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

Comprehensive and Detailed Explanation From Exact Extract (Nokia 7750 SR OS Routing Protocols Guide — OSPF LSA Types and Network Types):

Type 1 Router LSA — always generated, carries router topology info.

Type 2 Network LSA — generated only on broadcast or NBMA networks by DR.

Type 3 Summary LSA — used for inter-area route advertisement.

Type 5 External LSA — used for AS external routes (generated by ASBRs).

Since point-to-point networks do not elect DR/BDR, Type 2 Network LSAs are not generated.

Thus, correct answer: B.

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Comprehensive and Detailed Explanation From Exact Extract:

According to Nokia 7750 SR OS Routing Protocols Guide (OSPF Neighbor States and DR Election):

"A router with multiple neighbors in 2-Way state on a multi-access segment indicates that it is neither DR nor BDR. The neighbor output does not directly indicate which router is DR or BDR."

In the exhibit, R6 sees neighbors 10.10.10.2 in 2-Way state and 10.10.10.3, 10.10.10.5 in Full state.

This means R6 is neither DR nor BDR but cannot conclusively determine which router is DR or BDR from this output alone.

Therefore, correct answer is B.

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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