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100+ Free JNCDS-WAN Practice Questions

Pass your Juniper Networks Certified Design Specialist, WAN (JNCDS-WAN) exam on the first try — instant access, no signup required.

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In a Juniper SD-WAN design with Mist WAN Assurance, what is the purpose of "WAN probing" between branch SRX gateways?

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2026 Statistics

Key Facts: JNCDS-WAN Exam

65

Exam Questions

Juniper Networks

90 min

Exam Duration

Juniper Networks

$300

Exam Fee

Juniper Networks

3 years

Certification Validity

Juniper Networks

~25% each

SD-WAN + MPLS Weight

Top two domains

JN0-1363

Exam Code

Juniper Networks

The JNCDS-WAN exam has 65 questions in 90 minutes. Key topics: SD-WAN (~25%), MPLS design (~25%), Segment Routing (~20%), Class of Service (~15%), WAN automation (~15%). Exam fee: $300 via Pearson VUE. Valid 3 years. Prerequisite: JNCDA recommended with JNCIS-SP/JNCIP-SP experience.

Sample JNCDS-WAN Practice Questions

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

1A WAN designer is evaluating SD-WAN solutions for a retail chain with 500 branch sites. Which Juniper solution provides centralized SD-WAN policy management, application-aware routing, and WAN assurance from the cloud?
A.Juniper Mist AI with WAN Assurance, deploying SRX Series gateways managed from the Mist cloud portal
B.Juniper Apstra managing QFX switches at each branch location
C.OSPF with equal-cost multipath across all WAN links
D.Manual static routing with floating static routes as backup
Explanation: Juniper Mist AI with WAN Assurance provides cloud-managed SD-WAN capabilities using SRX branch gateways. It delivers centralized policy management, application identification and steering, dynamic path selection based on link quality, and AI-driven insights for WAN performance. This is Juniper's primary SD-WAN solution as of 2026 following the Mist-SRX integration.
2In an MPLS network design, what is the purpose of a Label Edge Router (LER) at the customer edge?
A.Assign MPLS labels to incoming IP packets (imposition) at network ingress and remove labels from packets leaving the MPLS cloud (disposition)
B.Propagate MPLS labels to customer CE devices using LDP
C.Perform MPLS FRR (Fast Reroute) path computation for link protection
D.Terminate BGP sessions from all P routers in the core
Explanation: A Label Edge Router (LER) is the ingress/egress device at the boundary of the MPLS network. At ingress (PE router), the LER imposes (pushes) MPLS labels onto incoming IP packets to create a labeled LSP path. At egress, the LER disposes (pops) labels and forwards the original IP packet to the destination. The MX Series is Juniper's primary PE/LER platform.
3When designing an MPLS-based L3VPN (RFC 4364) service for enterprise customers, which BGP address family carries customer routes between PE routers?
A.MP-BGP with the VPNv4 address family (AFI 1, SAFI 128) to carry customer routes with a Route Distinguisher prepended to make them globally unique
B.Standard BGP with IPv4 unicast and community attributes to tag customer routes
C.OSPF with route redistribution between customer VRFs
D.LDP with targeted LDP sessions between all PE routers
Explanation: MP-BGP VPNv4 (Multiprotocol BGP with Address Family Identifier 1, Subsequent AFI 128) carries customer IPv4 routes between PE routers in an MPLS L3VPN. Each customer route is prepended with a Route Distinguisher (RD) to ensure global uniqueness, even when customers use overlapping private IP space. Route Targets (RTs) control which VRFs import/export these routes.
4In a Segment Routing (SR-MPLS) design, what is the key advantage of Segment Routing over traditional MPLS with LDP or RSVP-TE?
A.Segment Routing encodes the entire path in the packet header at the ingress node, eliminating the need for per-flow state in transit (P) routers and removing the need for LDP/RSVP signaling protocols
B.Segment Routing provides higher throughput by using a compressed label stack of a single label for all traffic
C.Segment Routing requires a separate out-of-band controller for all forwarding decisions
D.Segment Routing replaces BGP as the WAN routing protocol
Explanation: Segment Routing is a source-routing paradigm where the ingress node (headend) encodes the complete path as an ordered list of segments (MPLS labels or IPv6 SRv6 SIDs) in the packet header. Transit (P) routers perform simple label swap/pop operations based on the header; they require no per-flow RSVP state or LDP bindings. This simplifies the control plane dramatically.
5A WAN designer needs to provide strict bandwidth guarantees for voice traffic (G.711 and G.729 codecs) across an MPLS WAN. Which Class of Service (CoS) mechanism provides these guarantees?
A.Strict Priority (Expedited Forwarding) queuing for voice traffic ensures voice packets are always forwarded before lower-priority traffic, minimizing latency and jitter
B.Weighted Random Early Detection (WRED) applied to the voice queue
C.Tail drop on all queues with a small buffer for voice packets
D.OSPF route metric manipulation to route voice through lower-capacity links
Explanation: Strict Priority (SP) queuing — corresponding to the Expedited Forwarding (EF) DSCP per-hop behavior — drains the voice queue before serving any other queue. This guarantees bounded latency and near-zero jitter for voice traffic. Voice is typically marked DSCP EF (46) and placed in the strict priority queue with a bandwidth policer to prevent starvation of other queues.
6In a Junos MX-based WAN design, what is the function of the Routing Engine (RE) and Packet Forwarding Engine (PFE)?
A.The RE runs routing protocols and computes the routing table; the PFE performs hardware-based forwarding of packets at line rate using the forwarding table downloaded from the RE
B.The RE forwards all packets; the PFE handles only management plane functions
C.Both RE and PFE run separate instances of OSPF to provide redundancy
D.The PFE computes BGP routes; the RE handles physical interface statistics
Explanation: Junos separates the control plane (Routing Engine) from the data plane (Packet Forwarding Engine). The RE runs routing daemons (BGP, OSPF, IS-IS, etc.) and maintains the routing table (RIB). It downloads the forwarding table (FIB) to the PFE. The PFE uses custom ASICs (Trio chipset on MX) to forward packets at line rate in hardware without RE involvement.
7When designing a WAN with MPLS Traffic Engineering (MPLS-TE), which protocol is responsible for signaling RSVP-TE Label Switched Paths (LSPs) based on constrained path computation?
A.RSVP-TE with CSPF (Constrained Shortest Path First) using TE link attributes advertised by OSPF-TE or IS-IS-TE as topology input
B.LDP with targeted sessions between all PE routers in the MPLS cloud
C.BGP with the IPv4 unicast address family and TE community attributes
D.BFD with aggressive timers to detect link failures and trigger LSP failover
Explanation: RSVP-TE signals Label Switched Paths by reserving resources (bandwidth) along a computed path. CSPF uses the TE topology (link bandwidth, admin groups, SRLG data) advertised via OSPF-TE or IS-IS-TE extensions to compute a path that satisfies the LSP's constraints. The headend router then signals the path using RSVP PATH and RESV messages.
8A designer is implementing Segment Routing with IS-IS for a service provider WAN. Which segment type represents a globally unique identifier for a specific router in the SR domain?
A.Node SID (Prefix Segment ID), assigned to the router's loopback and advertised via IS-IS with the N-flag set
B.Adjacency SID, assigned to a specific link between two routers
C.Binding SID, used to reference a pre-computed SR policy
D.Traffic Engineering SID, assigned per LSP for RSVP-TE integration
Explanation: A Node SID (Prefix Segment) is a globally unique MPLS label (or IPv6 SID) assigned to a router's loopback prefix. It is advertised throughout the SR domain by IS-IS with the Node-flag (N-flag) set, meaning the segment represents the node itself rather than a prefix. Node SIDs are drawn from the Segment Routing Global Block (SRGB) and enable source-based routing to any router in the domain.
9In a Juniper Paragon Pathfinder deployment, what is the role of Pathfinder in a Segment Routing WAN?
A.Act as a Path Computation Element (PCE) that computes optimized SR-TE paths based on real-time network topology and traffic demand, then instantiates SR policies on headend routers via PCEP
B.Provide centralized DHCP address allocation for all WAN routers
C.Terminate all BGP sessions from customer CE devices
D.Run OSPF and IS-IS simultaneously to provide topology redundancy
Explanation: Juniper Paragon Pathfinder is a Path Computation Element Controller (PCE-C) for SR-MPLS and RSVP-TE WAN networks. It collects real-time topology and traffic demand information, computes optimal TE paths using advanced algorithms, and programs SR policies or RSVP-TE tunnels on headend routers using PCEP (Path Computation Element Communication Protocol) and BGP-SR Policy.
10When designing CoS (Class of Service) for a WAN with multiple application types, what does DSCP EF (Expedited Forwarding, value 46) indicate about the traffic behavior?
A.Traffic marked EF should receive low latency, low jitter, and low loss treatment — it maps to the strict priority queue and is typically used for real-time voice/video applications
B.EF traffic is best-effort and receives default queue treatment
C.EF indicates the traffic should be dropped during congestion to protect higher-priority flows
D.EF is used exclusively for routing protocol control plane traffic
Explanation: DSCP EF (Expedited Forwarding) per RFC 3246 defines a per-hop behavior (PHB) characterized by a committed rate with bounded latency, jitter, and loss. Routers map EF to the strict priority queue, ensuring these packets are forwarded before all other traffic. EF is the standard marking for real-time applications such as VoIP (G.711, G.729) and interactive video.

About the JNCDS-WAN Exam

The JNCDS-WAN (JN0-1363) validates advanced ability to design enterprise and service provider WAN solutions. It covers SD-WAN design with Juniper Mist WAN Assurance (application-aware routing, path quality monitoring), MPLS L3VPN with VPNv4 MP-BGP, pseudowires and EVPN-VPWS, MPLS-TE with RSVP-TE, Segment Routing (SR-MPLS and SRv6), Class of Service design, and WAN automation with Juniper Paragon.

Questions

65 scored questions

Time Limit

90 minutes

Passing Score

Not publicly disclosed (estimated 60-70%)

Exam Fee

$300 (Juniper Networks / Pearson VUE)

JNCDS-WAN Exam Content Outline

~25%

SD-WAN Design

Juniper Mist WAN Assurance architecture, SRX branch gateways, application-aware routing (AAR) with per-path quality monitoring, WAN probing (latency/jitter/loss), MOS-based SLA, ZTP for branch deployment, IPsec encryption for internet transport

~25%

MPLS Design

MPLS L3VPN (RFC 4364) VPNv4 MP-BGP, RD/RT design, VRF routing instances on MX, pseudowires (LDP Martini and EVPN-VPWS RFC 8214), MPLS-TE with RSVP-TE and CSPF, MPLS FRR node protection bypass tunnels, SRLGs

~20%

Segment Routing

SR-MPLS source routing principle, Node SIDs (prefix segments) and Adjacency SIDs, SRGB, SR-TE policies with candidate paths and preference, inter-domain SR with H-PCE (Paragon Pathfinder via PCEP), BGP-LS topology export, SRv6 with SRH

~15%

Class of Service

Behavior Aggregate (BA) classifiers for DSCP, DSCP marking per RFC 4594 (EF for voice, AF41 for video, CS6 for routing protocols), scheduler CIR and guaranteed bandwidth, strict priority queuing, WRED for TCP traffic, CoS on MX Trio chipset

~15%

WAN Automation and Platform Design

Paragon Pathfinder (PCE for SR-TE/RSVP-TE via PCEP), Paragon Planner (what-if capacity simulation), Paragon Insights (multi-layer IP/optical correlation), IS-IS L1/L2 route leaking, MX platform RE/PFE architecture, hub-and-spoke BGP path preference

How to Pass the JNCDS-WAN Exam

What You Need to Know

  • Passing score: Not publicly disclosed (estimated 60-70%)
  • Exam length: 65 questions
  • Time limit: 90 minutes
  • Exam fee: $300

Keys to Passing

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

JNCDS-WAN Study Tips from Top Performers

1Know MPLS L3VPN roles: CE (customer edge), PE (provider edge/LER), P (provider core/LSR) — MX is always the PE/LER
2Understand VPNv4 MP-BGP: Route Distinguisher makes routes globally unique; Route Target controls VRF import/export
3Study SR Node SIDs: drawn from SRGB (globally unique), advertised by IS-IS with N-flag; used to encode paths at headend
4Know DSCP per RFC 4594: Voice=EF(46), Video Conf=AF41(34), Signaling=CS5, Network Control=CS6(48), Best-Effort=Default(0)
5Understand SD-WAN path selection: WAN probing measures latency/jitter/loss per path; AAR selects best path per application SLA
6Study MPLS FRR: PLR pre-computes bypass tunnel before failure; sub-50ms recovery because no SPF recalculation needed
7Know BGP-LS: exports IGP topology to external PCE (Paragon Pathfinder) for centralized TE path computation

Frequently Asked Questions

What is the JNCDS-WAN exam?

JNCDS-WAN (JN0-1363) is Juniper's WAN Design Specialist exam. It validates ability to design WAN solutions including SD-WAN with Mist WAN Assurance, MPLS L3VPN, Segment Routing (SR-MPLS/SRv6), Class of Service, and WAN automation with Paragon. The exam has 65 questions in 90 minutes via Pearson VUE.

What is the difference between SR-MPLS and traditional RSVP-TE?

SR-MPLS (Segment Routing) encodes the path in the packet header at the ingress node, eliminating per-flow RSVP state in transit nodes. Traditional RSVP-TE requires each router to maintain RSVP soft-state for every active LSP and uses explicit RSVP PATH/RESV signaling. SR-MPLS simplifies the control plane but requires traffic engineering functions to move to a centralized PCE (like Paragon Pathfinder).

What Juniper platforms are covered on JNCDS-WAN?

The primary platform is the Juniper MX Series — specifically MX10004 and MX10008 for SP PE roles. Understand the RE/PFE separation (Routing Engine for control plane, Packet Forwarding Engine with Trio chipset for data plane). ACX Series for metro aggregation, vMX for cloud PE deployments, and SRX for SD-WAN branch gateways are also relevant.

What is Paragon Pathfinder and why is it on the JNCDS-WAN exam?

Paragon Pathfinder is Juniper's Path Computation Element Controller (PCE-C) for SR-MPLS and RSVP-TE WANs. It collects topology via BGP-LS, computes optimized TE paths, and programs SR-TE policies or RSVP tunnels on routers via PCEP. As the primary WAN automation tool for Juniper SR deployments, it is a significant part of the JNCDS-WAN design exam.

How is Class of Service tested on JNCDS-WAN?

CoS questions focus on design decisions: which DSCP value to use for each traffic class per RFC 4594, when to use strict priority vs. weighted queuing, how CIR guarantees bandwidth, and how to classify traffic using BA (DSCP-based) vs. MF (multi-field) classifiers. Know EF (46) for voice, AF41 (34) for video, CS6 (48) for routing protocols, and Default (0) for best-effort.