Network Services (20%)

ENSLD · 60 questions

• A regional hospital runs an eight-class enterprise QoS model with voice, video, clinical apps, and bulk backup, but its MPLS provider supports only four classes with DSCP-based ingress policing that re-marks out-of-profile traffic. Voice must stay priority and clinical apps must beat bulk backup after handoff. Which enterprise-to-provider mapping approach preserves intent across the WAN?
• A regional hospital campus supports 3,000 endpoints with voice, video, and data sharing a converged core, and ICU phones need low latency during congestion without tracking every call across the network. The design must scale simply as new clinics are added next year. Which QoS model should the designer select to meet the scalability requirement?
• A university campus supports 8,000 endpoints with voice, video and bulk data across many switches, and IT staff want scalable classification without per-flow signaling or reserved bandwidth on every hop. A small telepresence suite needs guaranteed admission in one building. Which QoS model choice best fits the campus-wide scale requirement?
• A regional bank streams market data via PIM sparse-mode to trading floors in three sites. During failover testing, a core router receives the same source packet on two interfaces and designers worry about a routing loop amplifying traffic. Which RPF check behavior should the designer validate to ensure loop-free multicast forwarding?
• A manufacturing firm uses six campus QoS classes for voice, interactive video, plant control, transactional data, bulk transfer, and scavenger traffic. Its new MPLS provider supports only a three-class model with fixed DSCP for real-time, business-critical, and default, and re-marks nonconforming values. The firm must keep voice latency low and protect control transactions without starving default. Which enterprise-to-SP DSCP aggregation strategy best preserves the end-to-end QoS policy intent?
• An enterprise video team reports duplicate multicast streams looping between two distribution routers during a PIM deployment with redundant paths. Engineers need loop-free forwarding without relying on TTL. Which RPF check behavior for multicast loop prevention should they validate in the design?
• A call center migrates to IP telephony with voice bearer, interactive video, transactional CRM and best-effort browsing sharing a congested WAN. The design must guarantee low latency for voice, assured forwarding for video and CRM, and fair treatment for browsing. Which PHB mapping meets those traffic-class requirements?
• A financial firm is redesigning management access for 150 branches where configuration backups cross the production WAN, auditors demand access during outages, and budget limits extra circuits. Which in-band versus out-of-band management trade-off best guides the design decision?
• A hospital network must support remote monitoring, configuration backup, and emergency access during a major routing outage that saturates production links. Clinical systems cannot tolerate management traffic competing with patient data, and auditors require isolated administrative paths for privileged access. Which network management design best meets resilience and isolation needs?
• A state university runs PIM sparse-mode for lecture capture across a main campus and two remote sites, needing automatic RP failover without manual config on every router and without depending on a single advertisement source. Which rendezvous point discovery design should the designer choose for resilient operation?
• A media company deploys PIM-SM across campus and WAN with many new groups weekly and no tolerance for single Auto-RP mapping failure. Engineers need dynamic discovery with resilience. Which rendezvous point discovery method using static, Auto-RP, or BSR best provides scalable redundancy?
• An insurance contact center runs voice, interactive video, call signaling, and bulk backup over a congested WAN, and agents complain of choppy audio during nightly backups. The design must protect voice latency, prioritize video, and relegate backups to leftover best-effort bandwidth. Which traffic-class to PHB mapping should the designer select to meet the QoS requirements?
• A 1200-user manufacturing campus connects Cisco phones with PCs daisy-chained behind them, plus guest laptops and printers in the same closets, and voice quality suffers when users copy large files. Which classification and marking approach establishes a correct trust boundary for end-to-end QoS?
• A hospital is redesigning management access for switches, wireless controllers and firewalls, must separate clinical traffic from management, restrict administrator access by role, and ensure management remains reachable during congestion or link failure. Which segmented management network and secure management plane design should be selected?
• A hospital campus deploys IP phones that mark voice with DSCP EF, user PCs daisy-chained through phones, and wireless guest traffic arriving at access switches. Nurses report choppy voice during backup windows and guest bursts. Which classification and marking design at the trust boundary best protects voice quality?
• A financial firm streams market data from two well-known sources to 500 trading desks. Requirements are one-to-many delivery without shared-tree complexity, receivers specify the exact source they want, and bandwidth is saved by dropping unwanted sources. Which multicast design supports explicit source selection by receivers?
• A seaport terminal operator runs 120 switches and routers across piers and warehouses on one campus core. Operations requires SSH and SNMP to stay reachable during a broadcast storm, syslog to never mix with cargo Wi-Fi, and TACACS+ authentication for all device logins. Which secure management plane design meets all three needs?
• A financial firm streams market data from a single well-known source to hundreds of trading desks that must explicitly request that source, with minimal RP setup and no shared-tree overhead. Receivers run modern stacks supporting source filtering. Which multicast design serves this source-specific multicast use case with IGMPv3?
• A regional office connects to an MPLS provider with a 100-Mbps contracted rate but a 1-Gbps physical handoff, and voice suffers drops during bursts while the provider discards out-of-profile traffic. Which WAN edge and handoff design controls bursts while preserving priority traffic?
• A hospital network carries life-critical monitoring alongside SNMP, syslog, and backup traffic, management sessions drop during congestion, and auditors require reliable device visibility at all times. Which QoS treatment for network management traffic ensures resilient monitoring?
• A global bank runs trader voice squawk boxes where every desk both sends and receives bursty group traffic, creating many senders, sparse receivers, and heavy source-registration churn with PIM-SM. How should bidirectional PIM be designed for this many-to-many application?
• A national broadcaster reports lost SNMP polls and delayed syslog during prime-time congestion on congested WAN edge links, while video contribution traffic dominates bandwidth and management sessions compete as best effort. Which design for prioritizing network management traffic with QoS restores reliable telemetry?
• A branch has a 200 Mbps Ethernet handoff but contracts a 50 Mbps MPLS CIR, and bulk file transfers are dropping interactive voice during peaks because excess traffic is discarded at the provider edge. Which shaping versus policing design at the WAN edge and provider handoff best protects voice?
• A university wants to deploy interactive virtual classrooms with hundreds of senders and receivers exchanging video across all campuses without heavy source-specific state. The design must minimize multicast state, avoid per-source trees, and use a shared root for all flows. Which PIM design best supports many-to-many communication?
• A university streams lectures in two PIM-SM domains joined over an inter-domain link, requiring local RP failover in each campus and shared active sources across domains without a single global RP. Which MSDP and anycast RP design supports RP redundancy and inter-domain sourcing?
• An enterprise video team streams quarterly town halls from one data-center source to 400 branch receivers, with sparse participation between events and a need for efficient paths during streams. PIM sparse mode with a rendezvous point is deployed. Which PIM sparse mode operation with source and shared trees should the designer describe to meet efficient delivery?
• A 500-seat contact center runs voice, video meetings, and bulk CRM sync over a 200-Mbps WAN that congests at quarter-end. Voice needs strict low delay, video needs guaranteed bandwidth without starving data, and TCP bulk traffic needs early drops before queues fill. Which queuing and congestion-avoidance combination should the designer specify for the WAN edge?
• A 2,000-seat contact center runs voice, agent video, and bulk data backups over a congested 1-Gbps WAN edge. Voice needs strict latency bounds, video needs guaranteed bandwidth, and backups must not starve during bursts. Which queuing and congestion-avoidance design meets the end-to-end QoS policy goal?
• A university runs PIM-SM in two campuses with separate RPs and needs RP redundancy inside each campus plus discovery of active multicast sources between campuses for inter-domain streaming. Failover must be automatic without static RP reconfiguration. Which RP redundancy and inter-domain design should the designer choose for this multicast requirement?
• A media company streams one-to-many 4K video to 500 branch receivers with bursty joins, needs shortest-path forwarding after discovery, and must limit initial flood. Which source-tree versus shared-tree PIM sparse-mode design best satisfies this multicast distribution requirement?
• A global enterprise with 500 sites needs voice, video, and bulk data treatment across a large MPLS core, with thousands of flows per second and no per-flow signaling overhead on core routers. A small telehealth pilot separately needs strict per-flow admission control. Which QoS model choice should the designer recommend for the large enterprise core to meet its scaling need?
• A service provider multicast network sees duplicate packets looping after a new link turned up, with PIM neighbors established on parallel paths toward the source. Which RPF-check multicast loop-prevention behavior best explains the correct forwarding decision on each router?
• An enterprise with an 8-class campus QoS model buys an MPLS VPN that offers only four provider classes with DSCP remarking at the PE. Voice must stay low-latency, video must not mix with bulk data, and markings must survive across the WAN. Which enterprise-to-provider mapping strategy should the designer specify for consistent end-to-end treatment?
• A global enterprise carries voice, video, and bulk data across a 500-site WAN needing scalable class-based treatment without per-flow setup, while two data-center clusters need guaranteed bandwidth for replication. Which DiffServ versus IntServ with RSVP design meets the scale properties?
• A regional health system marks voice, video, clinical apps, general data, and scavenger traffic internally, but its MPLS provider offers only strict-priority voice, business-critical, and default classes. Traffic must keep low latency for voice across the WAN without starving other apps. Which enterprise-to-provider QoS mapping preserves voice while fitting the provider class model?
• A financial campus uses PIM sparse mode for market data, but engineers see duplicate packets and intermittent loops after a unicast routing change altered path costs. Multicast now arrives on an unexpected router interface. Which RPF check behavior should the designer verify to restore loop-free forwarding?
• A 400-bed hospital needs to monitor switches and collect NetFlow during normal operations but must still reach device consoles when a core routing fault isolates production VLANs. Which management access design addresses in-band versus out-of-band trade-offs for this hospital network?
• A financial firm runs voice trading turrets, interactive video, transactional trading apps and bulk file replication over a congested WAN. Voice needs minimal delay and loss, video needs assured bandwidth, trading needs better-than-best-effort assurance, and replication can use spare capacity. Which PHB mapping strategy correctly reflects EF, AF, CS and default behavior?
• A university with mixed Cisco and third-party routers needs dynamic rendezvous point election across a new multivendor multicast core, with no manual RP addresses on every router and resilience if the primary candidate fails. Which rendezvous point discovery method supports multivendor dynamic election for this network?
• A 40-person startup manages six switches and two routers with no separate management cabling budget. The founder requires SSH and SNMP access to continue during normal operations while accepting that a major outage may block management, and wants minimal cost and complexity. Which network management access design best fits the budget and availability tradeoff?
• A hospital must prioritize voice, video consults, clinical signaling, and normal data across a congested WAN. Voice needs minimal delay, interactive video needs assured bandwidth, signaling needs preservation, and data uses remaining capacity. Which PHB mapping best meets this traffic-class requirement?
• A hospital is deploying PIM sparse mode across Cisco and non-Cisco switches, needs automatic RP failover without manual mapping on every router, and requires open-standards operation. Which rendezvous point discovery method should the multicast design specify?
• A university connects IP phones, lab PCs and guest kiosks through access switches to a distribution layer, with voice needing priority and guest traffic rate-limited. Markings from PCs and kiosks cannot be trusted, but phone markings can if verified. Which classification and marking approach at trust boundaries enforces this policy?
• A hospital must isolate device administration for switches, wireless controllers and firewalls after an audit found SSH open from patient Wi-Fi. The design needs role-based access, logged sessions, and reachability that survives a campus core link failure, with management traffic never mixed with clinical data. Which segmented management design best secures the management plane?
• A financial firm with separate trading and back-office VRFs must isolate SSH and SNMP access, enforce authentication, and log management changes to meet audit requirements. Which management plane design creates a segmented and secure management network for this firm?
• A sports league streams one 4K camera feed to thousands of receivers, must forward only from that known encoder, minimize RP state, and let receivers request the exact channel. Which multicast service design with host signaling best fits the single-source need?
• A media company streams CEO town halls from one known studio encoder to 5,000 wired desktops, wants shortest-path delivery without rendezvous point complexity, and endpoints support modern host signaling. Which source-specific multicast design with host signaling fits this one-to-many use case?
• A logistics firm runs headquarters plus 30 distribution centers over MPLS. Cisco phones on voice VLAN advertise via CDP, scanners and BYOD share data VLANs with random markings, and the provider honors only four DSCP classes on ingress. Which classification and marking design establishes correct trust boundaries for end-to-end QoS?
• A university runs interactive video collaboration with many senders and receivers in every building, with sparse participation per group and a need to minimize source-specific state in the core. RP load must stay balanced without registering each source. Which multicast design supports many-to-many delivery for this application?
• A 2000-site retail WAN runs SNMP polling, syslog, NetFlow and SSH over the same MPLS QoS profile as point-of-sale traffic. During congestion, polling timeouts and log gaps hide outages. Management must remain reachable without starving sales traffic. Which QoS design for network management traffic ensures reliable monitoring during congestion?
• A retailer polls 800 stores over a congested MPLS WAN where SNMP polls, syslog and NetFlow compete with point-of-sale traffic during peak hours and polls time out. Monitoring must stay reliable without starving sales traffic or taking priority over voice. Which QoS design for network management traffic best protects manageability during congestion?
• A branch connects with 100 Mbps Ethernet to a provider policing voice and data to a 50 Mbps contracted rate, with morning bursts dropping critical traffic at handoff. Which shaping versus policing design controls outbound bursts at the WAN edge handoff?
• A manufacturing campus runs a sensor collaboration app where 80 endpoints in multiple VLANs both send and receive the same multicast groups, creating many small flows. RP registration overhead and source-tree state must stay low. Which Bidirectional PIM design choice addresses the many-to-many requirement?
• A logistics firm has a 200 Mbps WAN edge handing off to a 100 Mbps provider policer for its hub site carrying voice, video, and bulk file transfers. Bursty file traffic causes provider drops and voice jitter during peaks. Which shaping versus policing design at the WAN edge and provider handoff best protects real-time traffic?
• A headquarters edge carries voice, video conferencing, and bulk backup sharing a congested 200 Mbps link with TCP starvation during backups. Which queuing and congestion avoidance design protects real-time traffic while keeping TCP efficient?
• A media company streams a CEO broadcast from one encoder to 500 branch receivers with sparse membership, plus a few dense trading-floor feeds needing shortest-path delivery. Bandwidth and join latency matter. Which multicast design using source versus shared trees and PIM sparse mode fits these flows?
• A media firm streams live events to two data centers with Anycast RP inside each site and needs RP redundancy plus shared active sources between sites for fast failover without a single point of failure. PIM domains must stay interconnected. Which design provides RP redundancy with inter-domain source sharing?
• A global enterprise runs PIM-SM in two regions with separate RPs, needing RP redundancy inside each region and shared group sources across regions without single-point failure. Interdomain source discovery must remain loop-free. Which MSDP with anycast RP design meets the redundancy requirement?
• A campus WAN edge carries voice, interactive video, and bulk data with recurring congestion at peak hours causing voice choppiness and video freezes while bulk transfers fill buffers. Which queuing and congestion-avoidance design best protects real-time media while fairly sharing remaining bandwidth?
• A media enterprise streams studio video to 200 receivers across a PIM sparse-mode campus where most groups have few active sources and RP load is rising, and engineers debate shared-tree efficiency versus optimal paths. Which source-tree versus shared-tree and PIM sparse-mode operation best balances RP load and path optimality?