Configuring A Bsr - 3Com MSR 50 Series Configuration Manual

1250 C 74: IP 6 PIM C
HAPTER V
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Configuring a BSR

n
ONFIGURATION
To do...
Enter system view
Enable IPv6 multicast routing
Enter interface view
Enable IPv6 PIM-SM
CAUTION: All the interfaces of the same device must work in the same IPv6 PIM
mode.
The BSR is dynamically elected from a number of C-BSRs. Because it is
unpredictable which router will finally win a BSR election, the commands
introduced in this section must be configured on all C-BSRs.
Performing basic C-BSR configuration
An IPv6 PIM-SM domain can have only one BSR, but must have at least one C-BSR.
Any router can be configured as a C-BSR. Elected from C-BSRs, a BSR is
responsible for collecting and advertising RP information in the IPv6 PIM-SM.
C-BSRs should be configured on routers in the backbone network. When
configuring a router as a C-BSR, make sure that router is IPv6 PIM-SM enabled.
The BSR election process is as follows:
Initially, every C-BSR assumes itself to be the BSR of this IPv6 PIM-SM domain,
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and uses its interface IPv6 address as the BSR address to send bootstrap
messages.
When a C-BSR receives the bootstrap message of another C-BSR, it first
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compares its own priority with the other C-BSR's priority carried in the
message. The C-BSR with a higher priority wins. If there is a tie in the priority,
the C-BSR with a higher IPv6 address wins. The loser uses the winner's BSR
address to replace its own BSR address and no longer assumes itself to be the
BSR, while the winner keeps its own BSR address and continues assuming itself
to be the BSR.
Configuring a legal range of BSR addresses enables filtering of BSR messages
based on the address range, thus to prevent malicious hosts from initiating attacks
by disguising themselves as legitimate BSRs. To protect legitimate BSRs from being
maliciously replaced, preventive measures are taken specific to the following two
situations:
1 Some malicious hosts intend to fool routers by forging BSR messages and change
the RP mapping relationship. Such attacks often occur on border routers. Because
a BSR is inside the network whereas hosts are outside the network, you can
protect a BSR against attacks from external hosts by enabling border routers to
Use the command...
system-view
multicast ipv6
routing-enable
interface interface-type
interface-number
pim ipv6 sm
Remarks
-
Required
Disable by default
-
Required
Disabled by default