F3726, F3211, F3174, R5135, R3816-HP Firewalls and UTM Devices Appendix Protocol Reference-6PW100

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To implement refined management, you can divide a PIM-SM domain into one global scope zone and
multiple administratively scoped zones (admin-scope zones). This is called the "administrative scoping
mechanism."
The administrative scoping mechanism effectively releases stress on the management in a single-BSR
domain and enables provision of zone-specific services through private group addresses.
Admin-scope zones are divided specific to multicast groups. Zone border routers (ZBRs) form the
boundary of the admin-scope zone. Each admin-scope zone maintains one BSR, which serves 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 to 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 locations 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 58 Relationship in view of geographical locations
As shown in Figure 58, 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. Multicast packets
that do not belong to any admin-scope zones are forwarded in the entire PIM-SM domain.
• In view of multicast group address ranges: