436
Step Command
Remarks
The BS period value must be
smaller than the BS timeout timer.
4.
Configure the BS timeout
timer.
c-bsr holdtime
interval
Optional.
By default, the BS timeout timer is
determined by the formula "BS
timeout timer = BS period × 2 +
10." The default BS period is 60
seconds, so the default BS
timeout timer is 60 × 2 + 10 = 130
(seconds).
Disabling BSM semantic fragmentation
Generally, a BSR periodically distributes the RP-set information in bootstrap messages within the
IPv6 BIDIR-PIM domain. It encapsulates a BSM in an IP datagram and might split the datagram into
fragments if the message exceeds the MTU. In respect of such IP fragmentation, 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 BSMFs.
•
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 PIM neighbor is
performed according to the MTU of the outgoing interface.
The function of BSM semantic fragmentation is enabled by default. Devices not supporting this
function might deem a fragment as an entire message, thus learning only part of the RP-set
information. Therefore, if such devices exist in the IPv6 BIDIR-PIM domain, you must 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 IPv6 PIM view.
pim ipv6
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 administrative scoping disabled, an IPv6 BIDIR-PIM domain has only one BSR. The BSR
manages the whole network. To manage your network more effectively and specifically, you can
partition the IPv6 BIDIR-PIM domain into multiple admin-scope zones. Each admin-scope zone
maintains a BSR, which serves a specific multicast group range. The global scope zone also
maintains a BSR, which serves the rest multicast groups.
Enabling IPv6 administrative scoping
Before you configure an IPv6 admin-scope zone, you must enable IPv6 administrative scoping first.
