JNCIA-Design Juniper Associate Design

During the requirements-gathering phase of a network design, which document best captures the business drivers and constraints provided by stakeholders?

• ALow-level design with IP addressing tables
• BStatement of requirements or business requirements document
• CAs-built diagram from a prior deployment
• DRouting protocol configuration template

A retail chain requires its new WAN to support a 99.99% monthly uptime SLA. Which design phase converts this business requirement into a specific technical constraint?

• AProof-of-concept testing
• BRequirements analysis and gap identification
• CPhysical cabling installation
• DDevice staging and burn-in

Which term describes the three-tier campus model that divides the network into core, distribution, and access layers?

• ASpine-leaf Clos topology
• BHierarchical design model
• CCollapsed core architecture
• DFabric underlay model

In a spine-leaf Clos data center fabric, every leaf switch connects to every spine switch. What is the primary traffic engineering benefit of this full-mesh between tiers?

• AAny-to-any traffic paths share the same hop count, enabling predictable, equal-cost multi…
• BLeaf switches provide default gateway services, eliminating spine routing entirely
• CSpine switches perform all Layer 2 flooding, reducing leaf CPU load
• DThe model requires fewer cables than a hierarchical three-tier design at the same scale

A small branch office needs a single network device to provide both Layer 2 switching and Layer 3 routing without a separate core tier. Which design model is most appropriate?

• AFull three-tier hierarchical model
• BSpine-leaf Clos with border leaves
• CCollapsed core architecture
• DCampus fabric with underlay and overlay

Which high-availability model runs two active devices simultaneously so both forward traffic, and a failure simply reduces capacity rather than causing an outage?

• AActive-standby with VRRP failover
• BN+1 cold-standby redundancy
• CActive-active redundancy
• DSingle-device with graceful restart

A data center core has four spine switches and one is powered off for maintenance. Traffic continues because the remaining three spines absorb the load. Which redundancy model does this describe?

• AActive-standby with preemption
• BN+1 redundancy
• CLogical redundancy via VRRP
• DPhysical redundancy via chassis clustering

In network design, what is the purpose of a fault isolation domain?

• ATo encrypt traffic between zones so failures cannot propagate
• BTo contain the blast radius of a failure so it does not cascade across the entire network
• CTo duplicate all packets so a secondary path always has warm state
• DTo consolidate all routing into a single autonomous system for simpler management

A campus network must grow from 500 to 5,000 users over three years. The design team chooses to add more access switches and uplinks rather than replacing core hardware. Which scalability approach does this represent?

• AScale-up (vertical scaling)
• BScale-out (horizontal scaling)
• COversubscription reduction
• DECMP pruning

A network engineer is designing a data center fabric that will carry large storage traffic. Which MTU configuration is required to avoid performance degradation on iSCSI and NFS flows?

• AStandard 1500-byte MTU on all interfaces
• BJumbo frames (MTU 9000 or 9216 bytes) end-to-end
• CMTU of 576 bytes to match legacy IP minimum
• DFragmentation enabled on all spine interfaces

Which WAN design approach uses MPLS to create logically separate Layer 3 networks over a shared provider infrastructure, commonly used by enterprises to connect branch offices?

• AIPsec overlay over the public internet
• BMPLS Layer 3 VPN (L3VPN)
• CSD-WAN with application-aware routing
• DPrivate MPLS TE with RSVP signaling only

An enterprise WAN design must support quality-of-service SLAs with guaranteed latency for voice traffic across branch sites. Which transport type is better suited to meet this requirement?

• APublic internet with best-effort delivery
• BPrivate MPLS L3VPN with SLA-backed transport
• CConsumer broadband with no QoS markings honored
• DPublic internet with IPsec but no QoS contract

Which SD-WAN capability allows the network to automatically route a voice call away from a high-latency internet link and onto a lower-latency MPLS path in real time?

• AStatic policy routing configured at design time
• BApplication-aware routing based on real-time path monitoring
• COSPF cost tuning on all WAN interfaces
• DQoS queuing at the access layer only

Which security design principle places defensive controls at multiple layers so that if one control fails, others remain in place to protect the network?

• AZero trust
• BMicro-segmentation
• CDefense in depth
• DPerimeter firewall model

A zero trust network design requires that every access request be verified regardless of where the request originates. Which assumption does zero trust explicitly reject?

• AAll internet traffic is untrusted
• BInternal network users and devices are implicitly trusted
• CEncrypted connections require additional authentication
• DMulti-factor authentication improves security

Which routing protocol characteristic makes OSPF preferable over IS-IS in a network where engineers are familiar with IP-native tooling and the domain is a single-vendor enterprise campus?

• AOSPF supports larger flooding domains and more LSP types than IS-IS
• BOSPF is IP-native with extensive vendor support, making it easier to operate with standar…
• CIS-IS cannot run in multi-area designs
• DOSPF converges faster than IS-IS in all topologies

In a data center EVPN design, BGP is selected as the control plane protocol for the fabric overlay. Which BGP address family carries MAC and IP binding information between VTEPs?

• AIPv4 unicast (AFI 1, SAFI 1)
• BVPN-IPv4 (AFI 1, SAFI 128)
• CEVPN (AFI 25, SAFI 70)
• DIPv6 unicast (AFI 2, SAFI 1)

A QoS design must ensure that voice RTP traffic is always transmitted before lower-priority data, even under congestion. Which queuing mechanism achieves this?

• AWeighted random early detection (WRED)
• BStrict priority queuing (PQ) for voice traffic
• CWeighted fair queuing (WFQ) with equal weights
• DFIFO queuing on all interfaces

A network engineer marks voice traffic with DSCP EF (Expedited Forwarding) at the access layer. What is the standard per-hop behavior associated with DSCP EF?

• ABest-effort delivery with no bandwidth guarantee
• BLow latency, low jitter, low loss, and assured bandwidth
• CExplicit congestion notification without packet drops
• DWeighted random drop to minimize global synchronization

In IPv6 design, which address assignment mechanism allows hosts to generate their own global unicast addresses using the router-advertised prefix and the host's EUI-64 or random interface ID?

• ADHCPv6 stateful
• BDHCPv6 stateless (SLAAC)
• CStateless Address Autoconfiguration (SLAAC)
• DManual static assignment

A dual-stack IPv6 design requires that an existing IPv4-only application continue to function while new IPv6 services are introduced. What does dual-stack mean in this context?

• AIPv4 is tunneled inside IPv6 packets
• BIPv6 is tunneled inside IPv4 packets
• CBoth IPv4 and IPv6 protocol stacks run simultaneously on every device
• DNAT64 translates between the two protocol versions

A network designer is selecting Juniper hardware for a high-scale internet peering router that must process millions of routes and forward at terabit-per-second speeds. Which Juniper product line is designed for this role?

• AEX Series (campus Ethernet switching)
• BQFX Series (data center switching)
• CPTX Series (high-capacity core/peering router)
• DSRX Series (security firewall)

A campus network requires Layer 2 access switching with PoE for IP phones and wireless access points. Which Juniper product family is positioned for this role?

• AMX Series
• BPTX Series
• CEX Series
• DQFX Series

What is the primary function of Juniper Apstra in a data center network design workflow?

• AProviding hardware-based packet forwarding acceleration on QFX switches
• BIntent-based networking with closed-loop validation and multi-vendor fabric management
• CRouting protocol acceleration for large BGP tables on MX routers
• DSecurity policy enforcement for east-west traffic within the data center

Which document type provides an accurate snapshot of the network as it was actually built, including interface IP addresses, VLAN assignments, and device interconnections, for use in troubleshooting and future design work?

• AHigh-level design (HLD) document
• BStatement of requirements
• CAs-built diagram and documentation
• DChange request ticket

During a network design engagement, the customer states that their ERP system must never be unreachable for more than 30 seconds during a failure event. Which design artifact captures this requirement as a measurable technical specification?

• APhysical rack diagram
• BService level agreement and recovery time objective (RTO)
• CSpanning tree configuration template
• DBGP community policy document

In the hierarchical network design model, which layer provides policy enforcement, route summarization, and aggregation between the access and core layers?

• ACore layer
• BDistribution layer
• CAccess layer
• DCollapsed layer

A large financial services company is designing a new data center and requires that any east-west server-to-server flow pass through no more than two forwarding hops. Which design model best achieves this?

• AThree-tier hierarchical with separate core, distribution, and access
• BTwo-tier spine-leaf Clos fabric
• CCollapsed core with stacked access switches
• DHub-and-spoke WAN topology extended into the data center

What is a campus fabric in the context of Juniper's enterprise campus design?

• AA pure Layer 2 flat network with a single VLAN for all users
• BAn IP fabric using EVPN-VXLAN that extends data center fabric architecture to campus wiri…
• CA proprietary Juniper protocol for stacking EX switches
• DA WAN overlay connecting campus sites using GRE tunnels

Physical redundancy and logical redundancy both contribute to high availability. Which option is an example of physical redundancy?

• AVRRP providing a virtual default gateway IP shared between two routers
• BDual power supplies in a single chassis
• COSPF with equal-cost multipath routing
• DBGP fast external failover timer

Which design consideration limits the size of an OSPF area to avoid excessive SPF computation and LSA flooding overhead as the network grows?

• AThe number of BGP peers in the area
• BThe IGP flooding domain size — too many LSAs cause CPU and convergence problems
• CThe number of MPLS labels allocated per area
• DThe physical distance between routers in the area

A network designer must connect 200 branch offices to a central hub site. Which WAN topology minimizes the number of circuits while allowing any branch to communicate with the hub?

• AFull mesh
• BHub-and-spoke
• CPartial mesh
• DRing topology

An enterprise is replacing its MPLS WAN with internet-based SD-WAN to reduce costs. What is a critical design consideration when moving voice traffic from private MPLS to public internet transport?

• AInternet transport always delivers lower latency than MPLS
• BVoice SLA requirements may not be met by best-effort internet; active path monitoring and…
• CSD-WAN cannot carry VoIP traffic over internet links
• DVoice calls must be converted to video before traversing the internet

Which security design strategy divides the network into fine-grained policy zones where workloads can only communicate with explicitly permitted destinations, reducing lateral movement after a breach?

• ADefense in depth
• BPerimeter firewall model
• CMicro-segmentation
• DNetwork address translation

A network design requires classifying traffic into DSCP classes at the network edge. Which device in the design should mark DSCP values as close to the traffic source as possible?

• ACore router, since it has the highest throughput
• BAccess layer switch or first-hop router at the network edge
• CInternet service provider's PE router
• DDestination server NIC

Which DSCP Assured Forwarding (AF) group provides the highest throughput guarantee with the lowest drop precedence within the AF class?

• AAF11 (DSCP 10)
• BAF41 (DSCP 34)
• CAF43 (DSCP 38)
• DAF31 (DSCP 26)

A designer must assign IPv4 address space to a new campus segment with exactly 60 hosts. Which subnet mask provides the minimum address space to accommodate these hosts without wasting addresses?

• A/24 (254 usable hosts)
• B/26 (62 usable hosts)
• C/27 (30 usable hosts)
• D/25 (126 usable hosts)

In a VLSM (Variable Length Subnet Masking) address plan, what is the key advantage over classful addressing?

• AVLSM eliminates the need for a default gateway
• BVLSM allows subnets of different sizes within the same address block, reducing waste
• CVLSM forces all subnets to use the same mask for simpler routing
• DVLSM removes the need for NAT in enterprise networks

Why does BGP scale better than OSPF for large internet or inter-domain routing environments?

• ABGP uses Dijkstra's SPF algorithm, which is more efficient than distance-vector at scale
• BBGP uses incremental updates and path attributes for policy, while OSPF floods full topol…
• CBGP does not require session establishment, reducing control plane overhead
• DBGP eliminates routing loops through split-horizon, unlike OSPF

In a data center IP fabric design, IS-IS is chosen over OSPF as the underlay IGP. Which operational advantage does IS-IS provide in this context?

• AIS-IS supports IPv6 natively in the same PDUs without a separate OSPFv3 instance
• BIS-IS converges more slowly, allowing time for ECMP path computation
• CIS-IS eliminates the need for BFD for fast failure detection
• DIS-IS requires fewer router IDs, simplifying large-scale address planning

A QoS policy must prevent a single department's video streaming traffic from consuming all available WAN bandwidth and starving business-critical applications. Which QoS mechanism enforces a maximum rate limit on that traffic?

• APriority queuing
• BTraffic policing or shaping
• CWRED
• DDSCP remarking at the access layer

Which DHCPv6 mode provides IPv6 addresses AND additional options (like DNS server), while the host also uses SLAAC for address configuration?

• ADHCPv6 stateful (M-flag set, O-flag unset)
• BDHCPv6 stateless (M-flag unset, O-flag set)
• CSLAAC-only (M-flag unset, O-flag unset)
• DManual static assignment with DHCPv6 reservations

A Juniper SRX Series firewall is positioned in a design to protect the perimeter of an enterprise network. Which additional security design feature of the SRX makes it appropriate for this role beyond basic stateful packet filtering?

• ALayer 3 routing with OSPF and BGP support only
• BApplication-layer identification, IPS, and UTM services
• CFabric-level VXLAN termination for data center east-west traffic
• DPoE provisioning for IP phones at the access layer

In which phase of the network design lifecycle does the designer validate that the proposed design meets all documented requirements before full deployment?

• ARequirements gathering
• BProof-of-concept or lab validation
• CImplementation and rollout
• DPost-implementation monitoring

Juniper Apstra's 'intent-based networking' model stores the desired network state separately from device configuration. What operational benefit does this provide during network changes?

• AIt prevents any configuration changes from being applied without physical access
• BIt allows operators to validate and preview configuration diffs before deployment, and to…
• CIt stores device configurations in a vendor-specific binary format for security
• DIt replaces the need for routing protocols by computing all forwarding paths centrally

A network design document includes both a logical topology diagram and a physical topology diagram. What information does the logical topology diagram convey that the physical diagram does not?

• ACable types and connector specifications
• BRack unit positions and power draw
• CIP addressing, routing protocol adjacencies, VLAN assignments, and traffic flows
• DSerial numbers and hardware models

In a high-availability design, which technology uses Bidirectional Forwarding Detection (BFD) to accelerate failure detection below the threshold of routing protocol hello timers?

• ASNMP traps for link failure notification
• BBFD-coupled control-plane failover for OSPF, IS-IS, or BGP sessions
• CIPFIX flow monitoring for traffic drops
• DSyslog alerts sent to the NOC