VPN Technologies

ENARSI · 60 questions

• A school district WAN team describes a Label Switching Router in the middle of a provider-managed MPLS path toward city hall. What is that mid-path LSR's primary job along the LSP?
• A fire-district IT team needs to explain how neighboring LSRs learn which MPLS labels to use for IGP-reachable prefixes. Which protocol fulfills that label-distribution role in classic MPLS operations?
• A police records bureau traces a civic packet that enters the provider edge as plain IP, crosses the core labeled, and leaves unlabeled toward the far CE. Which describe-level sequence best matches that MPLS behavior?
• An assessor's office defines how labeled packets traverse the provider cloud toward a remote township. What does an LSP represent in that MPLS model?
• A building-permits office contrasts hop-by-hop IP routing with MPLS on its leased civic WAN. Why does MPLS label switching differ from pure IP routing at describe depth?
• A public-health department identifies where customer IP traffic from a library VRF first receives an MPLS label on a managed provider path. Which role performs that ingress label imposition?
• A wastewater treatment plant identifies which device removes MPLS labels before delivering traffic to a township CE. Which role performs that egress disposition?
• A municipal 911 PSAP studies penultimate-hop popping on the provider path into its PE. What does PHP mean at ENARSI describe depth?
• A county elections office expects MPLS LSPs for civic prefixes to track the same forwarding path the IGP prefers. What describe-level relationship supports that expectation?
• A civic data center sees an LDP session down between P routers that still have IGP adjacency. What is the most likely describe-level impact on MPLS forwarding?
• A regional planning commission maps roles on a managed MPLS service that connects county sites. Which distinction is correct at describe depth?
• A municipal fiber consortium explains how one provider MPLS core can carry separated tables for multiple civic customers. What capability is MPLS enabling at that describe level?
• A city traffic-operations center notes both a VPN label and an IGP/transport label on PE-to-P links for L3VPN traffic. What does that two-label stack represent at describe depth?
• A county jail facilities team assumes a managed MPLS path inherently encrypts inmate-records traffic between sites. What is the accurate describe-level statement?
• A public-library branch verifies describe-level behavior of LSPs for traffic to HQ and back. What implication follows from LSPs being unidirectional?
• A municipal hospital campus WAN uses a provider MPLS L3VPN so courts and parks keep separate routing tables on shared PE routers. What PE construct primarily enforces that customer separation?
• A city IT team needs the control-plane mechanism that carries VPNv4 prefixes between PE routers for multi-site agency L3VPNs. Which technology fills that role?
• A county network team sees two townships using identical RFC1918 prefixes that must both appear uniquely in MP-BGP. Which MPLS L3VPN element makes those overlapping prefixes unique in the VPN address family?
• A township public-works department needs PE VRF policy that controls which VPN routes are installed into a given VRF. Which MPLS L3VPN construct provides that import/export membership control?
• A municipal water utility describes how a housing-authority CE can exchange routes with the provider PE on an MPLS L3VPN attachment. Which statement is accurate at describe depth?
• A transit authority separates agency routing tables on a single civic edge router with VRF-Lite and no provider MPLS core. How does that differ from a managed MPLS Layer 3 VPN service connecting those agencies across many sites?
• A port authority wants library branches, the main port HQ, and a remote annex to reach each other any-to-any inside one managed MPLS L3VPN. Which route-target design best supports that full-mesh reachability?
• An airport authority wants branch fire-station sites to reach HQ services through a hub PE, not each other directly, in a managed MPLS L3VPN. Which RT patterning describes that hub-and-spoke VPN?
• A housing authority engineer traces a VPN packet from a PE toward the P core. Besides the VPN (inner) label that identifies the customer VRF, what outer label does the PE typically impose for transport across the provider backbone?
• A library consortium connects simple CE routers to a provider PE for a managed MPLS L3VPN. What is typically true about MPLS awareness on those customer CE devices?
• Two merged county agencies keep identical RFC1918 plans for courts and parks after consolidation. How can an MPLS L3VPN still isolate those overlapping addresses across the provider network?
• A city clerk’s office asks how a managed MPLS L3VPN separates control-plane signaling from packet forwarding for multi-site agency VRFs. Which description is accurate?
• A parks department compares a carrier-managed MPLS L3VPN for dense campus sites against building DIY DMVPN over the Internet for a few sparse trailhead offices. When is the managed L3VPN service the more appropriate describe-level choice?
• A sanitation department needs a shared-services VPN (DNS, logging) reachable from multiple agency VRFs without merging those agencies into one flat table. Which MPLS L3VPN concept applies?
• An emergency-management office reviews a managed MPLS L3VPN diagram and asks whether core P routers must hold each agency’s customer VRF routing tables. What is the describe-level answer?
• A school district wants remote library branches to reach HQ over Internet circuits with dynamic tunnels and minimal per-spoke static crypto endpoints. Which single-hub design matches that ENARSI use case?
• A fire-district IT team configures the HQ DMVPN hub so one tunnel interface can terminate tunnels from many remote stations. Which tunnel mode property enables that multipoint behavior?
• A police records bureau is building single-hub DMVPN. What role do GRE/mGRE encapsulations play before IPsec protection is applied?
• An assessor’s office brings a new spoke online in a single-hub DMVPN. What does NHRP registration accomplish for that spoke?
• A building-permits office wants two branch spokes to exchange traffic directly after the first packets hairpin via HQ. Which NHRP behavior enables those dynamic spoke-to-spoke NBMA mappings?
• A public-health department runs DMVPN over Internet underlays carrying citizen health records between clinics and HQ. Why is IPsec commonly bound to the DMVPN tunnels?
• A wastewater treatment plant adds new fire-station spokes to an existing single-hub DMVPN without provisioning a unique static tunnel destination on the hub for each station. What DMVPN capability enables that?
• A municipal 911 PSAP checks whether inter-branch video is using a direct spoke-to-spoke DMVPN shortcut instead of hairpinning through HQ. Which verification cue best indicates the shortcut formed?
• A county elections office finds that DMVPN spokes can reach the hub but never form direct spoke-to-spoke paths, so inter-branch traffic keeps hairpinning. Which cause fits that symptom at ENARSI depth?
• A civic data center designs single-hub DMVPN for township offices that use DHCP public addresses from local ISPs. How should NBMA addressing typically be planned for the hub versus the spokes?
• A regional planning commission needs township prefixes to converge over a single-hub DMVPN overlay after tunnels are up. Which approach fits ENARSI config/verify practice?
• A municipal fiber consortium sees a spoke that cannot pass overlay traffic. Before blaming NHRP mappings, what protected-DMVPN prerequisite should the engineer confirm?
• A city traffic-operations center wants IPsec to encrypt traffic on its DMVPN mGRE interfaces without a separate crypto map per spoke peer. Which binding approach is the usual DMVPN pattern?
• A county jail facilities team verifies spoke NHRP configuration for single-hub DMVPN. What must spokes typically point to as their Next Hop Server?
• A public-library branch renumbers its ISP public address. Afterward, DMVPN peers still show an old NBMA mapping for that spoke and tunnels misbehave. What NHRP troubleshooting focus fits?
• A municipal hospital campus WAN sees broken large transfers across DMVPN after enabling GRE with IPsec. What adjustment best addresses encapsulation overhead on those civic VPN links?
• A city IT team documents risks of a single-hub DMVPN connecting remote libraries. What scaling limitation should they acknowledge at ENARSI single-hub depth?
• A county network team finds a new township spoke never appears in DMVPN mappings. Which misconfiguration most directly prevents NHRP registration with the hub?
• A township public works engineer secures DMVPN with IPsec but tunnels stay down. What selector requirement must the crypto profile allow between peers?
• A municipal water utility must prove dynamic DMVPN tunnels are healthy before a council network demo. Which verification approach best confirms overlay state?
• A transit authority designs DMVPN so bus-yard routers keep public Internet reachability separate from tunnel overlay addressing. What separation must operators maintain?
• A port authority wants marine-ops spokes to build direct tunnels after initial hub contact. Which NHRP behaviors enable that spoke-to-spoke shortcut path?
• An airport authority exposes a DMVPN hub to the Internet and wants to reduce fake mapping risk. What is the purpose of NHRP authentication in that design?
• A housing authority wants remote site routers to prefer simple summary or default routing via the DMVPN hub instead of carrying every remote prefix. What hub-side routing practice supports that scalability goal?
• A library consortium sees intermittent IPsec failures to one DMVPN spoke after the spoke ISP introduced asymmetric return paths. What underlay issue most likely undermines the protected tunnel?
• A county courts network team adds a new remote courthouse spoke to an existing single-hub DMVPN. What operational benefit does dynamic neighbor registration provide versus static per-spoke GRE tunnels on the hub?
• A city clerk's office streams site-to-site video between two DMVPN spokes and wants to avoid hairpinning through HQ. What benefit does a direct spoke-to-spoke IPsec path provide?
• A parks department contrasts classic hub-and-spoke forwarding with NHRP shortcut behavior on their single-hub DMVPN. What understanding matches ENARSI single-hub depth without escalating to dual-hub Phase-3 lab designs?
• A sanitation department standardizes remote-yard connectivity on DMVPN. Which approach stays inside common single-hub config-and-verify patterns expected for ENARSI?
• An emergency-management office scopes WAN VPN training to ENARSI Domain 2.3. Which boundary correctly keeps focus on DMVPN rather than FlexVPN concentration?