Nokia 4A0-105 Exam - Topic 2 Question 108 Discussion

Actual exam question for Nokia's 4A0-105 exam

Question #: 108
Topic #: 2

Click on the exhibit below.

Assume a CE router is connected to the SAP of each PE. The arp cache of all CE routers is empty and the FDB for VPLS 300 is empty. The CE router connected to PE-A initiates a ping towards the CE router connected to PE-C. The ping is successful. Which of the following statements are true? (Choose 2)

AThe FDB on PE-A will contain entries for all CE routers.

BThe FDB on PE-B will contain an entry for the CE router connected to PE-A.

CThe FDB on PE-B will contain an entry for all CE routers.

DThe FDB on PE-C will contain entries for the CE router connected to PE-A and the CE router connected to PE-C.

Show Suggested Answer

Suggested Answer: A

by Mila at Mar 06, 2025, 01:57 PM

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Georgeanna

5 months ago

I’m not sure about that, seems like a stretch to say PE-B has all CE entries.

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Chantell

5 months ago

Totally agree, PE-C needs to know about both CE routers for the ping to work!

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Aleisha

5 months ago

Wait, how can the FDB on PE-A have entries for all CE routers if the arp cache is empty?

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Brandon

5 months ago

I think the FDB on PE-B will only have the entry for CE-A, not all CE routers.

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Lashaunda

6 months ago

The FDB on PE-C will definitely have entries for both CE routers.

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Gilma

6 months ago

I’m pretty sure that PE-A will only have entries for the CE routers that it directly communicates with, but I can't recall if that means it will have all CE routers listed.

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Wai

6 months ago

I’m a bit confused about whether PE-B will have entries for all CE routers or just the one that sent the ping. I need to think about how the traffic is routed.

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Sherrell

6 months ago

This question feels similar to one we practiced where we had to determine FDB entries based on traffic flow. I think the FDB on PE-C will definitely have entries for both CE routers.

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Elmira

6 months ago

I remember something about FDB entries being created when a device sends traffic, but I'm not sure if it applies to all CE routers or just the one initiating the ping.

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Kenny

6 months ago

I'm a bit confused about the expected FDB entries on each PE router. I'll need to carefully consider the options and try to logically deduce which ones are true based on the information provided.

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Eric

6 months ago

Okay, let me think this through step-by-step. The CE router's ARP cache is empty, so the initial ARP request would have been flooded to all PEs. The successful ping means the FDB on at least one PE must have been updated with the MAC addresses of the CE routers.

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Freeman

6 months ago

Hmm, the key here is that the ping from the CE router connected to PE-A to the CE router connected to PE-C was successful. This means the FDB on the PE routers must have been populated correctly to allow the traffic to flow.

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Paulene

7 months ago

This question seems to be testing my understanding of VPLS and how the FDB (Forwarding Database) is populated on the PE routers. I'll need to carefully consider the information provided and think through the expected behavior.

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Willard

12 months ago

PE-B's FDB is like the unpopular kid at the party - everyone else is having a good time, but it's just sitting in the corner, feeling lonely and forgotten.

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Karl

11 months ago

D) The FDB on PE-C will contain entries for the CE router connected to PE-A and the CE router connected to PE-C.

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Mabel

12 months ago

A) The FDB on PE-A will contain entries for all CE routers.

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Billy

12 months ago

B and D seem like the correct answers here. I'm glad they didn't ask about the CE routers' arp caches - that would've been a real head-scratcher!

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Fletcher

12 months ago

I'm picturing the PEs as a bunch of gossips, with PE-A and PE-C knowing all the juicy details about the CE routers, while poor PE-B is left out of the loop. Classic VPLS drama!

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Rosenda

12 months ago

Hmm, I guess the ping creates a MAC address learning process, but I'm not sure how that affects the FDBs on the other PEs. Time to review my VPLS notes!

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Werner

10 months ago

Tracey: So, the ping does affect the FDBs on the other PEs. Interesting!

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Felicia

10 months ago

User 3: I remember reading that the FDB on PE-C will have entries for both CE routers connected to PE-A and PE-C.

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Tracey

11 months ago

User 2: Yeah, that sounds right. I believe the FDB on PE-B will only have an entry for the CE router connected to PE-A.

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Emilio

11 months ago

User 1: I think the FDB on PE-A will have entries for all CE routers.

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Marica

1 year ago

I'm not sure about option C, but I think option D is true because the FDB on PE-C should have entries for both CE routers connected to PE-A and PE-C.

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Micah

1 year ago

I agree with you, Francesco. Option B might also be true because the FDB on PE-B should have an entry for the CE router connected to PE-A.

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Luz

1 year ago

A successful ping means the FDB on PE-A and PE-C will have entries for the CE routers involved, but PE-B's FDB will only have an entry for the CE router connected to PE-A.

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