Nokia Updated 4A0-113 Exam Questions and Answers by stephen

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF NSSA Behavior):

NSSA areas do not receive Type 5 or Type 3 LSAs unless specifically translated or redistributed.

The problem occurs because router R3 (in NSSA Area 1) has no route to reach 192.168.3.1 unless a default route is injected.

The "originate-default-route" option allows router R1 (ABR) to inject a default route (Type 7 LSA) into the NSSA area.

Thus, correct answer: A.

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Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Features Summary and Extensions):

C (Correct):

"OSPF allows redistribution of routes from other protocols (BGP, RIP, static routes) using import policies."

D (Correct):

"OSPF-TE (Traffic Engineering Extensions) support opaque LSAs to carry TE information for MPLS-TE deployments."

Incorrect options:

A: Fast reroute (FRR) is an MPLS feature, not native to OSPF.

B: OSPF does not prioritize control traffic natively.

E: Cut through forwarding is a hardware switching feature, not a routing protocol feature.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Route Policies):

“Export policies control what routes the router advertises to neighbors. Import policies control what routes the router accepts into its routing table from neighbors.”

The goal is to reject the OSPF route learned from R2.

Since R1 is receiving routes via OSPF, an IMPORT policy is required.

Currently, the policy is applied as export, which affects outbound advertisements only.

Thus, correct answer is C

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (Route Preferences – Default Administrative Distances):

IS-IS Level 1 internal preference: 18

OSPF external (Type 5) preference: 150

R3 will have both routes:

B (Correct): IS-IS Level 1 internal route received directly from IS-IS (lower preference value 18).

D (Correct): OSPF external route received via redistribution (higher preference value 150).

Since IS-IS internal has better preference, it will be installed, but both exist as valid route types.

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