Nokia 4A0-112 Exam - Topic 3 Question 3 Discussion

Actual exam question for Nokia's 4A0-112 exam

Question #: 3
Topic #: 3

Refer to the exhibit.

In the IS-IS network shown, router R1 has been configured to summarize subnetworks 20.20.1.0/24 and 20.20.2.0/24 as 20.20.0.0/16. Which routers' routing tables will be reduced, compared to their routing tables before the summarization?

ARouter R1

BRouter R2

CRouters R1 and R2

DRouters R2 and R4

Show Suggested Answer

Suggested Answer: B

Router R1 is the one that performs the summarization of the two subnets (20.20.1.0/24 and 20.20.2.0/24) into the summarized route 20.20.0.0/16. However, R1 itself will not see any change in its routing table because it is directly connected to both subnets and already knows about them.

Router R2, which is in Area 49.0002, will benefit from this summarization because it previously had separate routes for both 20.20.1.0/24 and 20.20.2.0/24. After the summarization, R2 will only need to maintain a single route to 20.20.0.0/16, reducing the size of its routing table.

Router R4 does not directly benefit from the summarization because it is only connected to the Level 1 network and has no need for the summarized routes from R1. Thus, the summarization does not affect R4's routing table.

by France at Jan 28, 2025, 12:13 AM

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Blair

3 months ago

Are we sure R2's table will actually be smaller?

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Santos

3 months ago

I think R1 and R2 both benefit from this.

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Wynell

3 months ago

Wait, how does this affect R4?

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Arthur

4 months ago

Definitely reduces R2's routing table!

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Irving

4 months ago

R1 is summarizing 20.20.1.0/24 and 20.20.2.0/24 as 20.20.0.0/16.

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Valentine

4 months ago

I feel like both R2 and R4 might benefit from the summarization, but I need to double-check how summarization works in IS-IS.

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Quentin

4 months ago

I practiced a similar question where summarization impacted multiple routers, but I can't recall if R1 is included in this case.

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Nieves

4 months ago

I think R2 will definitely have a reduced routing table since it will see the summarized route instead of the individual subnets.

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Dana

5 months ago

I remember that summarization reduces the number of routes in the routing table, but I'm not sure which routers are affected here.

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Alonzo

5 months ago

I'm a bit confused here. The question mentions that R1 is summarizing the subnets, but it's not clear to me how that affects the other routers. I'll need to think this through carefully and review my understanding of route summarization.

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Cortney

5 months ago

Alright, I've got this. The summarization on R1 will reduce the number of routes in the routing tables of the routers that are downstream from R1, which would be R2 and R4. The answer is D.

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Clare

5 months ago

Hmm, this seems like a tricky one. I'm not sure I fully understand the concept of route summarization and how it impacts the routing tables of different routers in the network. I'll need to review that before attempting to answer.

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Kristel

5 months ago

Okay, let's think this through. The question is asking which routers' routing tables will be reduced after the summarization on R1. I need to visualize the network and understand how the summarization affects the other routers.

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Dorthy

1 year ago

I'm going with C. Routing tables, reduced. Sounds like a job for the Routing Fairy!

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Gerri

11 months ago

Yeah, it's a good way to keep things more organized and efficient in the network.

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Truman

12 months ago

I think C is the correct answer too. Summarization can definitely help reduce routing tables.

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Van

1 year ago

C, obviously. R1 is the one doing the summarization, so of course R1 and R2 will have their routing tables reduced. Wait, did I just say 'obviously'? That was a rookie mistake.

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Carla

11 months ago

Agreed, C is the correct answer. R1 is the one summarizing, so R1 and R2 will have their routing tables reduced.

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Veronica

11 months ago

Definitely C. R1 is the one doing the summarization, so R1 and R2 will see a reduction in their routing tables.

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Paulene

11 months ago

Yeah, that makes sense. R1 is the one performing the summarization, so R1 and R2 will benefit from reduced routing tables.

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Fletcher

11 months ago

I think it's C too. R1 is the one doing the summarization, so R1 and R2 will have reduced routing tables.

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Launa

1 year ago

But wouldn't only router R1 have a reduced routing table since it's the one doing the summarization?

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Gracia

1 year ago

I agree with Arthur, because the subnetworks are being summarized by R1.

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Rupert

1 year ago

This is a tricky one! I'd go with C, but I can see how someone might think R2 or R4 could be affected too. Good question!

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Jolanda

1 year ago

Hmm, I'm not sure. I think it might be B since R2 is directly connected to the summarized subnets.

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Reed

1 year ago

B) Router R2

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Adria

1 year ago

A) Router R1

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Agustin

1 year ago

B) Router R2

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Bea

1 year ago

A) Router R1

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Arthur

1 year ago

I think routers R1 and R2 will have reduced routing tables.

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Vincent

1 year ago

The answer is clearly C. Routers R1 and R2 will have their routing tables reduced since the summarization is happening on R1, which is connected to both R2 and R4.

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Adelle

1 year ago

You're right, the correct answer is C) Routers R1 and R2.

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Floyd

1 year ago

No, I believe it is C) Routers R1 and R2.

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Mariko

1 year ago

I think the answer is A) Router R1.

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