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

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Comprehensive and Detailed Explanation From Exact Extract:

According to Nokia 7750 SR OS Routing Protocols Guide (Static Routing section, Chapter 5: Configuring Static Routes):

“A static route is configured by specifying the destination prefix and the next-hop IP address. The next-hop IP address must be reachable via a directly connected interface.”

In this scenario:

The network R1 wants to reach is 139.120.121.0/24 (behind R2).

R1 can reach R2 directly via IP 138.120.199.2 (the next-hop).

Therefore, the correct static route configuration on R1 is:

configure router static-route 139.120.121.0/24 next-hop 138.120.199.2

Explanation of incorrect options:

Option B: Next-hop 138.120.199.1 is R1 itself, invalid.

Option C: Configures a route to R2's interface, not the target subnet.

Option D: Next-hop 139.120.121.2 is unreachable from R1 directly.

This command structure strictly follows the syntax and logic described in Nokia’s SR OS: Static Routing Configuration Guide and is aligned with standard Nokia service router configuration practices.

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:

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.