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

Comprehensive and Detailed Explanation From Exact Extract:

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

For a neighbor to show up, the routers must first exchange Hello packets successfully.

Area ID mismatch (C), interface down (B), or no Hello received (D) are all valid reasons neighbors won't appear.

However, OSPF Database Description (DBD) packets are exchanged only after neighbor adjacency is established. If no neighbor is detected, the DBD packet exchange has not yet started.

Thus, correct answer: A.

—

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Packet Headers):

“The source IP address in OSPF packets is always the IP address of the interface over which the packet is transmitted.”

224.0.0.5 and 224.0.0.6 are destination multicast addresses, not source addresses.

Thus, correct answer: C.

—

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — LSA Types and Area Border Routers:

“Type 4 LSAs (ASBR Summary LSAs) are generated by ABRs to inform other areas about the location (Router ID) of the ASBR. Each ABR generates a Type 4 LSA for its directly connected non-backbone areas.”

R3 generates Type 4 LSA into Area 0.

R6 generates Type 4 LSA into Area 2.

This allows routers in all areas to reach external destinations advertised by R1.

Comprehensive and Detailed Explanation From Exact Extract (Nokia 7750 SR OS Routing Protocols Guide — OSPF Inter-Area Routing):

Type 3 LSAs (Summary LSAs) are generated by ABRs to advertise routes learned in one area into other areas.

Type 1 = Router LSAs (intra-area only).

Type 4 = ASBR Summary LSAs (used for ASBR reachability).

Type 7 = NSSA external routes.

Thus, correct answer: B.

—