HP 6125XLG R2306-HP 6125XLG Blade Switch IP Multicast Configuration Guide - Page 162

Step 3. Configuring an IPv6 PIM domain border. Command ipv6 pim bsr-boundary Remarks By default, no IPv6 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 PIM-SM domain. It encapsulates a BSM in an IPv6 datagram and might fragment the datagram if the message exceeds the MTU. In this case, loss of a single IP fragment leads to unavailability of the entire message. Semantic fragmentation of BSMs can solve this issue. When a BSM exceeds the MTU, it is split to multiple BSM fragments (BSMFs). • If the RP-set information for an IPv6 multicast group range is carried in one BSMF, a non-BSR router directly updates the RP-set information for the group range after receiving the BSMF. • If the RP-set information for an IPv6 multicast group range is carried in multiple BSMFs, a non-BSR router updates the RP-set information for the group range after receiving all these BSMFs. Because the RP-set information contained in each segment is different, 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 and thus learns only part of the RP-set information. Therefore, if such devices exist in the IPv6 PIM-SM 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 system-view ipv6 pim undo bsm-fragment enable Remarks N/A N/A By default, BSM semantic fragmentation is enabled. NOTE: Generally, a BSR performs BSM semantic fragmentation according to the MTU of its BSR interface. However, 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. Configuring IPv6 multicast source registration In an IPv6 PIM-SM domain, the source-side DR sends register messages to the RP, and these register messages have different IPv6 multicast source or IPv6 multicast group addresses. You can configure a filtering rule to filter register messages so that the RP can provide services for specific IPv6 multicast groups. If the filtering rule denies an (S, G) entry, or if the filtering rule does not define an action for this entry, the RP sends a register-stop message to the DR to stop the registration process for the IPv6 multicast data. In view of information integrity of a register message in the transmission process, you can configure the device to calculate the checksum based on the entire register message. However, to reduce the workload of encapsulating data in register messages and for the sake of interoperability, do not use this checksum calculation method. 155