Juniper Exam JN0-351 Topic 4 Question 47 Discussion

Actual exam question for Juniper's JN0-351 exam

Question #: 47
Topic #: 4

You are an operator for a network running 1S-IS. Two routers are failing to form an adjacency. What are two reasons for this problem? (Choose two.)

AThere are mismatched router IDs on the L2 routers.

BThere is no configured ISO address on any IS-IS interface.

CThere is a mismatched area ID between the L2 routers.

DThe family iso configuration is missing from the adjacency interface.

Show Suggested Answer

Suggested Answer: B, D

The two reasons for the failure to form an adjacency in a network running IS-IS could be:

B) There is no configured ISO address on any IS-IS interface.IS-IS requires each router interface to have an ISO address configured.Without this address, the routers cannot form an adjacency1.

D) The family iso configuration is missing from the adjacency interface.The 'family iso' configuration is essential for IS-IS to function correctly.If this configuration is missing from the adjacency interface, it could prevent the formation of an adjacency1.

These explanations are based on the Enterprise Routing and Switching Specialist (JNCIS-ENT) documents and learning resources available at Juniper Networks23.

by Deangelo at Aug 12, 2025, 05:32 PM

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Aimee

5 days ago

I remember something about mismatched area IDs causing adjacency issues, so maybe option C is a good choice.

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Miriam

11 days ago

This seems straightforward. The key is to identify any mismatches in the router ID or area ID between the two routers. That's probably the issue here.

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Twana

16 days ago

I'm a bit confused on this one. I know it's related to the IS-IS configuration, but I'm not sure which specific settings could be causing the problem.

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