Configuring c-bsr timers, Disabling bsm semantic fragmentation – H3C Technologies H3C S12500 Series Switches User Manual

Page 406

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Step

Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enter IPv6 PIM view.

pim ipv6

N/A

3.

Configure the hash mask

length.

c-bsr hash-length hash-length

Optional.
126 by default.

4.

Configure the C-BSR priority. c-bsr priority priority

Optional.
64 by default.

Configuring C-BSR timers

The BSR election winner multicasts its own IPv6 address and RP-Set information throughout the region to

which it is designated through bootstrap messages. The BSR floods bootstrap messages throughout the
network at the interval of the BS (BSR state) period. Any C-BSR that receives a bootstrap message retains

the RP-set for the length of BS timeout, during which no BSR election occurs. If the BSR state times out and

no bootstrap message is received from the BSR, a new BSR election process begins among the C-BSRs.
Perform the following configuration on C-BSR routers. If you set values for the BS period and the BS
timeout timer, the system uses the configured ones instead of the default ones.
To configure C-BSR timers:

Step Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enter IPv6 PIM view.

pim ipv6

N/A

3.

Configure the BS period.

c-bsr interval interval

Optional.
By default, the BS period is

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).
In configuration, make sure that the
BS period is smaller than the BS

timeout value.

4.

Configure the BS timeout.

c-bsr holdtime interval

Optional.
By default, the BS timeout value is

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 IPv6

PIM-SM domain. It encapsulates a BSM in an IPv6 datagram and might split the datagram into fragments

if the message exceeds the maximum transmission unit (MTU). In respect of such IP fragmentation, loss of

a single IP fragment leads to unavailability of the entire message.

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