100+ Free Nokia MPLS Practice Questions

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What does FEC stand for in MPLS, and what role does it play?

Forward Error Correction; corrects bit errors in the label header

Fast Ethernet Channel; bonds physical links

Final Egress Code; signals egress LER identity

Forwarding Equivalence Class; group of packets treated identically by the LSP

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Key Facts: Nokia MPLS Exam

Exam Questions

Nokia 4A0-103 exam profile

90 min

Exam Duration

Nokia 4A0-103 exam profile

70%

Passing Score

Nokia SRC scoring policy

$125

Exam Fee (USD)

Pearson VUE Nokia pricing

Pearson VUE

Test Provider

Nokia SRC delivery partner

3 years

Credential Validity

Nokia SRC recertification policy

The Nokia MPLS exam (4A0-103) is a 40-question, 90-minute multiple-choice test delivered through Pearson VUE for $125 USD with a 70% passing score. Candidates are tested on MPLS architecture (RFC 3031), the 32-bit shim header (RFC 3032), LDP (RFC 5036) and RSVP-TE (RFC 3209) signaling, CSPF traffic engineering with admin-group, bandwidth, and SRLG constraints, RFC 4090 Fast Reroute (one-to-one and facility backup), and Nokia 7750 SR OS MPLS configuration and troubleshooting. The credential is part of the Nokia Service Routing Certification program and is valid for three years.

Sample Nokia MPLS Practice Questions

Try these sample questions to test your Nokia MPLS exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which RFC defines the core MPLS architecture that the Nokia 4A0-103 exam is built on?

A.RFC 2547

B.RFC 3031

C.RFC 4364

D.RFC 5036

Explanation: RFC 3031 'Multiprotocol Label Switching Architecture' defines the foundational MPLS forwarding model: FECs, LSRs/LERs, label stack semantics, and the separation of control and forwarding planes. It is the base specification referenced by all Nokia 7750 SR MPLS implementations.

2How many bits are in the MPLS shim header defined by RFC 3032?

A.20 bits

B.24 bits

C.32 bits

D.64 bits

Explanation: The MPLS label stack entry defined in RFC 3032 is exactly 32 bits long: 20 bits of label, 3 bits of Traffic Class (formerly EXP), 1 bit Bottom-of-Stack (S), and 8 bits of TTL. Multiple 32-bit shims can be stacked to nest services.

3In the MPLS shim header, which field carries the QoS marking that was historically called EXP?

A.Label

B.Traffic Class (TC)

C.S

D.TTL

Explanation: RFC 5462 renamed the 3-bit EXP field to Traffic Class (TC). It is still the same 3 bits in the shim header used by E-LSPs to carry the per-hop-behavior class.

4What is the purpose of the S bit in an MPLS label stack entry?

A.It signals that the packet should be policed at this hop

B.It indicates this is the bottom-most label in the stack

C.It marks the label as a service label rather than a transport label

D.It carries an explicit-null indication

Explanation: The 1-bit S (Bottom-of-Stack) field is set to 1 in the last (innermost) label entry and 0 in all entries above it. The forwarding plane uses S=1 to know it has reached the IP/Ethernet payload after popping.

5Which MPLS reserved label tells the upstream LSR to perform Penultimate Hop Popping (PHP) and is the default Nokia SR OS behavior?

A.0 (IPv4 Explicit Null)

B.1 (Router Alert)

C.2 (IPv6 Explicit Null)

D.3 (Implicit Null)

Explanation: Label value 3 is Implicit Null. When an egress LER signals label 3 to its upstream neighbor, the penultimate hop pops the label before forwarding so the egress receives an unlabeled packet, saving a lookup. This is the default Nokia SR OS behavior.

6In MPLS terminology, which device performs label imposition (push) and label disposition (pop) at the edge of the MPLS network?

A.LSR (Label Switching Router)

B.LER (Label Edge Router)

C.P (Provider) router only

D.Route Reflector

Explanation: An LER sits at the edge of the MPLS domain. The ingress LER classifies the packet to a FEC and pushes the label stack; the egress LER pops labels and forwards based on the original IP/Ethernet header. Transit nodes are LSRs that swap labels.

7What does FEC stand for in MPLS, and what role does it play?

A.Forward Error Correction; corrects bit errors in the label header

B.Forwarding Equivalence Class; group of packets treated identically by the LSP

C.Fast Ethernet Channel; bonds physical links

D.Final Egress Code; signals egress LER identity

Explanation: A Forwarding Equivalence Class is a set of packets that an ingress LER decides to forward in the same way - the same next hop, the same QoS, the same LSP. The label that the ingress pushes maps directly to a FEC.

8On a transit Nokia 7750 SR, which data structure is consulted by the forwarding ASIC when an MPLS-labeled packet arrives?

A.RIB (Routing Information Base)

B.FIB (IP Forwarding Information Base)

C.LFIB (Label Forwarding Information Base)

D.NLRI table

Explanation: The LFIB is the label-indexed forwarding table built from LDP/RSVP-TE label bindings. A transit LSR uses the incoming label as the lookup key, retrieves the NHLFE, performs the swap, and forwards out the next-hop interface.

9Which structure represents the action taken on a labeled packet for a given outgoing label and next hop on Nokia SR OS?

A.FTN (FEC-to-NHLFE)

B.ILM (Incoming Label Map)

C.NHLFE (Next Hop Label Forwarding Entry)

D.RIB-out

Explanation: An NHLFE describes the per-next-hop action on a labeled packet: the outgoing interface, the next-hop link-layer info, and the label operation (swap to label X, push label Y, or pop). ILM and FTN entries point at NHLFEs.

10Which sequence of label operations is performed on a packet that traverses an MPLS LSP from ingress LER through one transit LSR to egress LER (with PHP enabled)?

A.push, push, pop

B.push, swap, pop (performed by penultimate router)

C.swap, swap, swap

D.pop, swap, push

Explanation: The ingress LER pushes the transport label, the transit LSR swaps it for the next-hop label, and with PHP the penultimate router pops the label before delivering an unlabeled packet to the egress LER for IP lookup.

About the Nokia MPLS Exam

The Nokia 4A0-103 MPLS exam is a Service Routing Certification (SRC) credential that validates intermediate-level knowledge of Multiprotocol Label Switching architecture, label distribution with LDP and RSVP-TE, traffic engineering with CSPF and constrained paths, MPLS resiliency with Fast Reroute and Make-Before-Break, and the implementation of these features on Nokia 7750 SR routers running SR OS. It targets engineers who design, deploy, and operate MPLS networks for service-provider transport and VPN services.

Assessment

40 multiple-choice questions covering MPLS fundamentals, label distribution (LDP, RSVP-TE), traffic engineering and resiliency (CSPF, FRR, MBB), and Nokia SR OS MPLS configuration on the 7750 SR

Time Limit

90 minutes

Passing Score

70%

Exam Fee

$125 (Nokia / Pearson VUE)

Nokia MPLS Exam Content Outline

25%

MPLS Fundamentals

MPLS architecture (RFC 3031), 32-bit shim header (RFC 3032: 20-bit Label, 3-bit TC, 1-bit S, 8-bit TTL), label stack, LSR/LER roles, FEC, push/swap/pop, PHP with implicit-null label 3, explicit-null labels 0 and 2, LFIB, and NHLFE.

30%

Label Distribution Protocols

LDP (RFC 5036, UDP 646 Hellos, TCP 646 session, downstream-unsolicited default, liberal retention, ordered vs independent control, T-LDP for pseudowires), LDP-IGP Sync (RFC 5443), LDP graceful restart (RFC 3478), session protection, and RSVP-TE (RFC 3209) with PATH, RESV, PathErr, ResvErr, PathTear, ResvTear, and Hello messages.

25%

Traffic Engineering and Resiliency

CSPF with bandwidth, admin-group/affinity, hop-count and SRLG constraints; strict and loose ERO; RRO; Make-Before-Break with Shared Explicit reservation style; 8-priority setup/hold preemption; RFC 4090 Fast Reroute (one-to-one detour and facility bypass, link vs node protection); BFD for MPLS; LSP Ping and LSP Trace (RFC 4379).

20%

MPLS on Nokia SR OS

Configuration under configure router mpls / ldp / rsvp on the Nokia 7750 SR, MPLS path and LSP objects, mesh-p2p and one-hop-p2p LSP templates, PrimaryActive/SecondaryActive/Standby LSP states, MPLS-over-GRE and MPLS-over-UDP encapsulation, propagate-ttl uniform mode, and show router mpls / ldp / rsvp commands for verification and troubleshooting.

How to Pass the Nokia MPLS Exam

What You Need to Know

Passing score: 70%
Assessment: 40 multiple-choice questions covering MPLS fundamentals, label distribution (LDP, RSVP-TE), traffic engineering and resiliency (CSPF, FRR, MBB), and Nokia SR OS MPLS configuration on the 7750 SR
Time limit: 90 minutes
Exam fee: $125

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

Nokia MPLS Study Tips from Top Performers

1Memorize the MPLS shim layout (20-bit Label + 3-bit TC + 1-bit S + 8-bit TTL = 32 bits) and the reserved labels (0 = IPv4 explicit-null, 1 = router alert, 2 = IPv6 explicit-null, 3 = implicit-null/PHP, 7 = ELI, 13 = GAL).

2Drill the LDP transport split: UDP 646 for multicast Hello discovery and TCP 646 for the actual LDP session - it is a near-guaranteed exam item.

3Lock in the RSVP-TE message set in order: PATH (with Sender_Tspec, ERO, Session_Attribute), RESV (with Flowspec and Label), and the PathTear / ResvTear / PathErr / ResvErr / Hello supporting messages.

4Build a clear mental model of FRR variants: one-to-one (detour LSP per protected LSP) vs facility (single bypass tunnel for many LSPs), and link (NHOP) vs node (NNHOP) protection.

5Be fluent in CSPF constraints: bandwidth, admin-group/affinity (32-bit bitmap with include-any/include-all/exclude), hop-limit, and SRLG, plus how strict vs loose ERO hops affect path computation.

6Practice the Nokia LSP state machine - PrimaryActive vs SecondaryActive vs Standby - and how 'adaptive' enables Make-Before-Break for planned changes.

7Memorize the four key Nokia troubleshooting commands: show router mpls lsp (and path detail), show router ldp peer / bindings, show router rsvp session / interface, and show router mpls forwarding (LFIB).

Frequently Asked Questions

What is on the Nokia 4A0-103 MPLS exam?

The Nokia 4A0-103 exam tests MPLS architecture (RFC 3031), the 32-bit MPLS shim (RFC 3032), label distribution with LDP (RFC 5036) and RSVP-TE (RFC 3209), traffic engineering with CSPF, ERO, RRO and admin-group/SRLG constraints, MPLS resiliency including RFC 4090 Fast Reroute and Make-Before-Break, MPLS OAM with LSP Ping/Trace (RFC 4379), and the implementation of MPLS on Nokia 7750 SR routers running SR OS classic CLI. It is part of the Nokia Service Routing Certification (SRC) program.

How long is the Nokia MPLS exam and how many questions does it have?

The 4A0-103 exam contains 40 multiple-choice questions with a 90-minute time limit. Nokia recommends pacing at roughly 2 minutes per question and saving a few minutes at the end to flag and review uncertain answers.

What is the passing score for Nokia 4A0-103?

Nokia requires a 70% score (28 of 40 correct) to pass the MPLS exam. Aim for 85% or higher in practice exams - service-provider topics like RSVP-TE Session_Attribute, FRR variants, and Nokia LSP states are common stumbling blocks.

How much does the Nokia 4A0-103 MPLS exam cost?

The 4A0-103 exam fee is $125 USD per attempt, paid to Pearson VUE at registration. Optional Nokia self-paced or instructor-led MPLS training is sold separately and is not required to sit the exam.

How long is the Nokia MPLS credential valid?

Nokia SRC credentials, including the MPLS exam, are valid for three years. To stay current, candidates must pass any current Nokia SRC exam (4A0-103, NRS II, or higher-level exams) within the three-year window or recertify by retaking 4A0-103.

Are there prerequisites for 4A0-103?

There are no formal prerequisites for 4A0-103, but candidates are expected to be comfortable with TCP/IP, IPv4 addressing, OSPF or IS-IS, and BGP basics. Nokia recommends, but does not require, NRS I (4A0-100) and the self-paced or instructor-led Nokia MPLS course before sitting the exam.

Where do I take the Nokia MPLS exam?

The 4A0-103 exam is delivered by Pearson VUE either at a Pearson VUE test center or via OnVUE online proctoring, where available. Schedule through pearsonvue.com/us/en/nokia.html with your Nokia candidate profile.

100+ Free Nokia MPLS Practice Questions

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