HP MSR2003 Configuration Manual page 315

Step
4. (Optional.) Configure a legal
BSR address range.
Configuring an IPv6 PIM domain border
As the administrative core of an IPv6 BIDIR-PIM domain, the BSR sends the collected RP-set information
in the bootstrap messages to all routers in the IPv6 BIDIR-PIM domain.
An IPv6 PIM domain border is a bootstrap message boundary. Each BSR has its specific service scope.
IPv6 PIM domain border interfaces partition a network into different IPv6 BIDIR-PIM domains. Bootstrap
messages cannot cross a domain border in either direction.
Perform the following configuration on routers that you want to configure as an IPv6 PIM domain border.
To configure an IPv6 PIM border domain:
Step
1. Enter system view.
2. Enter interface view.
3. Configure an IPv6 PIM
domain border.
Disabling the BSM semantic fragmentation function
Generally, a BSR periodically advertises the RP-set information in BSMs within the IPv6 BIDIR-PIM domain.
It encapsulates a BSM in an IPv6 datagram. When a BSM exceeds the MTU, it is split into multiple BSM
fragments (BSMFs). In this case, the loss of a single IP fragment leads to unavailability of the entire
message.
Semantic fragmentation of BSMs can solve this issue. When a non-BSR router receives a BSMF, it
examines the RP-set information for an IPv6 multicast group range:
• If the RP-set information is carried in one BSMF, the router directly updates the RP-set information for
the group range.
If the RP-set information is carried in multiple BSMFs, the router updates the RP-set information for the
•
group range after receiving all these BSMFs. The loss of some IP fragments does not result in
dropping of the entire BSM.
The BSM semantic fragmentation function is enabled by default. A device that does not support this
function might regard a fragment as a BSM. Therefore, the device learns only part of the RP-set
information. If such devices exist in the IPv6 BIDIR-PIM domain, you must disable the BSM semantic
fragmentation function on the C-BSRs.
To disable the BSM semantic fragmentation function:
Step
1. Enter system view.
2. Enter IPv6 PIM view.
3. Disable the BSM semantic
fragmentation function.
Command
bsr-policy acl6-number
Command
system-view
interface interface-type
interface-number
ipv6 pim bsr-boundary
Command
system-view
ipv6 pim [ vpn-instance
vpn-instance-name ]
undo bsm-fragment enable
305
Remarks
By default, no restrictions are
defined.
Remarks
N/A
N/A
By default, no PIM domain border is
configured.
Remarks
N/A
N/A
By default, BSM semantic
fragmentation is enabled.