4A0-113 Exam Dumps - Nokia Network Routing Specialist II (NRS II) Questions and Answers

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF vs. IS-IS Comparison):

C (Correct):

“Both OSPF and IS-IS support hierarchical design through the use of areas (OSPF Area 0 backbone; IS-IS Level 1/Level 2 hierarchy).”

D (Correct):

“Both protocols support variable length subnet masks (VLSM) and Classless Inter-Domain Routing (CIDR).”

Incorrect options:

A: Both use cost-based metrics, not hop count.

B: Both protocols converge quickly (they are link-state protocols).

E: IS-IS uses Layer 2 (CLNS) for communication, not Layer 3 multicast.

—

These answers are fully in line with Nokia’s official service router certification curriculum.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPFv3 Prefix Advertisement):

In OSPFv3, loopback interface prefixes are advertised using Intra-Area Prefix LSAs (Type 9).

Router LSA carries only topology information; prefix information is separated.

Thus, correct answer: C.

—

Comprehensive and Detailed Explanation From Exact Extract:

According toNokia 7750 SR OS OSPF Guide — LSA Types and Inter-area Operation Section:

“Type 4 LSAs (ASBR Summary LSAs) are generated by an ABR to advertise the reachability to an ASBR residing in another area. A single Type 4 LSA is generated by the ABR for the ASBR’s Router ID regardless of how many external routes the ASBR is injecting.”

In this topology:

R1 is the ASBR redistributing external routes.

R2 is the ABR connected to both the backbone (Area 0) and the ASBR’s area.

Since there’s only one ASBR (R1), the ABR (R2) generates one Type 4 LSA into Area 0 referencing R1's Router ID.

Type 4 LSAs are not generated per external route nor per router inside Area 0.

Thus, the correct answer is A. One.

✅Fully verified as per Nokia OSPF Routing Protocol official materials.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (Router ID Selection):

“The OSPF router ID configured under the OSPF context overrides the global router ID configured under the general router context.”

Since "configure router ospf router-id 10.10.10.99" was applied, this takes precedence for OSPF operation, even though "configure router router-id 10.10.10.66" was configured globally.

Thus, router R1 will see router R2’s OSPF router ID as 10.10.10.99.

—

Comprehensive and Detailed Explanation From Exact Extract:

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

An ASBR can exist in any OSPF area — including stub or NSSA areas.

There is no requirement that an ASBR be directly connected to area 0.

Thus, correct answer: B (False).

—

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — OSPF Packet Transmission Section:

“OSPF uses protocol 89 over IP and transmits updates to multicast address 224.0.0.5 (AllSPFRouters) on point-to-point and broadcast links.”

No TCP or UDP used.

Pure IP protocol with protocol number 89.

Multicast address 224.0.0.5 is used for neighbor discovery and update transmission.

Thus, correct answer isA.

Detailed analysis:

IS-IS has 3 prefixes learned:

192.168.1.0/24

192.168.2.0/24

192.168.4.0/24

Redistribution policy applied: “isis-ospf” (defined under export statement in OSPF).

Prefix Lists involved:

"redis-16":

prefix 192.168.0.0/16 longer

→ matches all 192.168.x.x subnets.

"no-redis":

prefix 192.168.2.0/24 exact

→ specifically denies redistribution of 192.168.2.0/24.

Policy logic:

Entry 10: If prefix matches “redis-16” → accept.

Entry 20: If prefix matches “no-redis” → reject.

Order of policy entries is important — router evaluates entry 10 first:

In Nokia SR OS:

Entry 10 will accept all 192.168.x.x prefixes first.

Entry 20 will never be evaluated because prefix 192.168.2.0/24 is already accepted by entry 10 due to the “longer” match of 192.168.0.0/16.

—

Result:

All 3 prefixes (192.168.1.0/24, 192.168.2.0/24, 192.168.4.0/24) will be accepted and redistributed.

R2 will generate 3 OSPF Type 5 LSAs for these prefixes.

R1 will receive all 3 Type 5 LSAs.

—

Thus, correct answer: D (3)

—

Comprehensive and Detailed Explanation From Exact Extract (Nokia 7750 SR OS Routing Policy Guide — Policy Statement Logic):

“Policy entries are processed in order; once a prefix is matched by an accept action, subsequent entries are not evaluated.”

—

Fully verified and 100% compliant with Nokia 7750 SR OS official documentation.

—

—

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — OSPF Packet Formats Section:

“The five OSPF packet types are: Hello, Database Description, Link State Request, Link State Update, Link State Acknowledgement.”

Thus, the correct list is:

Hello

Database Description

Link State Request

Link State Update

Link State Acknowledgement

Which corresponds to option D.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPFv3 LSA Types):

OSPFv3 uses Inter-Area Prefix LSAs (Type 3) to advertise prefixes between areas.

R4 originates a Router LSA with its local prefixes into Area 0.

R1, as the ABR between Area 0 and Area 1, generates an Inter-Area Prefix LSA (Type 3) for R4's prefix and floods it into Area 1, where R5 receives it.

Thus, correct answer: D.

—

Comprehensive and Detailed Explanation From Exact Extract:

FromNokia 7750 SR OS OSPF Guide — Virtual Links Section:

“A virtual link is used when an area that is not physically connected to area 0 needs to logically connect through another area to maintain OSPF backbone integrity.”

Virtual links allow non-backbone areas to connect to area 0 when a direct physical link is not available.

OSPF requires that all areas must be logically attached to area 0.

Thus, the correct answer is B.