Nokia 4A0-100 Exam - Topic 4 Question 124 Discussion

Actual exam question for Nokia's 4A0-100 exam

Question #: 124
Topic #: 4

[All 4A0-100 Questions]

Which of the following routing protocols cannot be used between routers R2 and R4?

AStatic Routing

BIS-IS

COSPF

DeBGP

Show Suggested Answer

Suggested Answer: D

In the diagram:

R2 and R4 are both within AS 65540, which indicates that they are in the same Autonomous System.

eBGP (External Border Gateway Protocol) is designed for routing between different ASes (inter-AS routing).

Since R2 and R4 are in the same AS, you would use:

OSPF or IS-IS (both interior gateway protocols -- IGPs)

Static routing is also valid between any two routers if manually configured

eBGP is invalid between routers in the same AS.

The correct protocol in that case would be iBGP (internal BGP) if BGP were to be used within the AS.

Therefore, the correct answer is: D. eBGP

Nokia IP Routing Fundamentals -- BGP vs IGP

Nokia SRA Guide -- AS Concepts and Protocol Suitability

RFC 4271 -- BGP Specification

by Johnna at Apr 10, 2026, 07:25 PM

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2 days ago

I practiced a similar question where OSPF was the answer, but I can't recall if it applies here too.

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7 days ago

I think I remember that static routing can definitely be used, but I'm not sure about IS-IS.

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