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

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.

Comprehensive and Detailed Explanation From Exact Extract:

According toNokia 7750 SR OS OSPF Guide — OSPF Packet Transmission Section:

“OSPF is encapsulated directly over IP using protocol number 89. It does not use TCP or UDP.”

TCP (Protocol 6) → Incorrect.

UDP (Protocol 17) → Incorrect.

OSPF operates directly at IP layer using protocol number 89.

Thus, the correct answer isD.

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — Route Summarization Section:

“Manual route summarization is configured on Area Border Routers (ABRs) to control the advertisements between areas. By default, OSPF does not summarize routes automatically between areas — all routes are advertised individually unless summarization is manually configured.”

Summarization is always optional.

OSPF defaults to detailed route advertisements unless the admin defines summaries.

Thus, correct answer isD.