HP A6600 Configuration Manual page 127

To do...
4. Configure the BS timeout.
BS period and timeout settings
Make sure that the BS period value is smaller than the BS timeout value.
The BS period defaults to the value determined by the formula:
"BS period = (BS timeout – 10) / 2". The default BS timeout is 130 seconds, so the default BS period =
(130 – 10) / 2 = 60 (seconds)
The BS timeout setting defaults to the value determined by the formula:
"BS timeout = BS period × 2 + 10". The default BS period is 60 seconds, so the default BS timeout = 60
× 2 + 10 = 130 (seconds)
Disabling BSM semantic fragmentation
Generally, a BSR periodically distributes the RP-set information in bootstrap messages within the PIM-SM
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.
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 PIM-SM domain, you need to disable the semantic fragmentation function on
the C-BSRs.
To do...
Enter system view
Enter public network PIM view or
VPN instance PIM view
Disable the BSM semantic
fragmentation function
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.
Use the command...
c-bsr holdtime interval
Use the command...
system-view
pim [ vpn-instance
vpn-instance-name ]
undo bsm-fragment enable
116
Remarks
Optional
For the default value, see below.
Remarks
—
—
Required
By default, the BSM semantic
fragmentation function is enabled.