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

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — OSPF Timers Section:

“The default OSPF Hello interval is 10 seconds, and the default Dead interval is four times the Hello interval (40 seconds).”

Thus:

Hello interval = 10 seconds

Dead interval = 40 seconds

This configuration ensures stability in adjacency monitoring.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Operation – Adjacency and Link Failures):

"If connectivity is lost (e.g. link failure between switches), OSPF adjacencies between routers timeout due to absence of Hello packets. When adjacency is lost, LSDB recalculation and LSA flooding occur to inform all routers of the new topology."

The physical interface may remain up (because directly connected interfaces to switches remain electrically active), but no Hello packets are exchanged → triggers adjacency loss → triggers convergence.

LSAs are not sent between routers to notify about link failures directly — they are generated after adjacency loss.

Thus, option A is fully correct.

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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