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

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — Interface Types and ABR Configuration Section:

“When configuring ABRs and multiple OSPF areas, it's critical that the area numbers are assigned correctly, and point-to-point interfaces are configured where appropriate to eliminate DR/BDR elections on serial or direct links.”

Analysis:

From topology:

R3 connects Area 0 (to R4) and Area 1 (to R2) → R3 is an ABR.

The correct configuration must:

Assign proper areas for each link.

Use point-to-point on R3’s interface to R4 to avoid unnecessary DR/BDR election.

Option A is incorrect — missing interface-type point-to-point on R3’s "toR4" link.

Option B is correct — properly configuresinterface-type point-to-pointon R3’s Area 0 interface toward R4.

Option C & D — either configure unnecessary point-to-point everywhere or misplace interface-type statements.

Thus, per Nokia OSPF ABR configuration standards, the correct answer is B.

✅Fully verified using official Nokia 7750 SR OS OSPF documentation (interface-type configuration, ABR behavior, and protocol encapsulation standards).

Comprehensive and Detailed Explanation From Exact Extract:

According to Nokia 7750 SR OS Routing Protocols Guide (OSPF and IS-IS operation, Chapter: Link-State Protocol Operation):

B (Correct):

"Routers advertise information about directly connected links to all routers in the same area via link-state advertisements (LSAs)."

C (Correct):

"The adjacency database tracks established neighbor relationships, ensuring LSDB synchronization."

E (Correct):

"All routers within the same OSPF or IS-IS area have identical link-state databases after full synchronization."

Incorrect options:

A: Link-state protocols exchange only link-state information, not full routing tables (that’s distance-vector behavior).

D: Sequence numbers are incremented by the originator when generating LSAs, not by intermediate routers during flooding.

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Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — Area Border Routers (ABRs) Section:

“An ABR is a router connected to both area 0 and at least one non-backbone area, responsible for exchanging routing information between areas.”

ABRs serve as gateways between the backbone area (area 0) and non-backbone areas.

Summarization is optional on ABRs, not mandatory.

Thus, the correct answer is C.