Cisco 350-501 Practice Test 9
Question 80
For an original SPCOR service-provider engineering scenario, consider: A backbone deploys a short-pipe treatment but mistakenly trusts provider internal MPLS traffic class markings for customer-facing egress scheduling. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Assume MPLS traffic-class and customer IP markings always copy bidirectionally regardless of the chosen tunneling model.
- Change: Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment.
- Check: Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links.
- Check: Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion.
- Change: Size and isolate NFVI compute, networking and storage resources for each VNF or container workload and validate orchestration and availability.
Explanation
Correct Answer
B:Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior. Acceptance: Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another.
D:Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior. Required intervention: Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment.
Incorrect Answers
A:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior.
C:Check: Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links. Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior.
E:Change: Size and isolate NFVI compute, networking and storage resources for each VNF or container workload and validate orchestration and availability. Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior.
Question 81
A service provider network engineer is reviewing this backbone or customer-service scenario: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing. A proposed shortcut is: Trust every customer high-priority packet and guarantee zero queue loss regardless of physical bandwidth and TE constraints. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model.
- Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required.
- Trust every customer high-priority packet and guarantee zero queue loss regardless of physical bandwidth and TE constraints.
- Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing.
Incorrect Answers
B:Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
C:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
D:Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 82
A Cisco service provider design review finds: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing. The team proposes: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- LPTS and CoPP protect route-processor traffic, while BGP TTL security and authentication restrict unauthorized control sessions when configured consistently.
- 5G RAN functional splits determine where RU DU and CU processing occurs; their transport interfaces have distinct capacity, timing and latency requirements.
- IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
- Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Explanation
Correct Answer
D:Demonstrable success requires: Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes. Applied case: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing.
Incorrect Answers
A:This option addresses a different service provider engineering topic (Control plane policing LPTS and BGP TTL security) rather than the documented Traffic engineering and interdomain QoS trust boundaries decision.
B:5G RAN functional splits determine where RU DU and CU processing occurs; their transport interfaces have distinct capacity, timing and latency requirements. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
C:IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 83
The service provider operations team has not yet approved a change. Current evidence indicates: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links.
- Map RU DU CU interfaces, packet timing source, loss and delay budgets and measure behavior during a representative congestion window.
- Test spoofed and valid sources, check BGP blackhole policy scope and verify MACsec session status and counters on supported links.
- Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
Explanation
Correct Answer
D:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. Applied case: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing.
Incorrect Answers
A:Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
B:Map RU DU CU interfaces, packet timing source, loss and delay budgets and measure behavior during a representative congestion window. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
C:Test spoofed and valid sources, check BGP blackhole policy scope and verify MACsec session status and counters on supported links. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 84
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing. The carrier operations owner needs positive and negative tests showing existing customer services remain available. Which acceptance result demonstrates correct service provider forwarding and control behavior without disrupting authorized workflows? Select ONE best answer.
- Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
- Functional units exchange traffic over the correct xHaul links within approved performance budgets during normal and impaired operation.
- Routed optical ports establish stable links within their documented performance limits and exposed errors are monitored.
- Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another.
Explanation
Correct Answer
A:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. The result must be validated using the documented device, service or access context.
Incorrect Answers
B:Functional units exchange traffic over the correct xHaul links within approved performance budgets during normal and impaired operation. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
C:Routed optical ports establish stable links within their documented performance limits and exposed errors are monitored. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
D:Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 85
An implementation sign-off request identifies the following problem: An enterprise customer marks every packet as expedited forwarding and saturates a shared carrier priority queue because the provider accepts the marking without policing. Which paired technical change and validation should close the implementation review? Select ONE best answer.
- Change: Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment. Verify: Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion.
- Change: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model. Verify: Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
- Change: Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required. Verify: Test spoofed and valid sources, check BGP blackhole policy scope and verify MACsec session status and counters on supported links.
- Change: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Verify: Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device.
Explanation
Correct Answer
B:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. The change is successful only when: Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
Incorrect Answers
A:Change: Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
C:Change: Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
D:Change: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 86
A service provider network engineer is reviewing this backbone or customer-service scenario: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes. A proposed shortcut is: Trust every customer high-priority packet and guarantee zero queue loss regardless of physical bandwidth and TE constraints. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model.
- Trust every customer high-priority packet and guarantee zero queue loss regardless of physical bandwidth and TE constraints.
- Place each split RAN function and its xHaul link deliberately, enforcing the transport latency, timing and reliability needs for the selected functional split.
- Size and isolate NFVI compute, networking and storage resources for each VNF or container workload and validate orchestration and availability.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
Incorrect Answers
B:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. Applied case: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
C:Place each split RAN function and its xHaul link deliberately, enforcing the transport latency, timing and reliability needs for the selected functional split. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
D:Size and isolate NFVI compute, networking and storage resources for each VNF or container workload and validate orchestration and availability. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 87
A Cisco service provider design review finds: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes. The team proposes: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation.
- Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior.
- Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
- uRPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable.
Explanation
Correct Answer
C:Demonstrable success requires: Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes. Applied case: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
Incorrect Answers
A:Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
B:Uniform propagates QoS semantics end to end while pipe and short-pipe separate provider tunnel treatment from customer traffic with different egress behavior. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
D:URPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 88
The service provider operations team has not yet approved a change. Current evidence indicates: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion.
- Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links.
- Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
- Benchmark representative packet rates, CPU pinning or acceleration, virtual NIC queues, failure recovery and privilege boundaries.
Explanation
Correct Answer
C:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. Confirm afterward that: Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
Incorrect Answers
A:Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
B:Examine IGP SID advertisement, SR policy candidate path, segment list and traceroute or telemetry for both normal and failed links. A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
D:Benchmark representative packet rates, CPU pinning or acceleration, virtual NIC queues, failure recovery and privilege boundaries. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 89
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes. The carrier operations owner needs positive and negative tests showing existing customer services remain available. Which acceptance result demonstrates correct service provider forwarding and control behavior without disrupting authorized workflows? Select ONE best answer.
- Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another.
- Only intended tenant endpoints communicate and core forwarding provides the required transport without unwanted cross-customer bridging.
- Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
- Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state.
Explanation
Correct Answer
C:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. The approved implementation step was: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model.
Incorrect Answers
A:Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another. A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
B:This option addresses a different service provider engineering topic (Metro Ethernet and MPLS core architecture) rather than the documented Traffic engineering and interdomain QoS trust boundaries decision.
D:Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
Question 90
For an original SPCOR service-provider engineering scenario, consider: A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
- Change: Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required.
- Change: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model.
- Check: Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device.
- Trust every customer high-priority packet and guarantee zero queue loss regardless of physical bandwidth and TE constraints.
Explanation
Correct Answer
A:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. Acceptance: Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
C:Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected. Evidence: Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
Incorrect Answers
B:Change: Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required. A backbone reserves bandwidth for traffic-engineered flows but fails to check that the selected constraint model permits overlapping reservation across service classes.
D:Check: Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
E:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. Service provider QoS must enforce customer trust and admission limits; DS-TE reservation models affect how traffic-class bandwidth can be shared or protected.
