H3C Technologies H3C S12500 Series Switches - Manual (Page 395)

379
IPv6 admin-scoped zone maintains one BSR to provide services for multicast groups within a specific
scope. IPv6 multicast protocol packets, such as assert messages and bootstrap messages, for a specific
group range cannot cross the IPv6 admin-scoped zone boundary. IPv6 multicast group ranges to which
different IPv6 admin-scoped zones are designated can overlap. An IPv6 multicast group is valid only
within its local IPv6 admin-scoped zone, functioning as a private group address.
The IPv6 global-scoped zone maintains a BSR to provide services for the IPv6 multicast groups with the
Scope field in their group addresses being 14.
Relationship between IPv6 admin-scoped zones and the IPv6 global-scoped zone
The IPv6 global-scoped zone and each IPv6 admin-scoped zone have their own C-RPs and BSRs. These
devices are effective only in their respective IPv6 admin-scoped zones. BSR election and RP election are
implemented independently within each IPv6 admin-scoped zone. Each IPv6 admin-scoped zone has its
own boundary. The multicast information cannot cross this border in either direction. A better
understanding of the IPv6 global-scoped zone and IPv6 admin-scoped zones should be based on
geographical space and group address range.
• In view of geographical space:
IPv6 admin-scoped zones are logical zones specific to particular multicast groups. The multicast
packets of these multicast groups are confined within the local IPv6 admin-scoped zone and
cannot cross the boundary of the zone.
Figure 106 Relationship between admin-scoped zones and the global-scoped zone in geographic
space
As shown in Figure 106 , for multicast groups with the same Scope field in their group addresses,
IPv6 admin-scoped zones must be geographically separated from one another. A router must not
provide services for different admin-scoped zones. Different admin-scoped zones contain different
routers, whereas the global-scoped zone covers all routers in the IPv6 PIM-SM domain. Multicast
packets that do not belong to any admin-scoped zones can be transmitted in the entire IPv6
PIM-SM domain.
• In view of multicast group address Scope field:
As shown in
Figure 107 , the Scope field in each IPv6 multicast group address indicates the
admin-scoped zone to which the corresponding multicast group to.