Data Center Interconnect

JNCIP-DC · 50 questions

• A city links its primary data center to a DR data center with dark fiber and must classify that path for a JNCIP-DC DCI design review. Which interconnect network type does dark fiber represent?
• A county can connect its two data centers only over a routed IP WAN with no native Layer-2 metro service. Which DCI implication follows for model selection?
• A township buys a Layer-2 metro Ethernet handoff between two halls and plans to stretch VLANs across it for DCI. Which characteristic should the design assume?
• A municipal fabric design places MPLS PE routers between two data centers as the DCI underlay. How should that interconnect network type be treated?
• A public-safety agency must carry encrypted DCI traffic between sites over the Internet. Which interconnect awareness is most appropriate for the DCI design?
• A city compares two leaf-spine pods in one campus with two geographically separate data centers. Which statement correctly distinguishes true DCI?
• A city asks whether EVPN-VXLAN DCI requires purchasing a special DCI-only switch product SKU. What should the architecture answer emphasize?
• Latency and bandwidth limits on a county's DCI interconnect are forcing a redesign of stretch options. Which design principle applies?
• A regional WAN team owns the circuits between municipal data centers while the DC fabric team owns EVPN-VXLAN overlays. Which handoff is correct for DCI interconnect types?
• A dark fiber cut isolates a city's primary and DR data centers that had only one DCI path. Which interconnect design response is required?
• Municipal planners confuse Metro Ethernet E-Line with E-LAN when choosing a DCI interconnect service. Which mapping is correct at the concept level?
• Ops proposes naively stretching the same IP fabric underlay ASN across two city data centers over the WAN. What boundary concern should be raised?
• A citizen-identity application must keep the same Layer-2 subnet active in both municipal data centers. Which DCI stretch approach matches that requirement?
• A finance VRF in a county fabric only needs routed reachability between sites, not a shared broadcast domain. Which stretch model fits?
• A city fears broadcast storms if it stretches Layer-2 segments between data centers. Which L2-versus-L3 stretch tradeoff should guide the decision?
• A municipal DR runbook keeps cold VMs offline until failover and requires those VMs to retain the same IP and MAC after moving to the DR hall. Why is Layer-2 stretch a fit?
• Most township applications are reachable by IP with DNS-based geo steering and do not need shared L2 adjacency between halls. Which DCI preference follows?
• A municipal design needs some VNIs Layer-2 stretched between DCs while other tenants need Layer-3 reachability only. Which stretch approach is appropriate?
• After a city enables Layer-2 stretch DCI, ARP floods are observed crossing the WAN. What BUM impact should operators expect from L2 stretch?
• Border leaves between two county EVPN fabrics exchange IP prefixes for L3 stretch. Which EVPN mechanism commonly supports that Layer-3 stretch concept?
• A city wants active/active Layer-2 stretch across two halls. Which design caution is essential?
• A township runs active/passive DR with warm standby servers and needs only routed connectivity until failover. Which DCI stretch model is typically simpler?
• A municipal team duplicates the same subnet in both data centers without intentional stretch and then sees routing conflicts. What addressing lesson applies?
• A security team bans Layer-2 stretch for a PCI segment between city data centers. Which policy-driven DCI choice follows?
• Two municipal EVPN fabrics use different VNI number spaces, and border devices must join overlay domains for DCI. Which stitching concept applies?
• A city interconnects two EVPN-VXLAN sites where Site A uses VNI 10000 for a tenant segment and Site B uses VNI 20000 for the same logical tenant. What does stitching at the DCI border primarily provide in this design?
• Municipal ops says two VRFs are “stitched” because a static route leaks prefixes between them on a border router. For JNCIP-DC DCI concepts, how should that claim be corrected?
• A single municipal border leaf terminates every DCI stitch for three sites and now shows high control-plane and forwarding load. What design lesson should the fabric team apply?
• During a civic DCI design review, engineers debate “seamless stitch” versus re-encapsulation between overlay domains. What is the sound high-level takeaway for JNCIP-DC?
• After a township DCI stitch change, Site A learns remote MACs for a tenant VNI but Site B never installs the corresponding EVPN MAC routes from Site A. What is the most likely conceptual problem?
• A township wants DCI stitching only for the Parks department VNI and must keep other departmental overlays site-local. Which approach matches that requirement?
• A city adds dual stitch gateways for redundancy and then sees Layer-2 loops for a stretched segment across the interconnect. What design care does this highlight?
• Site A runs Centrally Routed Bridging (CRB) while Site B runs Edge Routed Bridging (ERB). The municipal DCI team will stitch the two overlays. What must the design reconcile carefully?
• City documentation labels the DCI border device a “stitch PE.” In JNCIP-DC DCI terms, what role does that name map to?
• For interconnecting municipal data centers per JNCIP-DC DCI objectives, which model is the preferred blueprint approach?
• A city extends overlay reachability by establishing EVPN route exchange between border gateways at each remote site. What does that session design primarily provide for EVPN-VXLAN DCI?
• Planners must choose how a civic application spans two DCs: keep the same L2 segment stretched, or interconnect only at L3. In EVPN-VXLAN DCI terms, which statement is correct?
• Between two municipal DCs the metro path is plain IP, while tenant traffic uses VXLAN overlays signaled by EVPN. What does this reinforce about EVPN-VXLAN DCI?
• Site A and Site B use different EVPN route-target schemes for the same logical tenants. What DCI planning step is essential before multi-site membership works?
• Ops brings up EVPN BGP between municipal DCI borders and sees Type-5 prefixes exchanging, yet VXLAN-encapsulated tenant packets never arrive. Underlay ping between border VTEP addresses fails. What is the core issue?
• A civic VM moves from DC-East to DC-West over an EVPN-VXLAN DCI that stretches the tenant L2 VNI. Which EVPN behavior should operations expect?
• Security asks that DCI EVPN signaling for the municipal interconnect run in a dedicated routing instance rather than sharing the production tenant instance casually. What design hygiene does that request reflect?
• A legacy slide deck still compares municipal multi-site L2 to VPLS. For JNCIP-DC exam focus, what should candidates prioritize?
• NOC validates municipal EVPN-VXLAN DCI after a change window. Which checklist best confirms both planes are healthy?
• The municipal NOC’s DCI dashboard must prove the remote DC gateway is still exchanging EVPN with the local border. What should operators monitor first?
• L2 stretch across the city’s DCI works, but unknown unicast and broadcast traffic is saturating the WAN links. What troubleshooting focus is appropriate?
• A remote municipal VRF is missing Type-5 prefixes that the local DCI border advertises for L3 interconnect. Where should troubleshooting start conceptually?
• During a large civic VM evacuation, the stitch gateway CPU spikes while MAC/IP routes churn across the DCI. What should the ops team monitor and plan for?
• An engineer configures the municipal interconnect overlay but sources VXLAN from the wrong VTEP address on the DCI-facing device. What is the likely result?
• Packet capture on the municipal WAN path between DCI borders shows IP routing and BGP, but no UDP 4789 VXLAN traffic during a tenant flow test that should traverse EVPN-VXLAN DCI. What should troubleshooting focus on?