- The Exam at a Glance
- Registration, Fee and Retake Facts
- The Five Preparation Modules in One Pass
- Traffic Classification: What to Memorize
- Queues and Policers: Mental Models
- Hierarchical Bandwidth and Remarking
- How the Questions Behave
- SRA Credit, Validity and the 2026/27 Update
- Scheduling the Modules Across Your Prep
- Frequently Asked Questions
- 4A0-107 is Nokia's 40-question, multiple-choice written exam with 90 minutes of testing, delivered through Pearson VUE for USD 125.
- Scope follows five unweighted modules: Introduction to QoS, Traffic Classification, Queues and Policers, Hierarchical Bandwidth Allocation, and Marking and...
- Passing 4A0-107 earns Service Routing Architect credit but does not award SRA by itself; the seven-hour practical lab is separate.
- No official passing percentage was verified, so aim for command of every module rather than a target score.
The Exam at a Glance
This page condenses what you need to keep in your head on exam day for Nokia's Quality of Service written exam, 4A0-107. It is a reference sheet, not a tutorial. If you need the full learning path, start with the 4A0-107 Study Guide 2026: How to Pass on Your First Attempt and come back here for final review.
| Item | Fact |
|---|---|
| Exam code | 4A0-107 (Nokia Quality of Service) |
| Vendor | Nokia (formerly Alcatel-Lucent) |
| Delivery | Pearson VUE, proctored online or at a test center |
| Fee | USD 125 |
| Format | 40 multiple-choice written questions, English |
| Testing time | 90 minutes |
| Appointment length | 110 minutes, including a 20-minute introductory survey |
| Prerequisites | None mandatory for the exam |
| Passing percentage | No official figure verified in reviewed public sources |
Note the arithmetic of the clock: 90 minutes across 40 questions leaves a little over two minutes per question on average. That is generous for recall items, but scenario questions that require you to trace a packet through classification, queueing and remarking will consume more. Budget accordingly, and flag and revisit rather than stalling.
Registration, Fee and Retake Facts
The mechanics are simple, but candidates still trip over them. Keep these straight:
- Booking: Pearson VUE handles scheduling. You choose online proctoring or a test center.
- Appointment versus exam time: The 110-minute appointment includes a 20-minute introductory survey. Only 90 minutes are testing time.
- Fee: USD 125. For a deeper breakdown of what surrounds that number, see 4A0-107 Certification Cost 2026: Complete Pricing Breakdown.
- Retakes: Written-exam retakes have no mandatory waiting period and no attempt limit. Each retake is still a new sitting, so treat a first attempt as real rather than a free trial.
- Prerequisites: None are mandatory to sit the exam. Training is optional, and the course prerequisites are preparation guidance rather than gatekeeping. The details live in 4A0-107 Requirements 2026: Eligibility, Prerequisites & How to Qualify.
The Five Preparation Modules in One Pass
The scope source is Nokia's Quality of Service course (3FL30639AAAAZZZZA), and the exam page explicitly points candidates to that course's objectives and modules. The five headings below are unweighted preparation modules. They do not establish exhaustive exam coverage, official percentage allocations, or an official domain count, so do not assume any one module is "worth" a fixed share of questions. For a longer treatment, read 4A0-107 Exam Domains 2026: Complete Guide to All 5 Content Areas.
Introduction to QoS
The vocabulary and reasoning that every later module builds on.
- Why QoS exists: shared resources, contention, and differentiated treatment
- The idea of treating traffic by class rather than by individual flow
- Where QoS decisions are made along a forwarding path
Traffic Classification
How traffic is identified and mapped to a forwarding class.
- Match criteria and how they drive classification
- The relationship between classification and the treatment that follows
- Trust boundaries: what you accept from the sender versus what you rewrite
Queues and Policers
The core mechanics of buffering, scheduling and rate enforcement.
- How queues hold and release traffic
- How policers enforce a rate by dropping or reclassifying, as opposed to delaying
- The behavioral difference between shaping-style queuing and policing
Hierarchical Bandwidth Allocation
Sharing bandwidth across levels so aggregates and individual queues both get fair treatment.
- Parent and child relationships among schedulers
- How committed and excess bandwidth are distributed
- Why hierarchy matters when many subscribers or services share one port
Marking and Remarking
Changing the QoS values carried in packets so downstream devices treat them correctly.
- When to mark, when to remark, and when to leave values untouched
- How ingress and egress behavior differ
- Consistency of treatment across a multi-hop network
Traffic Classification: What to Memorize
Classification questions reward a precise mental pipeline. Burn this sequence in: a packet arrives, it is matched, it is assigned to a class, and that class determines which queue and which rate treatment it receives. Nearly every wrong answer in this area comes from confusing the stage at which a decision is made.
Checks to run on every classification question
- Identify where in the path the question is set: ingress or egress.
- Identify what the packet carries on arrival, and whether the device trusts it.
- Determine which match criterion actually applies when more than one could.
- Trace the resulting class forward to its queue.
Queues and Policers: Mental Models
This is the module where candidates most often blur two ideas, so separate them cleanly.
| Concept | What it does to excess traffic | Effect on timing |
|---|---|---|
| Queue with scheduling | Holds traffic in a buffer and releases it according to scheduling rules; drops occur when buffering is exhausted | Adds delay while traffic waits |
| Policer | Compares traffic to a configured rate and acts on the excess, typically by dropping or treating it differently | No waiting; the decision is immediate |
When a question asks which tool suits a scenario, the discriminator is almost always whether the requirement is to smooth traffic (queuing and scheduling) or to enforce a contract (policing). Read the scenario for words that signal contract enforcement, such as a hard limit or an excess that must not pass, versus words that signal smoothing or fair sharing.
Fast recall prompts
- A queue's value is in how it is serviced relative to other queues, not just its size.
- A policer cannot make traffic wait, so a scenario that needs traffic delayed rather than discarded does not describe policing.
- Rate parameters are meaningful only in context: ask what the rate is applied to, a single queue, a class, or an aggregate.
Hierarchical Bandwidth Allocation and Remarking
Hierarchical questions are typically short word problems about sharing. Draw the tree on your scratch surface the moment you read the stem: a port or aggregate at the top, services or subscribers beneath, queues at the leaves. Then ask what each level guarantees and what each level caps. Candidates who skip the sketch tend to apply a parent's limit to the wrong child.
Key Takeaway
For hierarchy questions, always resolve the bottom of the tree first (what does this queue want?), then check each parent upward (what does this level permit?). The effective result is bounded by the most restrictive level the traffic must pass through.
Marking versus remarking
Marking sets values on traffic; remarking changes values that are already present. The exam-relevant skill is deciding when a value should be overwritten. Typical reasoning: values received from an untrusted source should be rewritten to match local policy, while values from a trusted source can be preserved so treatment stays consistent end to end. Expect scenarios where the wrong answer preserves a value that should have been rewritten, or rewrites one that should have been preserved.
How the Questions Behave
All 40 questions are multiple choice in English. Based on the scope above, expect a mix of three types:
- Definition and recall: terms, purposes, and which module a concept belongs to.
- Behavioral reasoning: given a configuration or situation, what happens to a packet or a flow.
- Configuration reading: because current course cases and labs use MD-CLI, be comfortable reading MD-CLI-style configuration and deducing intent from it.
Nokia publishes a linked practice document, Practice Exam Questions for Nokia Quality of Service (4A0-107), copyright 2024, document code (June) CID202017. Use it to calibrate wording and format, but treat it as a sample of style rather than a promise of what appears on your exam. For a candid read on difficulty, see How Hard Is the 4A0-107 Exam? Complete Difficulty Guide 2026.
SRA Credit, Validity and the 2026/27 Update
Passing 4A0-107 earns Service Routing Architect (SRA) credit, but it does not award SRA on its own. The SRA path also includes other written requirements and the seven-hour practical lab.
- Credential validity: SRC certifications are valid for three years, with recertification available before termination six months after expiry.
- Renewal use: 4A0-107 is an accepted renewal option for NRS I, NRS II and SRA.
- Careful reading: These are credential-maintenance rules. They do not establish a separate expiry date for the exam credit itself.
The 2026/27 program update
Nokia's program update, "Important updates are coming to the Service Routing Certification (SRC) Program in 2026/27" (September 8, 2026), reduces SRA written requirements from eight to five and retains 4A0-107. The practical lab is unchanged. In short, this exam stays on the SRA path. Check Nokia's pages directly before booking, since program details can change, and see 4A0-107 Exam Dates 2026: Testing Windows, Deadlines & Scheduling for scheduling context.
Why employers care
QoS knowledge matters wherever service providers and large enterprises run Nokia service routing and must guarantee differentiated treatment for voice, video, business services and best-effort traffic. Roles that touch network design, service delivery and operations tend to value it. For role and pay context, see 4A0-107 Jobs and 4A0-107 Salary Guide 2026: Complete Earnings Analysis, and for the bigger picture, Is the 4A0-107 Certification Worth It? Complete ROI Analysis 2026.
Scheduling the Modules Across Your Prep
The modules build on each other, so order matters more than hours. This is a suggested sequence, not an official one:
Introduction to QoS and Traffic Classification
- Lock in vocabulary and the packet-to-class pipeline before anything else
- Practice the ingress-versus-egress question every time
Queues and Policers
- Drill the queue-versus-policer distinction until it is automatic
- Read MD-CLI snippets and state what each line accomplishes
Hierarchical Bandwidth Allocation
- Sketch a tree for every scenario
- Work upward from leaf queues through each parent
Marking and Remarking, then full review
- Decide trust and rewrite behavior for each scenario
- Finish with timed sets from the 4A0-107 practice tests and revisit weak modules
Hierarchy comes after queues because it is a way of organizing queues and schedulers, and remarking comes last because it ties classification and treatment together across the whole path. If you want structured drilling by module, the practice question bank on the main site is built for exactly that kind of final pass. For orientation on what the code and certification represent, the explainers What Is 4A0-107? and 4A0-107 Certification cover the basics, and 4A0-107 Training covers course options.
Frequently Asked Questions
The exam has 40 multiple-choice written questions in English, with 90 minutes of testing. The appointment is 110 minutes because it includes a 20-minute introductory survey.
The fee is USD 125, and the exam is delivered through Pearson VUE, either online with a proctor or at a test center.
No. It earns SRA credit only. The SRA path also involves other written requirements and a separate seven-hour practical lab, which is a different activity from this 90-minute written exam.
No official passing percentage was verified in the public sources reviewed, so no specific cut score can be stated. Prepare to understand all five modules rather than aiming at an assumed threshold.
Written-exam retakes have no mandatory waiting period and no attempt limit. Each attempt is a new sitting with its own fee, so it is still worth preparing properly the first time.