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Question 1

Score: 0/0

Which VLAN membership mode assigns a port to exactly one VLAN and removes the 802.1Q tag before forwarding frames to the end device?

Trunk mode

Access mode

Hybrid mode

Tagged mode

to track

2026 Statistics

Key Facts: JNCIA-DC Exam

Multiple-Choice Questions

Juniper exam page

90 min

Exam Length

Juniper exam page

$200

Exam Fee

Juniper purchase options

3 years

Certification Validity

Juniper recertification policy

JN0-222

Exam Code

Juniper certification page

6 domains

Objective Areas

Juniper exam objectives

The JNCIA-DC (exam JN0-222) is Juniper Networks' associate-level data center certification. It covers 65 multiple-choice questions in 90 minutes through Pearson VUE at a $200 exam fee. Juniper does not publicly disclose a numeric passing score — candidates receive immediate pass/fail results. The exam focuses on QFX Series switching, VXLAN/EVPN overlay networking, spine-leaf Clos fabric architecture, and Junos CLI applied to data center configurations.

Sample JNCIA-DC Practice Questions

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

1Which VLAN membership mode assigns a port to exactly one VLAN and removes the 802.1Q tag before forwarding frames to the end device?

A.Trunk mode

B.Access mode

C.Hybrid mode

D.Tagged mode

Explanation: Access (untagged) ports belong to a single VLAN and strip the 802.1Q tag when sending frames to end hosts such as servers or workstations. The host does not need to understand VLAN tagging. Trunk ports, by contrast, carry multiple VLANs using tagged frames.

2On a QFX Series switch, which Junos configuration statement correctly defines VLAN 100 named 'servers'?

A.set vlans servers vlan-id 100

B.set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members 100

C.set vlan 100 name servers

D.set vlans 100 description servers

Explanation: In Junos enhanced Layer 2 software (ELS), VLANs are defined under the 'vlans' hierarchy with a name and a vlan-id. The correct syntax is 'set vlans servers vlan-id 100'. The interface assignment is a separate step that references this VLAN name.

3What is the primary purpose of a trunk port in an Ethernet switching environment?

A.To connect a single end host to exactly one VLAN

B.To carry tagged frames for multiple VLANs between switches or to virtualized hosts

C.To block all VLAN traffic and act as a security boundary

D.To aggregate multiple physical links into one logical link

Explanation: Trunk ports use 802.1Q tagging to carry frames from multiple VLANs across a single link. They are used between switches, between a switch and a router, or to hypervisors that handle multiple VLANs. Link aggregation (LAG) is a separate feature that bundles physical links.

4Rapid Spanning Tree Protocol (RSTP) improves upon original STP primarily by doing which of the following?

A.Eliminating the need for a root bridge election

B.Allowing non-root ports to reach the forwarding state faster using edge ports and rapid negotiation

C.Distributing traffic across all links simultaneously with no blocked ports

D.Using VXLAN encapsulation to carry spanning tree BPDUs

Explanation: RSTP (802.1w) reduces convergence time from 30-50 seconds to near-instantaneous by introducing edge ports (which go directly to forwarding) and rapid negotiation between switches. A root bridge is still elected, and RSTP still blocks redundant paths to prevent loops.

5Multiple Spanning Tree Protocol (MSTP) differs from RSTP by adding what capability?

A.Faster convergence using edge ports

B.Mapping multiple VLANs to individual spanning tree instances to allow load balancing

C.Eliminating spanning tree entirely by using VXLAN overlays

D.Running a separate spanning tree instance per physical port

Explanation: MSTP (802.1s) groups VLANs into Multiple Spanning Tree Instances (MSTIs), allowing different VLANs to have different root bridges and forwarding paths. This enables load balancing across redundant links without simply blocking one path for all VLANs, which is what RSTP and classic STP do.

6What does IEEE 802.3ad Link Aggregation (LAG) accomplish in a data center switching environment?

A.It allows a single physical port to carry traffic for multiple VLANs simultaneously

B.It bundles multiple physical links into one logical interface to increase bandwidth and provide redundancy

C.It creates a virtual routing instance that spans multiple switches

D.It encrypts inter-switch traffic using 802.1AE MACsec

Explanation: 802.3ad (LACP) combines multiple physical links into an Aggregated Ethernet (ae) logical interface. The result is higher aggregate bandwidth and redundancy: if one member link fails, traffic continues on the remaining links. This is different from VLAN trunking, which allows multiple VLANs on a single link.

7What is an Integrated Routing and Bridging (IRB) interface used for on a QFX Series switch?

A.To carry spanning tree BPDUs between switches in a loop-free topology

B.To provide a routed Layer 3 gateway for devices in a particular VLAN

C.To aggregate multiple physical links using LACP

D.To extend a VXLAN VNI across multiple data center sites

Explanation: An IRB interface is a logical Layer 3 interface associated with a specific VLAN. It acts as the default gateway for hosts in that VLAN, enabling inter-VLAN routing on the switch without a separate external router. IRB is the Junos equivalent of Cisco's SVI (switched virtual interface).

8In a Junos Virtual Chassis configuration on EX Series switches, what is the primary benefit?

A.Multiple physical switches appear and are managed as a single logical switch

B.Each switch in the group runs its own independent control plane and Junos instance

C.Virtual Chassis uses VXLAN tunnels to extend VLANs across geographic sites

D.Virtual Chassis replaces spanning tree by providing loop-free Layer 2 forwarding

Explanation: Virtual Chassis connects up to 10 EX Series switches (or certain QFX models) using dedicated VC ports or uplinks, making them appear as a single chassis with one management IP, one Junos image, and a unified control plane. This simplifies management and eliminates some STP requirements within the chassis.

9Multi-Chassis LAG (MC-LAG) solves which specific limitation of single-chassis LAG in a data center access layer?

A.Single-chassis LAG cannot carry tagged VLAN frames

B.Single-chassis LAG ties the LAG to one switch, creating a single point of failure; MC-LAG spans two switches to eliminate that failure domain

C.Single-chassis LAG is limited to 1 Gbps links; MC-LAG enables 100 Gbps aggregation

D.Single-chassis LAG does not support LACP; MC-LAG introduces LACP support

Explanation: Standard LAG aggregates links from a single device. If that device fails, all links in the bundle go down. MC-LAG splits the bundle across two peer switches (ICL-connected), so a server or ToR switch can dual-home to both peers. If one peer fails, the other continues to carry traffic.

10What does a VXLAN Network Identifier (VNI) represent?

A.The VLAN ID used on the underlay physical network

B.A 24-bit segment identifier that distinguishes individual VXLAN overlay networks

C.The IP address of the VTEP responsible for encapsulating frames

D.The BGP community value used in EVPN route advertisements

Explanation: A VNI is a 24-bit value in the VXLAN header that identifies which overlay network (segment) a frame belongs to. This allows up to ~16 million distinct overlay segments, far more than the 4,094 VLAN IDs available in standard 802.1Q. Multiple VLANs can be mapped to different VNIs across the same underlay.

About the JNCIA-DC Exam

JNCIA-DC validates associate-level knowledge of data center networking on Juniper QFX Series platforms. Topics include Ethernet switching fundamentals (VLANs, trunks, STP/RSTP/MSTP), link aggregation (LAG, MC-LAG), IRB gateways, Virtual Chassis, VXLAN overlay concepts (VNI, VTEP), EVPN control plane (BGP EVPN, MAC/IP routes), spine-leaf IP fabric design (eBGP underlay, ECMP), and Juniper Apstra overview.

Questions

65 scored questions

Time Limit

90 minutes

Passing Score

Unpublished by Juniper (pass/fail result shown immediately)

Exam Fee

$200 (Juniper Networks / Pearson VUE)

JNCIA-DC Exam Content Outline

Est. 14%

Data Center Fundamentals

Ethernet switching basics, VLANs, trunks, access ports, MAC learning, and data center network architecture

Est. 17%

Layer 2 Switching Features

Spanning Tree (RSTP, MSTP), Link Aggregation (802.3ad LAG), IRB interfaces, and Multi-Chassis LAG (MC-LAG)

Est. 11%

Virtual Chassis

Virtual Chassis basics on EX/QFX Series, master RE election, member roles, and simplified management

Est. 22%

VXLAN

VXLAN encapsulation, VNI, VTEP, overlay vs underlay, flood-and-learn, BUM traffic, and basic QFX configuration

Est. 22%

EVPN

BGP EVPN, route types (RT-2, RT-3, RT-5), MAC/IP learning via BGP, ARP suppression, anycast IRB, and symmetric/asymmetric IRB

Est. 14%

IP Fabric and Underlay

Spine-leaf Clos topology, eBGP and OSPF underlay routing, ECMP, loopback as VTEP source

How to Pass the JNCIA-DC Exam

What You Need to Know

Passing score: Unpublished by Juniper (pass/fail result shown immediately)
Exam length: 65 questions
Time limit: 90 minutes
Exam fee: $200

Keys to Passing

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

JNCIA-DC Study Tips from Top Performers

1Understand the spine-leaf Clos topology deeply — why no leaf-to-leaf direct links, why eBGP with unique per-device ASNs, and how ECMP uses all spine paths simultaneously.

2Practice VXLAN conceptually: trace a packet from a server through VTEP encapsulation, across the IP underlay, to VTEP decapsulation at the remote leaf.

3Know the EVPN route types by number: RT-2 (MAC/IP learning), RT-3 (BUM/multicast setup), RT-5 (IP prefix for inter-VRF routing).

4Learn the Junos CLI for data center tasks: 'show ethernet-switching table', 'show vxlan vni all', 'show evpn database', 'show bgp summary', 'show lacp interfaces'.

5Differentiate symmetric IRB (L3VNI for routed traffic, scales well) from asymmetric IRB (routing only at ingress, requires all VLANs on all leaves).

6Study Juniper Apstra at a conceptual level: intent-based networking, Blueprint as source of truth, continuous validation, and NETCONF-based configuration deployment.

Frequently Asked Questions

What is the JNCIA-DC exam code?

The JNCIA-DC exam code is JN0-222. It is delivered through Pearson VUE testing centers. The exam consists of 65 multiple-choice questions with a 90-minute time limit. Juniper does not publish a numeric passing score; candidates receive an immediate pass or fail result at the testing center.

How much does the JNCIA-DC exam cost?

The JNCIA-DC (JN0-222) exam costs $200 USD. This is consistent with other Juniper associate-level written exams. The exam can be scheduled through Pearson VUE at pearsonvue.com/junipernetworks.

What topics are covered on the JNCIA-DC exam?

JNCIA-DC covers data center networking fundamentals on Juniper QFX platforms: Ethernet switching (VLANs, trunks, access ports), Spanning Tree (RSTP, MSTP), LAG (802.3ad) and MC-LAG, IRB interfaces, Virtual Chassis basics, VXLAN (VNI, VTEP, overlay/underlay concepts), EVPN (BGP EVPN, route types, ARP suppression, anycast IRB), spine-leaf Clos architecture (eBGP/OSPF underlay, ECMP), and Juniper Apstra overview. Junos CLI basics applied to data center configurations are also tested.

What is the passing score for JNCIA-DC?

Juniper does not publicly disclose a numeric passing score for the JNCIA-DC exam. Candidates receive an immediate pass or fail notification at the Pearson VUE testing center upon completing the exam. Study to broad coverage across all objective domains rather than targeting a specific score percentage.

How long should I study for JNCIA-DC?

Candidates with general networking experience (CCNA-level or equivalent) typically need 40-70 hours of study over 3-6 weeks. Focus extra time on VXLAN/EVPN concepts and Junos CLI syntax, especially if you have a Cisco background. Candidates without networking experience should budget 80-100 hours covering TCP/IP fundamentals and Ethernet switching before tackling VXLAN and EVPN.

What is the difference between JNCIA-DC and JNCIA-Junos?

JNCIA-Junos (JN0-106) focuses on Junos OS fundamentals applicable to all platforms: CLI workflow, configuration hierarchy, routing basics, and routing policy. JNCIA-DC (JN0-222) is data center specific, covering VXLAN, EVPN, spine-leaf fabric design, QFX Series hardware, MC-LAG, and Apstra. Many candidates pursue JNCIA-Junos first as a foundation before specializing in JNCIA-DC.