admin-scoped zone.
6, 7, 9 through D
Unassigned
IPv6 admin-scoped zone.
8
Organization-local scope
IPv6 admin-scoped zone.
E
Global scope
IPv6 global-scoped zone.
IPv6 PIM-SSM overview
The SSM model and the ASM model are opposites. The ASM model includes the IPv6 PIM-DM and IPv6
PIM-SM modes. The SSM model can be implemented by leveraging part of the IPv6 PIM-SM technique,
and it is also called "IPv6 PIM-SSM."
The SSM model provides a solution for source-specific multicast. It maintains the relationship between
hosts and routers through MLDv2.
In actual application, MLDv2 and part of IPv6 PIM-SM technique is adopted to implement the SSM model.
In the SSM model, receivers know exactly where an IPv6 multicast source is located by using
advertisements, consultancy, and so on. This mode does not required RP or RPT, and does not require a
source registration process for discovering IPv6 multicast sources in other IPv6 PIM domains.
The operating mechanism of IPv6 PIM-SSM is summarized as follows:
•
Neighbor discovery
•
DR election
•
SPT building