3Com Router 3031, Command Reference Manual

Page: 711 / 838

PIM Configuration Commands 711
undo crp-policy
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Parameter
acl-number: ACL number used by C-RP filter policy, ranging from 100 to 199.
Description
Using the crp-policy command, you can restrict the range for valid C-RP and the
group range served by each C-RP so as to prevent C-RP cheating. Using the undo
crp-policy command, you can restore the normal state without any range
restriction and regard all the messages received are valid.
In PIM SM network which uses BSR mechanism, any router can set itself as a C-RP
serving the specific group range. If it is elected in RP election, it will become an RP
serving in the group range.
In BSR mechanism C-RP router unicasts C-RP information to BSR router which is
responsible for advertising all C-RP information to the whole network by using BRP
information.
To prevent C-RP cheating, crp-policy is needed to be configured on BSR router to
restrict the range for valid C-RP and the group address range it serves. Each C-BSR
may become a BSR possibly, so the same filter policy should be configured on each
C-BSR.
This command uses the ACL numbered from 100 to 199. The parameter source in
the related rule command indicates C-RP address and destination indicates the
group range the C-RP serves. Upon matching the received C-RP message, only
when the C-RP address in the packet matches source address and the group
address range in the packet is the subset of that in ACL, can this configuration be
regarded successful.
For the related commands, see acl and rule.
Example
Configure C-RP policy on C-BSR router. Only permit 1.1.1.1/32 to act as C-RP
which only serves the group range 225.1.0.0/16.
<3Com-pim] crp-policy 100
<3Com-pim] quit
<3Com] acl number 100
<3Com-acl-adv-100] rule 0 permit ip source 1.1.1.1 0 destination
225.1.0.0 0.0.255.255
debugging pim common Syntax
debugging pim common { all | event | packet | timer }
undo debugging pim common { all | event | packet | timer }
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