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The JNCIA-DC exam has 65 questions and runs 1 hours 30 minutes.
These 10 free JNCIA-DC questions are organized by exam domain, so you can see how each part of the Juniper Networks Certified Associate, Data Center blueprint is tested. Reveal the answer and explanation under each question.
A packet capture on a routed spine in an EVPN-VXLAN fabric shows outer destination IP 192.0.2.22, VNI 50100, and inner destination IP 10.20.30.40. The spine is an IP transit device, not a VTEP. Which field determines its IP route lookup for this packet?
Correct answer: B - The outer destination IP address, 192.0.2.22.
A rack leaf has forty-eight 25-Gbps server ports and four active 100-Gbps uplinks. It must retain all server ports and keep the server-facing-to-uplink capacity ratio below 3.5:1 after any one uplink fails. Spare ports and the proposed link speeds are supported throughout the fabric. Which proposal meets the target with the least added uplink capacity?
Correct answer: C - Add one 100-Gbps uplink.
Storage hosts communicate within each rack but not across the 802.1Q trunk between two Junos switches. Both trunk interfaces include VLAN STORAGE. Switch A assigns STORAGE VLAN ID 310; Switch B assigns it VLAN ID 311. Other VLANs cross the trunk successfully. VLAN translation is not configured, and the agreed storage tag is 310. The repair should be to:
Correct answer: D - Set Switch B's STORAGE VLAN ID to 310.
An engineer is completing this ELS configuration for VLAN APP on a Junos switch. The host-facing port should remain a switching port, and 10.42.0.1/24 should provide the VLAN's routed interface. No VLAN-to-IRB association has been configured. set vlans APP vlan-id 420 set interfaces ge-0/0/8 unit 0 family ethernet-switching interface-mode access set interfaces ge-0/0/8 unit 0 family ethernet-switching vlan members APP set interfaces irb unit 42 family inet address 10.42.0.1/24 Select the statement that completes the Layer 3 association from the top configuration hierarchy.
Correct answer: D - set vlans APP l3-interface irb.42
A packet for 10.80.24.90 reaches a Junos leaf. Each route below is active, its next hop is installed in the forwarding table, and every next hop is reachable. 10.80.0.0/16 - static, preference 5, next hop 192.0.2.1 10.80.24.0/24 - OSPF, preference 10, next hop 192.0.2.2 10.80.24.128/25 - BGP, preference 170, next hop 192.0.2.3 10.80.24.0/26 - static, preference 5, next hop 192.0.2.4 Which next hop receives the packet?
Correct answer: C - 192.0.2.2
A leaf's contributor policy accepts approved /24 routes within 10.92.0.0/16, each with a usable IP next hop. Its export policy advertises the /16 summary only while that summary is active. The route design must meet two conditions: • Withdraw the summary when its last accepted active contributor is lost. • Silently drop packets covered by the /16 but by no installed more-specific route. Select the route that meets both conditions.
Correct answer: D - A conditional aggregate route with a discard next hop.
An operations dashboard flags R4's OSPFv2 relationship with R3 as faulty. Four routers share the same broadcast Ethernet segment, and R4 is a DROther. R4 reports: R1 - DR - Full R2 - BDR - Full R3 - DROther - 2-Way All expected OSPF routes are present, and traffic is forwarding normally. How should the operator respond to this alert?
Correct answer: A - Keep the configuration; 2-Way is expected between these two DROthers.
A Junos router compares two eligible BGP paths to 203.0.113.0/24. Both have equal routing-protocol preference and reachable next hops: East exit: LOCAL_PREF 180; AS-path length 4; IGP cost to next hop 40. West exit: LOCAL_PREF 160; AS-path length 2; IGP cost to next hop 5. Which path wins this comparison, and why?
Correct answer: B - East: its higher LOCAL_PREF wins before AS path or IGP cost.
An OSPFv2 area connects to area 0 through an ABR. Its routers must retain specific interarea routes and exclude type 5 external LSAs received from the backbone. A router with all of its OSPF interfaces inside this area must also redistribute static service prefixes. Which area type supports this design?
Correct answer: B - NSSA with interarea summaries.
A new two-link server bundle has carrier on both members, matching speeds, and correct member assignments. Both the switch and server are configured for LACP passive mode. Neither side has transmitted an LACP PDU, and the bundle has no eligible forwarding members. No fallback mechanism is enabled. What will initiate negotiation?
Correct answer: A - Set the switch to LACP active mode.
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