Nokia 4A0-C04 Exam - Topic 1 Question 80 Discussion

Actual exam question for Nokia's 4A0-C04 exam

Question #: 80
Topic #: 1

A confederated AS is comprised of three members. One member is comprised of 4 routers, while the other two members are comprised of 3 routers each. Assuming member ASs are fully meshed and use full mesh iBGP, what is the required number of BGP sessions within the confederation?

A12

B13

C14

D15

Show Suggested Answer

Suggested Answer: D

by Latanya at Mar 20, 2025, 09:18 AM

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Lizbeth

7 months ago

I think it’s actually 15 sessions total.

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Alaine

7 months ago

So that’s 12 sessions for the first AS and 9 for the others, right?

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Freeman

8 months ago

I’m not sure about that, seems like it could be 14.

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Elza

8 months ago

Wait, I thought it would be less than that!

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Ceola

8 months ago

There are 4 routers in one AS and 3 in the others.

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Doug

8 months ago

I’m leaning towards option C, but I’m not completely confident. I need to double-check how the sessions are counted between the AS members.

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Martina

8 months ago

I feel like the total number of sessions might be higher than I expect because of the different router counts in each member AS.

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Chauncey

9 months ago

I think we did a similar question about BGP sessions in a full mesh setup. If I recall correctly, it involves some combination of the routers in each AS.

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Natalie

9 months ago

I remember we calculated BGP sessions in class, but I'm not sure how to apply it to a confederation with different AS sizes.

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Elbert

9 months ago

I think I've got it! The key is to calculate the number of sessions for each member AS and then add them up. For the 4-router AS, that's 6 sessions. For the two 3-router ASs, that's 3 sessions each. So the total is 6 + 3 + 3 = 12 sessions.

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Ernie

9 months ago

I'm a bit confused on how to calculate the total number of sessions. Is it just a matter of adding up the sessions for each member AS?

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Chanel

9 months ago

Okay, let me break this down step-by-step. We have 3 member ASs, with 4, 3, and 3 routers respectively. For full mesh iBGP, each router needs a session with every other router in the confederation.

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Crista

10 months ago

Hmm, this looks like a tricky one. I'll need to think through the full mesh iBGP concept and how that applies to the different-sized member ASs.

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Lucille

1 year ago

The answer is clearly C) 14. Anyone who thinks otherwise must be living in a parallel universe where BGP sessions defy the laws of mathematics. Just sayin'.

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Judy

1 year ago

Exactly, no need to overcomplicate it. C) 14 is the correct answer.

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Oren

1 year ago

So, 4 routers x 6 sessions + 3 routers x 6 sessions + 3 routers x 6 sessions = 14 sessions in total.

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Nichelle

1 year ago

Yeah, it's simple math. 4 routers in one member, 3 in the other two members. Full mesh iBGP requires 6 sessions per router.

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Tamie

1 year ago

I agree, the answer is definitely C) 14.

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Adelle

1 year ago

Hmm, this is a tough one. I'm going to go with B) 13 just to mix things up a bit. Who knows, maybe I'll get lucky!

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Alyssa

1 year ago

I agree with you, I also think it's A) 12.

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Chanel

1 year ago

I think the answer is A) 12.

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Marjory

1 year ago

Whoa, this is a tricky one! Let me see... Okay, I've got it - the answer is C) 14. Gotta love those BGP sessions, am I right?

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Della

1 year ago

Definitely C) 14. This is a classic confederation topology problem, and the math checks out. Nice try with the other options, though!

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Chaya

1 year ago

Because each router in the fully meshed member ASs needs to establish a session with every router in the other member ASs, so it's 4 routers x 3 routers + 3 routers x 3 routers = 12 + 9 = 21. But since iBGP sessions are not required within the same member AS, we subtract 7 (3 routers x 2 sessions) to get 14.

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Rodrigo

1 year ago

Why do you think it's 14?

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Chaya

1 year ago

I disagree, I believe the answer is C) 14.

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Elmira

1 year ago

I think the answer is C) 14. It makes sense since each member AS has a full mesh of iBGP sessions, and with three members, that's 9 sessions plus the 5 sessions between the members.

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