- What You Are Actually Preparing For
- Exam Format, Fee and Registration Mechanics
- The Six-Module Map and How to Read It
- Modules 1 and 3: Layered Models and Ethernet
- Module 2: SR OS and the Command Line
- Module 4: The Internet Layer
- Module 5: Static Routes, OSPF and BGP
- Module 6: VPNs, MPLS and Service Types
- Sequencing Your Weeks Around the Modules
- Watch the 2027 Exam Transition
- Where This Credential Fits in a Career
- Frequently Asked Questions
- NRS I requires one exam: 4A0-100 IP Networks and Services Fundamentals, with 40 multiple-choice questions in 90 minutes.
- The published exam fee is USD 125, separate from any Nokia training course price.
- Six modules, 28 subtopics, form the issuer-designated preparation outline; they are not a weighted blueprint.
- No mandatory exam prerequisite is listed, but SR OS CLI familiarity makes the services material far easier.
What You Are Actually Preparing For
Nokia Network Routing Specialist I is the entry point of Nokia's routing certification path. It validates that you understand how IP networks and the services built on them work, and that you can place Nokia's service-router products in that picture. The certification is built around a single mandatory exam, 4A0-100 IP Networks and Services Fundamentals. If you are still orienting yourself, the explainers on what NRS I certification is and what NRS I stands for cover the basics; this guide assumes you have decided to sit the exam and want a plan.
One point of discipline before going further: "NRS I" here means the Nokia credential only. Other certifications share similar abbreviations, and their fees, bodies and exam structures have nothing to do with this one. Every figure in this article comes from Nokia's published exam, certification and course pages, reviewed in October 2026.
Exam Format, Fee and Registration Mechanics
Knowing the logistics removes avoidable stress, so settle them first.
| Item | What Nokia publishes |
|---|---|
| Exam | 4A0-100 IP Networks and Services Fundamentals |
| Question style | Multiple choice |
| Number of questions | 40 |
| Exam duration | 90 minutes |
| Appointment length | 110 minutes, including a 20-minute introductory survey |
| Exam fee | USD 125 |
| Mandatory exam prerequisite | None listed |
| Training | Priced separately from the exam |
Two details trip people up. First, the 110-minute appointment is not the exam time. The first 20 minutes are an introductory survey, and the timed portion is 90 minutes. At 40 questions, that is a little over two minutes per item, which is generous for multiple choice but not for questions that require you to work through a subnet calculation or trace a forwarding decision. Second, training costs and exam costs are different line items. A course purchase does not change the exam fee. For a fuller breakdown of what you will spend, see the NRS I certification cost guide, and for eligibility questions see the NRS I requirements article.
Nokia does not publish a pass threshold, scored versus unscored split or pass rate that we can cite here, so treat any specific number you see quoted elsewhere with suspicion. The NRS I passing score and pass rate pages explain what is and is not known. The practical consequence is simple: prepare for mastery of all six modules rather than aiming to scrape by on a favorite few.
The Six-Module Map and How to Read It
Nokia presents six modules and 28 subtopics as the preparation outline for this exam. Nokia's exam page directs candidates to the course objectives and modules. The outline is not presented as a weighted blueprint or as an exhaustive list of everything that can appear. That has two implications for your study.
- Do not allocate time by guessed percentages. No official weights exist in the source material, so a plan that says "spend 30 percent on routing" is invented. Spread effort across all six modules and then adjust based on your own practice results.
- Treat the outline as a floor, not a ceiling. Because the list is not asserted to be exhaustive, read adjacent material in each module rather than memorizing only the named subtopics.
The six modules, in Nokia's order, are Introduction to Networking and Services, Service Router Components and Command Line Interface, Ethernet, The Internet Layer, IP Routing Protocol Basics, and Services Overview. The NRS I exam domains guide goes deeper on each area; below is how I would approach them in practice.
Modules 1 and 3: Layered Models and Ethernet
Introduction to Networking and Services
This module sets the vocabulary everything else depends on. Expect questions that test whether you understand how data moves down and up a protocol stack, not just whether you can recite layer names.
- Protocol-layer models and what each layer is responsible for
- Encapsulating and decapsulating traffic as it crosses layers
- Separating control from forwarding, the idea that a router decides how to build its forwarding information separately from the act of moving packets
The control-versus-forwarding distinction deserves extra attention because it returns in later modules. When you reach static routes, OSPF and BGP, you are studying control-plane behavior. When you reach forwarding decisions and packet-header fields, you are studying the forwarding plane. Candidates who keep the two straight find the routing and services modules much less confusing.
Ethernet
Ethernet is a full module, not a warm-up. The subtopics reward precise understanding of how frames behave on a LAN.
- Access to shared media, and why contention matters
- Hub versus switch behavior, including what each device does with an incoming frame
- Link-layer addressing and how a frame is directed on a segment
- VLAN segmentation and how it splits broadcast domains
- Redundant Ethernet designs and the problem they must avoid
- Frame structure, including the fields a frame carries
A useful drill: for each device type, write one sentence describing what it does when a frame arrives and one sentence describing what it does when the destination is unknown. Multiple-choice distractors in this area usually exploit confusion between hub flooding, switch learning and broadcast handling.
Module 2: SR OS and the Command Line
This is the most Nokia-specific module, and the one where generic networking study will not carry you. It covers the service-router product range, the 7750 SR hardware, the router boot sequence, and operating and configuring SR OS.
Service Router Components and Command Line Interface
You need a working mental model of the platform and enough CLI fluency to recognize correct configuration.
- Where the service-router product family fits in a network, and what role the 7750 SR plays
- The major hardware components of the 7750 SR and what each contributes
- The router boot sequence, in order, and what is loaded or established at each stage
- Navigating and operating SR OS, and configuring service components
If you have no access to a lab, a free or virtualized environment is worth the effort. Even an hour of navigating the configuration hierarchy makes the Services Overview module far more concrete. For structured options, the NRS I training overview compares the paths available.
Module 4: The Internet Layer
This module carries the heaviest calculation burden and rewards repetition more than any other.
The Internet Layer
IPv4 fluency is non-negotiable. You should be able to work addressing problems quickly and by hand.
- IPv4 addressing, including how prefix length divides network and host portions
- Subnetting and summarizing routes, both splitting a block and aggregating several into one
- Layer 3 interfaces on the 7750 SR, tying addressing to the platform
- Forwarding decisions, including how a router chooses where to send a packet
- Packet-header fields and what each is used for
- Residential and small-business connectivity scenarios
Two skills deserve daily practice: finding the network address, broadcast address and usable range for an arbitrary prefix, and judging whether a set of contiguous prefixes can be summarized into a single route without covering addresses that do not belong. With 90 minutes for 40 questions you have time to calculate, but only if the arithmetic is automatic. Build speed with short, original drills rather than long sessions.
Module 5: Static Routes, OSPF and BGP
IP Routing Protocol Basics
This module contrasts manual and dynamic routing and introduces the two protocols at the center of Nokia's fundamentals curriculum.
- Static route configuration, and when static routing is the right tool
- OSPF fundamentals, the interior protocol used within a network
- An introduction to BGP, the protocol that connects independently managed networks
- Internet building blocks, how separate networks interconnect at scale
The key conceptual contrast is interior versus exterior routing. OSPF operates within an administrative domain, while BGP is how separately operated networks exchange reachability. Candidates often lose points by assuming BGP is simply "a bigger OSPF." Frame it instead by purpose: OSPF discovers and maintains paths inside one network, BGP expresses policy and reachability between networks. Also be ready to explain why a small network might use static routes while a growing one moves to a dynamic protocol.
Module 6: VPNs, MPLS and Service Types
The final module is where the credential's "Network Routing Specialist" identity shows. It introduces the service model that Nokia routers are built to deliver.
Services Overview
You must connect the transport layer (MPLS) to the customer-facing service layer (VPNs).
- VPN concepts and why providers offer them
- MPLS tunnel transport, the mechanism that carries service traffic across the provider network
- Distributing labels with LDP
- Elements of a VPN service, the components that combine to define one
- VPWS, VPLS and VPRN configuration, the three service types you need to distinguish
| Service | Study angle |
|---|---|
| VPWS | Know the point-to-point nature of this service and how it differs from a multipoint design. |
| VPLS | Know the multipoint, Ethernet-oriented behavior and how it contrasts with a routed service. |
| VPRN | Know the routed, Layer 3 nature of the service and how the customer relationship differs. |
Key Takeaway
Learn the services as a stack: MPLS provides tunnels, LDP distributes the labels that make those tunnels usable, and VPWS, VPLS or VPRN rides on top to deliver the customer service. If a question mixes layers, ask yourself which layer of this stack it is really about.
Sequencing Your Weeks Around the Modules
Generic scheduling advice is not very helpful here, so this plan is tied to the dependencies between modules. It assumes roughly six weeks and should be stretched if you are new to networking or compressed if you work with routers daily. Because the outline carries no official weights, the sequence follows prerequisite logic rather than percentages.
Models and Ethernet
- Work through encapsulation and the control-versus-forwarding split
- Cover hubs, switches, VLANs, redundancy and frame structure
Platform and CLI
- Study the 7750 SR hardware and the boot sequence
- Practice MD-CLI navigation in a lab if you can get one
The Internet Layer
- Daily subnetting and summarization drills
- Trace forwarding decisions and header fields by hand
Routing Protocols
- Static routes first, then OSPF, then the BGP introduction
- Write a one-paragraph "why this protocol" answer for each
Services and Review
- MPLS, LDP and the three VPN service types
- Full-length timed practice, then revisit your weakest module
Addressing gets two weeks because the arithmetic needs repetition and because routing questions in Module 5 assume you can read prefixes without effort. Services come last because they depend on everything before them. When you begin timed practice, use the NRS I practice tests to find your weak areas, then loop back to the relevant module. A one-page NRS I cheat sheet is useful for the final review, but build your own as you go, since writing it is part of learning it.
If you want a realistic sense of effort before committing to a timeline, the difficulty guide discusses what tends to challenge candidates most.
Watch the 2027 Exam Transition
The practical advice is to schedule well ahead of February 2027 if you want to sit the current version. Studying against the current outline and then discovering a revised exam at the last minute is an avoidable risk. The NRS I exam dates article tracks scheduling windows and deadlines.
Where This Credential Fits in a Career
NRS I is a foundation credential, most relevant to people who work with or around Nokia service-router platforms and the networks they operate. That includes engineers early in a service-provider career, technicians and support staff who touch router configuration, and professionals moving from general IT networking into carrier-style routing and services. Employers in telecommunications and service-provider environments are the natural audience, since the curriculum centers on MPLS-based services and Nokia routing hardware.
Because no verified salary figures are available for this credential, I will not quote any. For a balanced view of the investment, the ROI analysis, the salary guide and the NRS I jobs overview discuss what the credential does and does not signal to hiring managers. The honest summary is that it demonstrates solid fundamentals and a Nokia-specific vocabulary, which is most valuable as the first rung toward deeper routing credentials.
Key Takeaway
Book the exam only after you can explain each of the six modules aloud without notes and complete timed addressing drills without hesitation. Fundamentals exams punish gaps in basics more than they reward advanced knowledge.
Frequently Asked Questions
One. NRS I requires the 4A0-100 IP Networks and Services Fundamentals exam. It is a multiple-choice test with 40 questions and a 90-minute time limit, delivered within a 110-minute appointment that includes a 20-minute introductory survey.
The published exam fee is USD 125. Training courses are priced separately, so budget for the exam and any course as distinct costs. See the cost breakdown article for details.
No mandatory exam prerequisite is listed. Even so, comfort with basic networking concepts and some exposure to SR OS makes preparation considerably smoother, particularly for the services module.
Nokia's six modules are Introduction to Networking and Services, Service Router Components and CLI, Ethernet, The Internet Layer, IP Routing Protocol Basics, and Services Overview. They form a preparation outline rather than a weighted blueprint, so study all six.
If you are ready, yes. Nokia announced a revised exam for 2027-03-09 and an unavailability window from 2027-02-09 through 2027-03-08. Check the exam page before booking, since objectives may be updated.