Transport Technologies and Solutions

CCIE · 45 questions

• A parks department traces a civic packet between PE and P routers and sees multiple MPLS labels. What do those stacked labels typically represent?
• An emergency-management office relies on the MPLS underlay to forward labeled unicast traffic across the county core. What is LDP’s primary role in that design?
• County courts staff suspect a departmental VPN is down. What should they verify before blaming PE-CE routing?
• A city clerk must separate underlay label-switched path problems from CE routing problems. Which tools are purpose-built for LSP validation?
• An airport authority isolates department networks across a shared county MPLS core. Which architecture provides that separation?
• A port authority exchanges VPN routes between PE routers for civic VRFs. Which control-plane mechanisms distinguish and control those customer tables?
• A housing authority must extend IPv6 civic services across an MPLS core. Which approaches are conceptually appropriate at the PE layer?
• A sanitation department attaches a partner agency VRF that needs rich routing policy at the edge. Which PE-CE protocol is the usual fit?
• A fire district attaches a township that already standardized on EIGRP at the edge to an MPLS L3VPN PE. Which concern should designers keep in mind at a conceptual level?
• A police records bureau attaches an OSPF CE domain to an MPLS VPN PE. Which loop-prevention concepts should engineers keep in view?
• A municipal hospital campus needs a joint city-county CMDB application to reach a shared prefix that must remain in both the clinical VRF and the county-admin VRF without merging the rest of those tables. What MPLS L3VPN mechanism enables that controlled sharing?
• A community college district attaches identical RFC1918 CE prefixes into several VRFs and needs those routes to remain unique inside MP-BGP. What is the primary purpose of assigning a unique route distinguisher per VRF attachment?
• A regional planning commission wants clinic spoke sites to reach only a central hub VRF, not each other, over an MPLS L3VPN. How should route-target import and export be arranged?
• A 911 PSAP MPLS core team wants transit routers that only label-switch packets and never hold VRF or VPNv4 state. Which role correctly describes those devices?
• An election-office engineer packet-captures near an egress PE and notices the top transport label is already gone one hop before that PE. Which MPLS behavior most likely explains the missing top label?
• A tax-assessor VPN complaint shows missing labels between PEs even though VPNv4 routes look present on the route reflector. What should operators verify first as the foundation for MPLS L3VPN forwarding?
• A building-permits desk is reading a PE forwarding table while troubleshooting an L3VPN and must interpret how VPN labels were assigned. At a conceptual level, what does per-prefix label allocation mean?
• A fleet-garage PE is at risk of exhausting memory because one chatty CE floods excessive prefixes into its VRF. What control best protects the PE while keeping the L3VPN design intact?
• A wastewater plant edge PE must offer civic Internet exit for one VRF’s users. Which design choice correctly frames Internet in a VRF versus the global routing table?
• A stormwater bureau needs civic voice packets to keep class treatment across an MPLS core that forwards on labels. What QoS concept maps packet DSCP into the MPLS header for core classification?
• A public-health clinic network has multiple equal-cost transport LSPs between PEs carrying VPN traffic. How does ECMP typically behave for that MPLS VPN load sharing?
• An animal-control HQ PE should not import every extranet VPNv4 route advertised in the autonomous system. What control limits which VPN routes that PE accepts?
• A museums-and-culture department CE begins advertising a recursive default into the VRF and black-holes civic traffic. What PE-CE hygiene best stops that behavior?
• County IT dual-homes a city-hall CE to two PEs so a single PE failure does not isolate the site. What design outcome does that multi-homing primarily provide?
• City public-works users on an L3VPN report loss of connectivity. Which troubleshooting order best separates underlay from overlay problems?
• A municipal library consortium builds DMVPN Phase 3 so after initial hub contact, spoke libraries can build direct tunnels to each other. Which behavior characterizes that Phase 3 shortcut model?
• A township board’s DMVPN spokes still hair-pin all spoke-to-spoke traffic through the hub. Which missing Phase 3 features are the most likely cause?
• A transit authority places two DMVPN hubs on one shared mGRE cloud for hub redundancy across the county WAN. What trade-off does that dual-hub single-cloud design primarily involve?
• A water utility separates DMVPN hubs onto dual mGRE clouds so public-safety sites keep an independent path if one overlay fails. What resiliency pattern does that describe?
• A school district runs EIGRP over DMVPN Phase 3 and must keep spoke routes usable without classic hub split-horizon or next-hop problems. Which design consideration is most accurate?
• A parks department runs OSPF over DMVPN mGRE and needs stable adjacencies without treating the overlay like a broadcast LAN full of unexpected DR elections. Which approach is most appropriate?
• An emergency-management office wants scalable spoke routing on DMVPN without flooding IGP queries across every site. Why is BGP often chosen as the overlay routing protocol?
• County courts are migrating DMVPN IPsec protection from IKEv1 to IKEv2. What is a primary reason to prefer IKEv2 for modern crypto hygiene on the overlay?
• A city clerk’s office runs DMVPN over Internet transports and must encrypt mGRE overlay traffic. What mechanism binds that encryption to the tunnels?
• An airport authority hub must stop one chatty library spoke from consuming the entire hub uplink on a DMVPN WAN. Which QoS approach directly addresses that risk?
• A port authority builds Phase 3 DMVPN so branch spokes register to hub NHS addresses over the tunnel. What NHRP roles must the design assign for registration to succeed?
• A housing authority spoke stops registering to the DMVPN hub after the branch firewall’s NAT pool changes. What registration detail should engineers verify first?
• A sanitation department needs modular IKEv2 profiles that can cover both site-to-site branches and certain remote-access clients on the same crypto headend. Which approach best matches that requirement versus classic DMVPN Phase 3?
• A fire district standardizing future branch crypto VPNs wants reusable IKEv2 configuration blocks and less dependence on mGRE/NHRP for every new site type. When should the architects favor FlexVPN over classic DMVPN Phase 3?
• A police records bureau sees large civic GIS file transfers stall across DMVPN because IPsec-plus-GRE overhead shrinks effective path MTU. What tuning most directly addresses the symptom?
• A municipal hospital campus plans to add fifty volunteer-fire DMVPN spokes to existing hubs. What capacity concern should sizing review first?
• A community college district wants spoke routers to keep small routing tables while still reaching other campuses across DMVPN. What hub routing pattern best supports that goal?
• A regional planning commission does not want DMVPN spokes to carry full Internet tables. How should hubs steer general Internet-bound traffic from those spokes?
• A 911 PSAP runs DMVPN over dual underlays (MPLS and Internet) and must prefer MPLS when healthy. What design element correctly expresses that preference?
• An election office must ensure only approved site subnets are protected in the DMVPN IPsec SAs rather than encrypting unintended flows. What control should they apply carefully?