Click the Exhibit button.
Referring to the exhibit, you have a network that uses PIM-SM and you need to block certain PIM register
messages.
Which two statements are correct in this situation? (Choose two.)
A.
You should apply a policy that blocks PIM register messages from the source on R4.
B.
You should apply a policy that blocks PIM register messages from the source on R3.
C.
You should apply a policy that blocks PIM register messages from the source on R2.
D.
You should apply a policy that blocks PIM register messages from the source on R1.
Explanation:
You can filter Protocol Independent Multicast (PIM) register messages sent from the designated router (DR) or
to the rendezvous point (RP).Note: In a shared tree, the root of the distribution tree is a router, not a host, and is located somewhere in the
core of the network. In the primary sparse mode multicast routing protocol, Protocol Independent Multicast
sparse mode (PIM SM), the core router at the root of the shared tree is the rendezvous point (RP).
http://www.juniper.net/documentation/en_US/junos15.1/topics/example/ospf-designated-routerelection-configuring.html
Answer could be A, D, what do you think about this ?
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A, B sorry, PIM register and send by the receiver Designated router to the RP router.
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A and D is connect…..first on RP and then at DR where source is connected too.
B is incorrect, it can not be at receiver side…
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A&D
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Configuring Register Message Filters on a PIM RP and DR
You can apply register message filters on a DR to control outgoing register messages, or apply them on an RP to control incoming register messages.
https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/mcast-filter-pim-rp-dr.html
In a PIM sparse mode (PIM-SM) domain, there are two types of designated routers to consider:
The receiver DR sends PIM join and PIM prune messages from the receiver network toward the RP.
The source DR sends PIM register messages from the source network to the RP.
https://www.juniper.net/documentation/en_US/junos/topics/concept/multicast-pim-designated-router-types.html
DR are used to avoid loops, duplicate joins, etc.
The DR is like a next hop to get not only to the multicast source, this is the next hop to get to the Multicast Tree and to a multicast router called RP, this is not the source, but have the multicast tree control capability, and often will be near to the source.
https://forums.juniper.net/t5/Routing/multicast-Designated-Router/td-p/137073
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Option A and D, final answer.
From the exhibit;
R1 is the Source DR, The only job of the Source DR is to send PIM register messages to the RP.
R3 is the Receiver DR, The job of the receiver DR is to send PIM join and PIM prune messages from the client(receiver)
towards the RP.
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