Ipv6 Administrative Scoping Overview - HP 5920 series Configuration Manual

To eliminate these weaknesses, IPv6 PIM-SM allows an RP or the receiver-side DR to initiate a switchover
to SPT:
The RP initiates a switchover to SPT:
•
When the RP receives the first multicast packet, it sends an (S, G) source-specific join message hop
by hop toward the IPv6 multicast source. The routers along the path from the RP to the IPv6
multicast source constitute an SPT branch. The subsequent IPv6 multicast data for the IPv6 multicast
group can be forwarded to the RP along the branch without being encapsulated in register
messages.
For more information about the switchover to SPT initiated by the RP, see
registration."
• The receiver-side DR initiates a switchover to SPT:
When the receiver-side DR receives the first multicast packet, it initiates a switchover to SPT as
follows:
The receiver-side DR sends an (S, G) source-specific join message hop by hop toward the IPv6
a.
multicast source. The routers along the path from the RP to the source-side DR create an (S, G)
entry in their forwarding table to constitute an SPT branch.
When the multicast packets for the IPv6 multicast group are forwarded to the router where the
b.
RPT and the SPT branches, the router drops the multicast packets that reach it along the RPT and
sends a prune message with the RP bit hop by hop to the RP. After receiving the prune message,
the RP forwards it toward the IPv6 multicast source (supposed only one receiver exists). Thus,
the switchover to SPT is completed.
Finally, the IPv6 multicast source sends the multicast packets for the IPv6 multicast group to the
c.
receiver along the SPT.
With the switchover to SPT, IPv6 PIM-SM builds SPTs more economically than IPv6 PIM-DM does.
Assert
IPv6 PIM-SM uses a similar assert mechanism as IPv6 PIM-DM does. For more information, see "Assert."

IPv6 administrative scoping overview

Typically, an IPv6 PIM-SM domain contains only one BSR, which is responsible for advertising RP-set
information within the entire IPv6 PIM-SM domain. The information about all IPv6 multicast groups is
forwarded within the network that the BSR administers. This is called the "IPv6 non-scoped BSR
mechanism."
To implement refined management, you can divide an IPv6 PIM-SM domain into an IPv6 global-scoped
zone and multiple IPv6 administratively-scoped zones (admin-scoped zones). This is called the "IPv6
administrative scoping mechanism."
IPv6 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.
An IPv6 admin-scoped zone serves particular IPv6 multicast groups with the same scope field value in
their group addresses. Zone border routers (ZBRs) form the boundary of an IPv6 admin-scoped zone.
Each IPv6 admin-scoped zone maintains one BSR, which serves IPv6 multicast groups with the same
scope field value. IPv6 multicast protocol packets, such as assert messages and BSMs, of these IPv6
multicast groups cannot cross the boundary of the IPv6 admin-scoped zone that serves the group range.
The IPv6 multicast group ranges that different IPv6 admin-scoped zones serve can have intersections, but
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"IPv6 multicast source