Cisco Exam 300-420 Topic 5 Question 84 Discussion

Actual exam question for Cisco's 300-420 exam

Question #: 84
Topic #: 5

[All 300-420 Questions]

In a multicast network, which condition must be met for an RPF check to be performed on the RP address'?

AThe PIM DM device receives a multicast packet and has no directly connected members

BThe PIM router or multilayer switch has a shared-tree state

CThe PIM router or multilayer switch has a source-tree state

DThe PIM DM device receives a multicast packet and has no directly connected PIM neighbor

Show Suggested Answer

Suggested Answer: B

by Arlene at Mar 21, 2024, 02:48 AM

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Maira

4 months ago

I think Beatriz is correct. A) The PIM DM device receives a multicast packet and has no directly connected members is the condition that must be met for an RPF check to be performed on the RP address.

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Beatriz

4 months ago

I see your point, Ilda. But I still think A is the right answer because in a multicast network, the RPF check is used to prevent loops.

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Ilda

5 months ago

I'm leaning towards option B) The PIM router or multilayer switch has a shared-tree state. It seems to make more sense to me.

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Maira

5 months ago

I disagree, I believe the answer is D) The PIM DM device receives a multicast packet and has no directly connected PIM neighbor.

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Beatriz

5 months ago

I think the answer is A) The PIM DM device receives a multicast packet and has no directly connected members.

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Craig

5 months ago

I'm not sure about the answer, but I think it might be C) because the RPF check is based on the source-tree state of the PIM router.

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Frank

5 months ago

I disagree, I believe the answer is D) because the RPF check is done when there are no directly connected PIM neighbors.

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Adell

5 months ago

I think the answer is A) because the RPF check is performed when there are no directly connected members receiving the multicast packet.

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Noel

6 months ago

I'm pretty sure the answer is B. The PIM router or multilayer switch needs to have a shared-tree state for the RPF check on the RP address to be performed. That makes sense to me.

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Lelia

5 months ago

That's a good point, I see where you're coming from. So the correct answer must be C - The PIM router or multilayer switch has a source-tree state.

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Tomas

5 months ago

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Chandra

5 months ago

I disagree, I believe it is A. The PIM DM device must receive a multicast packet with no directly connected members.

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Mona

5 months ago

I think it's actually D. The PIM DM device needs to receive a multicast packet with no directly connected PIM neighbor for the RPF check to happen.

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Kayleigh

5 months ago

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Stephaine

6 months ago

Ah, I see. The question is specifically asking about the condition for an RPF check on the RP address, not the source. That changes things a bit.

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Rima

6 months ago

Yes, that's a good point. The shared-tree state means the router is using the RP as the root of the multicast distribution tree, so the RPF check on the RP address would be necessary.

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Tammi

6 months ago

Yeah, that would be a pretty strange condition. I'm glad the actual answer seems to be B. It makes the most logical sense in the context of multicast routing.

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