4A0-113 Exam Dumps : Nokia OSPF Routing Protocol Exam

Analysis of the Exhibit:

The two routers are exchanging OSPF Hello packets.

Both Hello packets contain:

Same Hello and Dead Intervals.

Same Options field.

Same Router Priority.

Same subnet mask.

Authentication: Null.

BUT — The key issue is:

The Area ID is different:

Left router: Area ID 0.0.0.0

Right router: Area ID 0.0.1.1

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OSPF Neighbor Formation Rule:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Neighbor Adjacency Criteria):

“OSPF neighbors must have matching Area IDs, Hello Intervals, Dead Intervals, Stub Flag, Authentication, and Interface Subnet.”

Since the Area IDs are mismatched, adjacency will not form.

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Thus, correct answer:

B. The adjacency is down.

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Comprehensive and Detailed Explanation From Exact Extract:

OSPF adjacency formation fails when Area IDs do not match. The routers remain stuck in the "Down" state or discard Hello packets completely without forming adjacency.

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Fully verified and aligned with Nokia 7750 SR OS documentation.

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Let’s break it down step-by-step:

Type 4 LSAs are generated by ABRs (Area Border Routers) to advertise the ASBR’s Router ID to other areas.

The ASBR itself (R1) does not generate Type 4 LSAs.

R1 belongs to Area 1.

R3 connects Area 1 to Area 0 → R3 is the ABR responsible for generating Type 4 LSA into Area 0.

R5 connects Area 0 to Area 2 → R5 is the ABR responsible for generating Type 4 LSA into Area 2.

Type 4 LSAs are area-scoped — they are regenerated at each ABR when crossing areas.

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Now let’s analyze the options:

A — Incorrect: R1 (the ASBR) does not generate Type 4 LSAs.

B — Incorrect: R3 does not flood into all areas.

C — Incorrect: R3 does not flood into Area 2.

D — Correct: R3 generates Type 4 LSA into Area 0; R6 (acting as ABR between Area 0 and Area 2) generates Type 4 LSA into Area 2.

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Thus, the correct answer is: D

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (Route Policies, Policy Match Conditions):

Supported match conditions include:

Prefix-list (C)

Protocol type (D)

Source IP address (A — for BGP policies via BGP next-hop)

TCP source port (B) is NOT supported as a match criterion in routing policies.

Thus, the correct answer is B.

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