HP 6125XLG - Page 312

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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:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A
3. Configure an IPv6 PIM
domain border.
ipv6 pim bsr-boundary
By default, no PIM domain border is
configured.
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). 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, a non-BSR 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:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter IPv6 PIM view.
ipv6 pim [ vpn-instance
vpn-instance-name ]
N/A
3. Disable the BSM
semantic fragmentation
function.
undo bsm-fragment enable
By default, BSM semantic
fragmentation is enabled.
NOTE:
Generally, a BSR performs BSM semantic fragmentation according to the MTU of its BSR interface. For
BSMs originated due to learning of a new IPv6 PIM neighbor, semantic fragmentation is performed
according to the MTU of the interface that sends the BSMs.