Cisco CCNP 350-401 ENCOR Enterprise Architecture, High Availability, and QoS Design Practice Test 2

 

Topic 01 Practice Test 2 covers Enterprise Architecture, High Availability, and QoS Design for Cisco 350-401 ENCOR. For broader exam preparation, review the Cisco 350-401 ENCOR Exam Dumps. Every option includes focused technical reasoning explaining both the Cisco enterprise networking concept and its fit to the scenario.

Question 1

After an endpoint or service migration, a proposed change must simplify a medium site while retaining redundant aggregation for access switches. Which technology or configuration is the best match? Choose ONE.

1. DSCP EF marking
2. traffic policing
3. collapsed-core two-tier architecture
4. hierarchical QoS

Correct Answer(s)

 

C

Rationale

1. DSCP EF marking is intended for cases that must identify real-time voice packets so downstream QoS policies can place them in the expedited class. EF is the conventional DiffServ behavior used for low-loss, low-latency voice treatment. In this question collapsed-core two-tier architecture matches the requirement, whereas DSCP EF marking addresses a different need.
2. traffic policing helps when engineers need to stop one class from consuming more than its contracted share without adding queueing delay. drop or remark actions enforce the traffic contract at the measurement point. The stem instead depends on collapsed-core two-tier architecture; traffic policing therefore does not resolve the tested requirement.
3. collapsed-core two-tier architecture satisfies the scenario because a redundant aggregation pair can provide both policy boundary and backbone functions. Engineers must simplify a medium site while retaining redundant aggregation for access switches, and that need maps directly to this feature rather than the adjacent alternatives.
4. hierarchical QoS is used when engineers must shape an interface to a carrier rate and still prioritize voice within that shaped bandwidth. the parent can shape the aggregate while the child decides how classes use the shaped bandwidth. For this scenario, collapsed-core two-tier architecture is required; hierarchical QoS solves a different constraint.

 

Question 2

After a capacity threshold is reached, operations has one primary objective: expand data-center capacity by adding leaf switches without redesigning a hierarchical aggregation layer. Which option aligns most closely with that objective? Choose ONE.

1. StackWise Virtual pair
2. Weighted Random Early Detection (WRED)
3. low-latency queue (LLQ)
4. spine-leaf fabric

Correct Answer(s)

 

D

Rationale

1. StackWise Virtual pair applies when the goal is to dual-home an access switch to two distribution chassis while presenting one logical port-channel peer. the paired switches present a unified control and forwarding construct for supported multichassis links. This case calls for spine-leaf fabric; choosing StackWise Virtual pair would address another technical problem.
2. Weighted Random Early Detection (WRED) supports designs that need to reduce global TCP synchronization caused by many flows experiencing tail drop at once. WRED is congestion avoidance, unlike queuing mechanisms that only choose service order. Unlike spine-leaf fabric, Weighted Random Early Detection (WRED) misses the requirement that controls this scenario.
3. low-latency queue (LLQ) is used when engineers must give real-time packets priority service while still policing the priority class to prevent starvation. LLQ combines class-based queuing with a bounded priority class. For this scenario, spine-leaf fabric is required; low-latency queue (LLQ) solves a different constraint.
4. spine-leaf fabric should be selected because horizontal leaf growth preserves the fabric pattern and avoids a chokepoint aggregation tier. The requirement to expand data-center capacity by adding leaf switches without redesigning a hierarchical aggregation layer is central to the stem, and this option implements that behavior directly.

 

Question 3

After a dependency becomes unavailable, the team is comparing several technically valid features, but it specifically needs to contain Layer 2 failures within an access switch while allowing fast routed convergence upstream. Which choice is most appropriate? Choose ONE.

1. out-of-band management network
2. MQC class-map
3. class-based weighted fair queuing (CBWFQ)
4. routed access design

Correct Answer(s)

 

D

Rationale

1. out-of-band management network helps when engineers need to reach console or management interfaces even when the in-band campus path is unavailable. out-of-band access improves recoverability when in-band forwarding is the failure domain. The stem instead depends on routed access design; out-of-band management network therefore does not resolve the tested requirement.
2. MQC class-map is intended for cases that must reuse a named classification definition inside a modular QoS service policy. MQC classification is expressed in the class-map before policy-map behavior is selected. In this question routed access design matches the requirement, whereas MQC class-map addresses a different need.
3. class-based weighted fair queuing (CBWFQ) is useful for a requirement to guarantee a minimum share to business-critical data while allowing unused bandwidth to be shared. configured class bandwidth is enforced when congestion occurs and unused capacity can be shared. The needed choice is routed access design; class-based weighted fair queuing (CBWFQ) cannot satisfy the scenario’s decisive constraint.
4. routed access design satisfies the scenario because routing contains broadcast and STP failure domains at the access block. Engineers must contain Layer 2 failures within an access switch while allowing fast routed convergence upstream, and that need maps directly to this feature rather than the adjacent alternatives.

 

Question 4

After a security finding, a production constraint requires the environment to perform a supervisor failover while retaining synchronized platform state. Which option solves that requirement without addressing a different problem? Choose ONE.

1. ingress marking
2. traffic shaping
3. stateful supervisor switchover (SSO)
4. N+1 infrastructure redundancy

Correct Answer(s)

 

C

Rationale

1. ingress marking is used when engineers must apply policy as close as practical to the source so later queues can act on a stable marking. the edge has better endpoint context and can establish a trustworthy packet marking. For this scenario, stateful supervisor switchover (SSO) is required; ingress marking solves a different constraint.
2. traffic shaping helps when engineers need to limit a fast LAN-to-WAN egress to a provider rate without discarding every temporary burst. shaping delays excess packets in a queue instead of immediately dropping them. The stem instead depends on stateful supervisor switchover (SSO); traffic shaping therefore does not resolve the tested requirement.
3. stateful supervisor switchover (SSO) should be selected because sSO targets control-processor continuity rather than merely adding a second forwarding path. The requirement to perform a supervisor failover while retaining synchronized platform state is central to the stem, and this option implements that behavior directly.
4. N+1 infrastructure redundancy supports designs that need to tolerate one component failure while avoiding the expense of a fully duplicated 2N design. one additional unit covers a single failure without doubling every component. Unlike stateful supervisor switchover (SSO), N+1 infrastructure redundancy misses the requirement that controls this scenario.

 

Question 5

During a planned architecture review, the engineering team needs to reduce packet loss during a control-plane restart when neighboring routers support graceful restart. Which option most directly satisfies this requirement? Choose ONE.

1. traffic policing
2. three-tier campus architecture
3. hierarchical QoS
4. Nonstop Forwarding (NSF)

Correct Answer(s)

 

D

Rationale

1. traffic policing supports designs that need to stop one class from consuming more than its contracted share without adding queueing delay. drop or remark actions enforce the traffic contract at the measurement point. Unlike Nonstop Forwarding (NSF), traffic policing misses the requirement that controls this scenario.
2. three-tier campus architecture is useful for a requirement to keep distribution policy aggregation separate from a high-speed campus backbone. the design preserves separate access, policy aggregation, and backbone responsibilities. The needed choice is Nonstop Forwarding (NSF); three-tier campus architecture cannot satisfy the scenario’s decisive constraint.
3. hierarchical QoS applies when the goal is to combine an aggregate service-rate contract with differentiated treatment for traffic inside it. hierarchical policies model a provider rate at one level and per-class treatment at another. This case calls for Nonstop Forwarding (NSF); choosing hierarchical QoS would address another technical problem.
4. Nonstop Forwarding (NSF) is the direct choice because nSF complements stateful switchover by protecting traffic during routing recovery. The scenario requires the environment to reduce packet loss during a control-plane restart when neighboring routers support graceful restart, which is precisely the behavior this option provides.

 

Question 6

After a configuration audit, engineers must distribute routed flows across several equally preferred next hops. Which choice best addresses the decisive constraint? Choose ONE.

1. collapsed-core two-tier architecture
2. StackWise Virtual pair
3. equal-cost multipath (ECMP)
4. Weighted Random Early Detection (WRED)

Correct Answer(s)

 

C

Rationale

1. collapsed-core two-tier architecture helps when engineers need to simplify a medium site while retaining redundant aggregation for access switches. a redundant aggregation pair can provide both policy boundary and backbone functions. The stem instead depends on equal-cost multipath (ECMP); collapsed-core two-tier architecture therefore does not resolve the tested requirement.
2. StackWise Virtual pair is intended for cases that must dual-home an access switch to two distribution chassis while presenting one logical port-channel peer. the paired switches present a unified control and forwarding construct for supported multichassis links. In this question equal-cost multipath (ECMP) matches the requirement, whereas StackWise Virtual pair addresses a different need.
3. equal-cost multipath (ECMP) matches the requirement because parallel next hops provide both aggregate capacity and path redundancy. The team specifically needs to distribute routed flows across several equally preferred next hops; this option provides that behavior without depending on a different mechanism.
4. Weighted Random Early Detection (WRED) is useful for a requirement to reduce global TCP synchronization caused by many flows experiencing tail drop at once. WRED is congestion avoidance, unlike queuing mechanisms that only choose service order. The needed choice is equal-cost multipath (ECMP); Weighted Random Early Detection (WRED) cannot satisfy the scenario’s decisive constraint.

 

Question 7

After monitoring identifies an operational gap, the current design does not decide where DSCP or CoS values should become authoritative in the campus. What should the team implement to correct the design with the most direct fit? Choose ONE.

1. MQC class-map
2. out-of-band management network
3. QoS trust boundary
4. spine-leaf fabric

Correct Answer(s)

 

C

Rationale

1. MQC class-map is used when engineers must reuse a named classification definition inside a modular QoS service policy. MQC classification is expressed in the class-map before policy-map behavior is selected. For this scenario, QoS trust boundary is required; MQC class-map solves a different constraint.
2. out-of-band management network supports designs that need to reach console or management interfaces even when the in-band campus path is unavailable. out-of-band access improves recoverability when in-band forwarding is the failure domain. Unlike QoS trust boundary, out-of-band management network misses the requirement that controls this scenario.
3. QoS trust boundary is the direct choice because markings should be validated before they influence downstream queuing behavior. The scenario requires the environment to decide where DSCP or CoS values should become authoritative in the campus, which is precisely the behavior this option provides.
4. spine-leaf fabric applies when the goal is to support heavy east-west server traffic with consistent hop count across racks. every leaf reaches every spine, enabling ECMP and a consistent leaf-to-leaf path length. This case calls for QoS trust boundary; choosing spine-leaf fabric would address another technical problem.

 

Question 8

After a failover exercise, the requirement is to preserve a consistent network-layer marking for latency-sensitive RTP traffic across routed hops. Which approach should be selected? Choose ONE.

1. DSCP EF marking
2. routed access design
3. N+1 infrastructure redundancy
4. ingress marking

Correct Answer(s)

 

A

Rationale

802. DSCP EF marking matches the requirement because a Layer 3 DSCP value survives routed boundaries more naturally than an 802.1p-only tag. The team specifically needs to preserve a consistent network-layer marking for latency-sensitive RTP traffic across routed hops; this option provides that behavior without depending on a different mechanism.
803. routed access design is intended for cases that must contain Layer 2 failures within an access switch while allowing fast routed convergence upstream. routing contains broadcast and STP failure domains at the access block. In this question DSCP EF marking matches the requirement, whereas routed access design addresses a different need.
804. N+1 infrastructure redundancy is useful for a requirement to tolerate one component failure while avoiding the expense of a fully duplicated 2N design. one additional unit covers a single failure without doubling every component. The needed choice is DSCP EF marking; N+1 infrastructure redundancy cannot satisfy the scenario’s decisive constraint.
805. ingress marking applies when the goal is to normalize application markings once at the campus edge instead of reclassifying at every hop. classification near the source reduces repeated deep inspection throughout the path. This case calls for DSCP EF marking; choosing ingress marking would address another technical problem.

 

Question 9

After an application team reports intermittent behavior, a proposed change must give real-time packets priority service while still policing the priority class to prevent starvation. Which technology or configuration is the best match? Choose ONE.

1. hierarchical QoS
2. low-latency queue (LLQ)
3. three-tier campus architecture
4. stateful supervisor switchover (SSO)

Correct Answer(s)

 

B

Rationale

1. hierarchical QoS is intended for cases that must combine an aggregate service-rate contract with differentiated treatment for traffic inside it. hierarchical policies model a provider rate at one level and per-class treatment at another. In this question low-latency queue (LLQ) matches the requirement, whereas hierarchical QoS addresses a different need.
2. low-latency queue (LLQ) satisfies the scenario because lLQ combines class-based queuing with a bounded priority class. Engineers must give real-time packets priority service while still policing the priority class to prevent starvation, and that need maps directly to this feature rather than the adjacent alternatives.
3. three-tier campus architecture helps when engineers need to scale a multi-building campus without stretching access-layer failure domains into the core. distinct distribution blocks contain local failures while the core remains a fast transport layer. The stem instead depends on low-latency queue (LLQ); three-tier campus architecture therefore does not resolve the tested requirement.
4. stateful supervisor switchover (SSO) is used when engineers must increase chassis control-plane availability by maintaining an immediately usable standby supervisor. a hot standby supervisor reduces the disruption caused by a control-plane hardware failure. For this scenario, low-latency queue (LLQ) is required; stateful supervisor switchover (SSO) solves a different constraint.

 

Question 10

After a network refresh, operations has one primary objective: protect several non-real-time application classes from starvation on a congested link. Which option aligns most closely with that objective? Choose ONE.

1. class-based weighted fair queuing (CBWFQ)
2. StackWise Virtual pair
3. collapsed-core two-tier architecture
4. Nonstop Forwarding (NSF)

Correct Answer(s)

 

A

Rationale

1. class-based weighted fair queuing (CBWFQ) should be selected because cBWFQ is suited to differentiated data classes that need bandwidth assurance rather than minimal latency. The requirement to protect several non-real-time application classes from starvation on a congested link is central to the stem, and this option implements that behavior directly.
2. StackWise Virtual pair is used when engineers must dual-home an access switch to two distribution chassis while presenting one logical port-channel peer. the paired switches present a unified control and forwarding construct for supported multichassis links. For this scenario, class-based weighted fair queuing (CBWFQ) is required; StackWise Virtual pair solves a different constraint.
3. collapsed-core two-tier architecture supports designs that need to simplify a medium site while retaining redundant aggregation for access switches. a redundant aggregation pair can provide both policy boundary and backbone functions. Unlike class-based weighted fair queuing (CBWFQ), collapsed-core two-tier architecture misses the requirement that controls this scenario.
4. Nonstop Forwarding (NSF) applies when the goal is to preserve forwarding entries temporarily while routing protocols restore their sessions. graceful-restart cooperation lets neighbors retain routes while the restarting node recovers. This case calls for class-based weighted fair queuing (CBWFQ); choosing Nonstop Forwarding (NSF) would address another technical problem.

 

Question 11

After a service dependency is documented, the team is comparing several technically valid features, but it specifically needs to smooth bursty output so a downstream policer is less likely to drop packets. Which choice is most appropriate? Choose ONE.

1. spine-leaf fabric
2. equal-cost multipath (ECMP)
3. traffic shaping
4. out-of-band management network

Correct Answer(s)

 

C

Rationale

1. spine-leaf fabric is intended for cases that must support heavy east-west server traffic with consistent hop count across racks. every leaf reaches every spine, enabling ECMP and a consistent leaf-to-leaf path length. In this question traffic shaping matches the requirement, whereas spine-leaf fabric addresses a different need.
2. equal-cost multipath (ECMP) helps when engineers need to distribute routed flows across several equally preferred next hops. parallel next hops provide both aggregate capacity and path redundancy. The stem instead depends on traffic shaping; equal-cost multipath (ECMP) therefore does not resolve the tested requirement.
3. traffic shaping satisfies the scenario because the egress scheduler can pace traffic to the contracted rate and absorb temporary bursts. Engineers must smooth bursty output so a downstream policer is less likely to drop packets, and that need maps directly to this feature rather than the adjacent alternatives.
4. out-of-band management network is useful for a requirement to reach console or management interfaces even when the in-band campus path is unavailable. out-of-band access improves recoverability when in-band forwarding is the failure domain. The needed choice is traffic shaping; out-of-band management network cannot satisfy the scenario’s decisive constraint.

 

Question 12

After the operations team compares two designs, a production constraint requires the environment to stop one class from consuming more than its contracted share without adding queueing delay. Which option solves that requirement without addressing a different problem? Choose ONE.

1. traffic policing
2. QoS trust boundary
3. N+1 infrastructure redundancy
4. routed access design

Correct Answer(s)

 

A

Rationale

1. traffic policing should be selected because drop or remark actions enforce the traffic contract at the measurement point. The requirement to stop one class from consuming more than its contracted share without adding queueing delay is central to the stem, and this option implements that behavior directly.
2. QoS trust boundary supports designs that need to apply classification near the edge before congestion-sensitive traffic crosses shared links. an explicit trust boundary stops arbitrary endpoint tags from receiving preferential treatment. Unlike traffic policing, QoS trust boundary misses the requirement that controls this scenario.
3. N+1 infrastructure redundancy helps when engineers need to add one recoverable spare to a pool where any unit can substitute for one failed member. N+1 meets single-failure capacity goals at lower cost than complete 2N duplication. The stem instead depends on traffic policing; N+1 infrastructure redundancy therefore does not resolve the tested requirement.
4. routed access design is used when engineers must contain Layer 2 failures within an access switch while allowing fast routed convergence upstream. routing contains broadcast and STP failure domains at the access block. For this scenario, traffic policing is required; routed access design solves a different constraint.

 

Question 13

After a pilot exposes a design limitation, the engineering team needs to preferentially preserve higher-priority DSCP traffic while beginning early drops on lower classes. Which option most directly satisfies this requirement? Choose ONE.

1. Weighted Random Early Detection (WRED)
2. stateful supervisor switchover (SSO)
3. three-tier campus architecture
4. DSCP EF marking

Correct Answer(s)

 

A

Rationale

1. Weighted Random Early Detection (WRED) is the direct choice because different thresholds can make drop behavior sensitive to DSCP precedence. The scenario requires the environment to preferentially preserve higher-priority DSCP traffic while beginning early drops on lower classes, which is precisely the behavior this option provides.
2. stateful supervisor switchover (SSO) applies when the goal is to perform a supervisor failover while retaining synchronized platform state. SSO targets control-processor continuity rather than merely adding a second forwarding path. This case calls for Weighted Random Early Detection (WRED); choosing stateful supervisor switchover (SSO) would address another technical problem.
3. three-tier campus architecture supports designs that need to scale a multi-building campus without stretching access-layer failure domains into the core. distinct distribution blocks contain local failures while the core remains a fast transport layer. Unlike Weighted Random Early Detection (WRED), three-tier campus architecture misses the requirement that controls this scenario.
4. DSCP EF marking is useful for a requirement to identify real-time voice packets so downstream QoS policies can place them in the expedited class. EF is the conventional DiffServ behavior used for low-loss, low-latency voice treatment. The needed choice is Weighted Random Early Detection (WRED); DSCP EF marking cannot satisfy the scenario’s decisive constraint.

 

Question 14

After a policy exception is removed, engineers must reuse a named classification definition inside a modular QoS service policy. Which choice best addresses the decisive constraint? Choose ONE.

1. Nonstop Forwarding (NSF)
2. MQC class-map
3. collapsed-core two-tier architecture
4. low-latency queue (LLQ)

Correct Answer(s)

 

B

Rationale

1. Nonstop Forwarding (NSF) is intended for cases that must preserve forwarding entries temporarily while routing protocols restore their sessions. graceful-restart cooperation lets neighbors retain routes while the restarting node recovers. In this question MQC class-map matches the requirement, whereas Nonstop Forwarding (NSF) addresses a different need.
2. MQC class-map matches the requirement because mQC classification is expressed in the class-map before policy-map behavior is selected. The team specifically needs to reuse a named classification definition inside a modular QoS service policy; this option provides that behavior without depending on a different mechanism.
3. collapsed-core two-tier architecture is useful for a requirement to simplify a medium site while retaining redundant aggregation for access switches. a redundant aggregation pair can provide both policy boundary and backbone functions. The needed choice is MQC class-map; collapsed-core two-tier architecture cannot satisfy the scenario’s decisive constraint.
4. low-latency queue (LLQ) helps when engineers need to protect a small voice class from queueing delay on a congested WAN edge. strict priority service addresses delay and jitter when the link is congested. The stem instead depends on MQC class-map; low-latency queue (LLQ) therefore does not resolve the tested requirement.

 

Question 15

After a test workload exposes the bottleneck, the current design does not normalize application markings once at the campus edge instead of reclassifying at every hop. What should the team implement to correct the design with the most direct fit? Choose ONE.

1. spine-leaf fabric
2. ingress marking
3. equal-cost multipath (ECMP)
4. class-based weighted fair queuing (CBWFQ)

Correct Answer(s)

 

B

Rationale

1. spine-leaf fabric is used when engineers must support heavy east-west server traffic with consistent hop count across racks. every leaf reaches every spine, enabling ECMP and a consistent leaf-to-leaf path length. For this scenario, ingress marking is required; spine-leaf fabric solves a different constraint.
2. ingress marking is the direct choice because classification near the source reduces repeated deep inspection throughout the path. The scenario requires the environment to normalize application markings once at the campus edge instead of reclassifying at every hop, which is precisely the behavior this option provides.
3. equal-cost multipath (ECMP) supports designs that need to distribute routed flows across several equally preferred next hops. parallel next hops provide both aggregate capacity and path redundancy. Unlike ingress marking, equal-cost multipath (ECMP) misses the requirement that controls this scenario.
4. class-based weighted fair queuing (CBWFQ) applies when the goal is to assign differentiated bandwidth commitments among data classes without strict-priority treatment. weighted class queues provide predictable minimum service among competing applications. This case calls for ingress marking; choosing class-based weighted fair queuing (CBWFQ) would address another technical problem.

 

Question 16

After a route or policy change, the requirement is to apply class-level queuing beneath an overall tunnel or subinterface bandwidth cap. Which approach should be selected? Choose ONE.

1. QoS trust boundary
2. traffic shaping
3. routed access design
4. hierarchical QoS

Correct Answer(s)

 

D

Rationale

1. QoS trust boundary is useful for a requirement to apply classification near the edge before congestion-sensitive traffic crosses shared links. an explicit trust boundary stops arbitrary endpoint tags from receiving preferential treatment. The needed choice is hierarchical QoS; QoS trust boundary cannot satisfy the scenario’s decisive constraint.
2. traffic shaping is intended for cases that must limit a fast LAN-to-WAN egress to a provider rate without discarding every temporary burst. shaping delays excess packets in a queue instead of immediately dropping them. In this question hierarchical QoS matches the requirement, whereas traffic shaping addresses a different need.
3. routed access design applies when the goal is to avoid spanning-tree dependence across access-to-distribution uplinks and use equal-cost routed paths. Layer 3 access uplinks remove the campus uplinks from the spanning-tree topology. This case calls for hierarchical QoS; choosing routed access design would address another technical problem.
4. hierarchical QoS matches the requirement because a single flat policy cannot independently express both aggregate pacing and subordinate class scheduling as cleanly. The team specifically needs to apply class-level queuing beneath an overall tunnel or subinterface bandwidth cap; this option provides that behavior without depending on a different mechanism.

 

Question 17

After an outage postmortem, a proposed change must reduce first-hop and spanning-tree complexity by making a redundant distribution pair act as one logical switch. Which technology or configuration is the best match? Choose ONE.

1. DSCP EF marking
2. traffic policing
3. stateful supervisor switchover (SSO)
4. StackWise Virtual pair

Correct Answer(s)

 

D

Rationale

1. DSCP EF marking helps when engineers need to separate voice bearer traffic from default best-effort flows before a WAN bottleneck. consistent EF marking lets downstream queues recognize voice without reclassifying every flow. The stem instead depends on StackWise Virtual pair; DSCP EF marking therefore does not resolve the tested requirement.
2. traffic policing is used when engineers must stop one class from consuming more than its contracted share without adding queueing delay. drop or remark actions enforce the traffic contract at the measurement point. For this scenario, StackWise Virtual pair is required; traffic policing solves a different constraint.
3. stateful supervisor switchover (SSO) is intended for cases that must perform a supervisor failover while retaining synchronized platform state. SSO targets control-processor continuity rather than merely adding a second forwarding path. In this question StackWise Virtual pair matches the requirement, whereas stateful supervisor switchover (SSO) addresses a different need.
4. StackWise Virtual pair satisfies the scenario because logical switch virtualization lets a downstream channel span the two physical chassis. Engineers must reduce first-hop and spanning-tree complexity by making a redundant distribution pair act as one logical switch, and that need maps directly to this feature rather than the adjacent alternatives.

 

Question 18

After telemetry reveals uneven behavior, operations has one primary objective: separate infrastructure management traffic from user data for fault isolation and control. Which option aligns most closely with that objective? Choose ONE.

1. low-latency queue (LLQ)
2. out-of-band management network
3. Nonstop Forwarding (NSF)
4. Weighted Random Early Detection (WRED)

Correct Answer(s)

 

B

Rationale

1. low-latency queue (LLQ) supports designs that need to protect a small voice class from queueing delay on a congested WAN edge. strict priority service addresses delay and jitter when the link is congested. Unlike out-of-band management network, low-latency queue (LLQ) misses the requirement that controls this scenario.
2. out-of-band management network should be selected because management isolation limits dependence on the same data-plane components being repaired. The requirement to separate infrastructure management traffic from user data for fault isolation and control is central to the stem, and this option implements that behavior directly.
3. Nonstop Forwarding (NSF) is used when engineers must preserve forwarding entries temporarily while routing protocols restore their sessions. graceful-restart cooperation lets neighbors retain routes while the restarting node recovers. For this scenario, out-of-band management network is required; Nonstop Forwarding (NSF) solves a different constraint.
4. Weighted Random Early Detection (WRED) applies when the goal is to preferentially preserve higher-priority DSCP traffic while beginning early drops on lower classes. different thresholds can make drop behavior sensitive to DSCP precedence. This case calls for out-of-band management network; choosing Weighted Random Early Detection (WRED) would address another technical problem.

 

Question 19

After a lab validation, the team is comparing several technically valid features, but it specifically needs to maintain required service capacity after a single shared infrastructure component fails. Which choice is most appropriate? Choose ONE.

1. N+1 infrastructure redundancy
2. MQC class-map
3. equal-cost multipath (ECMP)
4. class-based weighted fair queuing (CBWFQ)

Correct Answer(s)

 

A

Rationale

1. N+1 infrastructure redundancy satisfies the scenario because the model is appropriate when pooled resources can share a common standby spare. Engineers must maintain required service capacity after a single shared infrastructure component fails, and that need maps directly to this feature rather than the adjacent alternatives.
2. MQC class-map helps when engineers need to match voice signaling by ACL or protocol attributes before assigning a QoS action. a class-map identifies which packets belong to a class; it does not itself schedule or police them. The stem instead depends on N+1 infrastructure redundancy; MQC class-map therefore does not resolve the tested requirement.
3. equal-cost multipath (ECMP) is useful for a requirement to distribute routed flows across several equally preferred next hops. parallel next hops provide both aggregate capacity and path redundancy. The needed choice is N+1 infrastructure redundancy; equal-cost multipath (ECMP) cannot satisfy the scenario’s decisive constraint.
4. class-based weighted fair queuing (CBWFQ) is intended for cases that must assign differentiated bandwidth commitments among data classes without strict-priority treatment. weighted class queues provide predictable minimum service among competing applications. In this question N+1 infrastructure redundancy matches the requirement, whereas class-based weighted fair queuing (CBWFQ) addresses a different need.

 

Question 20

After the team introduces redundancy, a production constraint requires the environment to keep distribution policy aggregation separate from a high-speed campus backbone. Which option solves that requirement without addressing a different problem? Choose ONE.

1. traffic shaping
2. three-tier campus architecture
3. ingress marking
4. QoS trust boundary

Correct Answer(s)

 

B

Rationale

1. traffic shaping is used when engineers must limit a fast LAN-to-WAN egress to a provider rate without discarding every temporary burst. shaping delays excess packets in a queue instead of immediately dropping them. For this scenario, three-tier campus architecture is required; traffic shaping solves a different constraint.
2. three-tier campus architecture should be selected because the design preserves separate access, policy aggregation, and backbone responsibilities. The requirement to keep distribution policy aggregation separate from a high-speed campus backbone is central to the stem, and this option implements that behavior directly.
3. ingress marking supports designs that need to normalize application markings once at the campus edge instead of reclassifying at every hop. classification near the source reduces repeated deep inspection throughout the path. Unlike three-tier campus architecture, ingress marking misses the requirement that controls this scenario.
4. QoS trust boundary helps when engineers need to decide where DSCP or CoS values should become authoritative in the campus. markings should be validated before they influence downstream queuing behavior. The stem instead depends on three-tier campus architecture; QoS trust boundary therefore does not resolve the tested requirement.

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