427
•
After receiving a BSMF that contains the RP-set information of one group range, a non-BSR
router updates corresponding RP-set information directly.
•
If the RP-set information of one group range is carried in multiple BSMFs, a non-BSR router
updates corresponding RP-set information after receiving all these BSMFs.
Because the RP-set information contained in each segment is different, loss of some IP fragments
will not result in dropping of the entire message.
Generally, a BSR performs BSM semantic fragmentation according to the MTU of its BSR interface.
However, the semantic fragmentation of BSMs originated due to learning of a new IPv6 PIM
neighbor is performed according to the MTU of the outgoing interface.
The function of BSM semantic fragmentation is enabled by default. A device that does not support
this function might regard a fragment as an entire message and learns only part of the RP-set
information. Therefore, if such devices exist in the IPv6 PIM-SM domain, you need to disable the
semantic fragmentation function on the C-BSRs.
To disable the BSM semantic fragmentation function:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter public network IPv6
PIM view or VPN instance
IPv6 PIM view.
pim
ipv6
[
vpn-instance
vpn-instance-name
]
N/A
3.
Disable the BSM semantic
fragmentation function.
undo bsm-fragment
enable
By default, the BSM semantic
fragmentation function is enabled.
Configuring IPv6 administrative scoping
With IPv6 administrative scoping disabled, an IPv6 PIM-SM domain has only one BSR. The BSR
manages the whole network. To manage your network more effectively and specifically, you can
partition the IPv6 PIM-SM domain into multiple IPv6 admin-scope zones. Each IPv6 admin-scope
zone maintains a BSR, which serves a specific IPv6 multicast group range. The IPv6 global scope
zone also maintains a BSR, which serves the IPv6 multicast groups with the Scope field in the group
addresses being 14.
Enabling IPv6 administrative scoping
Before you configure an IPv6 admin-scope zone, you must enable IPv6 administrative scoping.
Perform the following configuration on all routers in the IPv6 PIM-SM domain.
To enable IPv6 administrative scoping:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter public network IPv6
PIM view or VPN instance
IPv6 PIM view.
pim
ipv6
[
vpn-instance
vpn-instance-name
]
N/A
3.
Enable IPv6 administrative
scoping.
c-bsr admin-scope
Disabled by default.
Configuring an IPv6 admin-scope zone boundary
ZBRs form the boundary of each IPv6 admin-scope zone. Each admin-scope zone maintains a BSR,
which serves multicast groups with a specific Scope field in their group addresses. Multicast protocol
packets (such as assert messages and bootstrap messages) that belong to this range cannot cross
the admin-scope zone boundary.
