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multicast groups within a specific range. Multicast protocol packets, such as assert messages and
bootstrap messages, for a specific group range cannot cross the admin-scope zone boundary.
Multicast group ranges that different admin-scope zones serve can be overlapped. A multicast group
is valid only within its local admin-scope zone, and functions as a private group address.
The global scope zone maintains a BSR, which serves the multicast groups that do not belong to any
admin-scope zone.
Relationship between admin-scope zones and the global scope zone
The global-scoped zone and each admin-scoped zone have their own C-RPs and BSRs. These
devices are effective only on their respective zones, and the BSR election and the RP election are
implemented independently. Each admin-scoped zone has its own boundary. The multicast
information within a zone cannot cross this boundary in either direction. You can have a better
understanding of the global-scoped zone and admin-scoped zones based on geographical spaces
and multicast group address ranges.
•
In view of geographical locations:
An admin-scope zone is a logical zone for particular multicast groups. The multicast packets for
such multicast groups are confined within the local admin-scope zone and cannot cross the
boundary of the zone.
Figure 49 Relationship in view of geographical locations
As shown in
, for the multicast groups in a specific group address range, the
admin-scope zones must be geographically separated and isolated. A router cannot belong to
multiple admin-scope zones. In other words, different admin-scope zones contain different
routers. However, the global-scoped zone includes all routers in the PIM-SM domain or
BIDIR-PIM domain. Multicast packets that do not belong to any admin-scope zones are
forwarded in the entire PIM-SM domain or BIDIR-PIM domain.
•
In view of multicast group address ranges:
Each admin-scope zone serves specific multicast groups, of which the multicast group
addresses are valid only within the local zone. The multicast groups of different admin-scoped
zones might have intersections. All the multicast groups other than those of the admin-scoped
zones are served by the global-scoped zone.
