Administrative Scoping Overview - HP 5920 series Configuration Manual

Administrative scoping overview

Typically, a PIM-SM domain contains only one BSR, which is responsible for advertising RP-set
information within the entire PIM-SM domain. The information about all multicast groups is forwarded
within the network that the BSR administers. This is called the "non-scoped BSR mechanism."
To implement refined management, you can divide a PIM-SM domain into a global-scoped zone and
multiple administratively-scoped zones (admin-scoped zones). This is called the "administrative scoping
mechanism."
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-scoped zones are divided for multicast groups. Zone border routers (ZBRs) form the boundary of
an admin-scoped zone. Each admin-scoped zone maintains one BSR, which serves multicast groups
within a specific range. Multicast protocol packets, such as assert messages and BSMs, for a specific
group range cannot cross the boundary of the admin-scoped zone that serves the group range. Multicast
group ranges that different admin-scoped zones serve can have intersections. However, the multicast
groups in an admin-scoped zone are valid only within the local zone, and theses multicast groups are
regarded as private group addresses.
The global-scoped zone maintains a BSR, which serves the multicast groups that do not belong to any
admin-scoped zones.
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 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.
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