Cisco 350-501 Practice Test 6
Question 50
For an original SPCOR service-provider engineering scenario, consider: A metro router interface remains down after optics migration because transceiver support, modulation mode and line-system compatibility were never checked. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Compare optic part and platform matrix, channel power, error metrics and line-system span data on a controlled pair of links.
- Ignore optical attenuation and error counters because IP routing can always correct a fundamentally incompatible optical span.
- Check: Review span attenuation, termination equipment, optical power budget, splitter ratio and supported service rates in a documented link plan.
- Change: Validate coherent optic capabilities, router support, fiber reach and link optical telemetry before enabling routed optical connectivity.
- Change: Define the selected SR data plane and explicit policy segments, then verify headend steering, supported SIDs and actual egress path.
Explanation
Correct Answer
A:Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation. Acceptance: Routed optical ports establish stable links within their documented performance limits and exposed errors are monitored.
D:Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation. Evidence: Compare optic part and platform matrix, channel power, error metrics and line-system span data on a controlled pair of links.
Incorrect Answers
B:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation.
C:Check: Review span attenuation, termination equipment, optical power budget, splitter ratio and supported service rates in a documented link plan. Routed optical architectures integrate packet routing and optical transport interfaces but physical-layer impairments and equipment compatibility still constrain operation.
E:This option addresses a different service provider engineering topic (Segment routing architecture SRTE and SRv6) rather than the documented Routed optical network and pluggable coherent transport decision.
Question 51
A service provider network engineer is reviewing this backbone or customer-service scenario: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics. A proposed shortcut is: Treat IOS XE running-config commands as interchangeable with every IOS XR configuration transaction. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required.
- Treat IOS XE running-config commands as interchangeable with every IOS XR configuration transaction.
- Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
- Define the selected SR data plane and explicit policy segments, then verify headend steering, supported SIDs and actual egress path.
Explanation
Correct Answer
C:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics.
Incorrect Answers
A:Apply source validation or ACL policy at the correct ingress, coordinate RTBH only for approved attack targets and enable link-layer encryption where required. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
B:IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
D:Define the selected SR data plane and explicit policy segments, then verify headend steering, supported SIDs and actual egress path. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 52
A Cisco service provider design review finds: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics. The team proposes: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
- DWDM multiplexes wavelength channels over fiber while xPON shares passive optical distribution and DOCSIS and xDSL use distinct access media and systems.
- LPTS and CoPP protect route-processor traffic, while BGP TTL security and authentication restrict unauthorized control sessions when configured consistently.
- uRPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable.
Explanation
Correct Answer
A:Demonstrable success requires: Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state. This principle explains the proposed technical approach, which is: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
Incorrect Answers
B:DWDM multiplexes wavelength channels over fiber while xPON shares passive optical distribution and DOCSIS and xDSL use distinct access media and systems. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
C:LPTS and CoPP protect route-processor traffic, while BGP TTL security and authentication restrict unauthorized control sessions when configured consistently. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:URPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 53
The service provider operations team has not yet approved a change. Current evidence indicates: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Map each service endpoint, customer attachment, label-switched path and VPN policy against intended reachability using a two-tenant lab.
- Review span attenuation, termination equipment, optical power budget, splitter ratio and supported service rates in a documented link plan.
- Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device.
- Test spoofed and valid sources, check BGP blackhole policy scope and verify MACsec session status and counters on supported links.
Explanation
Correct Answer
C:If confirmed, the proportionate intervention is: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Applied case: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics.
Incorrect Answers
A:Map each service endpoint, customer attachment, label-switched path and VPN policy against intended reachability using a two-tenant lab. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
B:Review span attenuation, termination equipment, optical power budget, splitter ratio and supported service rates in a documented link plan. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:Test spoofed and valid sources, check BGP blackhole policy scope and verify MACsec session status and counters on supported links. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 54
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics. 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.
- Only intended tenant endpoints communicate and core forwarding provides the required transport without unwanted cross-customer bridging.
- Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state.
- Spoofed ingress traffic is denied, authorized flows remain, blackholing stays scoped and required Ethernet links are authenticated and encrypted.
- Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes.
Explanation
Correct Answer
B:The approved implementation step was: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Applied case: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics.
Incorrect Answers
A:Only intended tenant endpoints communicate and core forwarding provides the required transport without unwanted cross-customer bridging. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
C:Spoofed ingress traffic is denied, authorized flows remain, blackholing stays scoped and required Ethernet links are authenticated and encrypted. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:Real-time traffic receives policy-compliant treatment while untrusted markings cannot starve other paid service classes. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 55
An implementation sign-off request identifies the following problem: A provider deploys an IOS XR configuration using an IOS XE-only CLI syntax and assumes both software families share commit and rollback semantics. 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: 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.
- Change: Place each split RAN function and its xHaul link deliberately, enforcing the transport latency, timing and reliability needs for the selected functional split. Verify: Map RU DU CU interfaces, packet timing source, loss and delay budgets and measure behavior during a representative congestion window.
Explanation
Correct Answer
C:The change is successful only when: Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state.
Incorrect Answers
A:Change: Select and consistently implement the intended MPLS QoS tunneling model with explicit ingress classification and egress treatment. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
B:Change: Establish explicit QoS trust boundaries, bounded class marking and TE reservation policies that match measured capacity and the selected bandwidth model. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:This option addresses a different service provider engineering topic (5G vRAN and O-RAN xHaul transport) rather than the documented Cisco IOS XE and IOS XR software architecture decision.
Question 56
A service provider network engineer is reviewing this backbone or customer-service scenario: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation. A proposed shortcut is: Treat IOS XE running-config commands as interchangeable with every IOS XR configuration transaction. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
- Define the selected SR data plane and explicit policy segments, then verify headend steering, supported SIDs and actual egress path.
- Validate coherent optic capabilities, router support, fiber reach and link optical telemetry before enabling routed optical connectivity.
- Treat IOS XE running-config commands as interchangeable with every IOS XR configuration transaction.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
Incorrect Answers
B:Define the selected SR data plane and explicit policy segments, then verify headend steering, supported SIDs and actual egress path. An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
C:Validate coherent optic capabilities, router support, fiber reach and link optical telemetry before enabling routed optical connectivity. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model. Use this instead: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
Question 57
A Cisco service provider design review finds: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation. The team proposes: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- uRPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable.
- IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
- LPTS and CoPP protect route-processor traffic, while BGP TTL security and authentication restrict unauthorized control sessions when configured consistently.
- 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
B:Demonstrable success requires: Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state. Applied case: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
Incorrect Answers
A:URPF checks source reachability, RTBH can discard selected routed traffic during attacks and MACsec protects appropriate Ethernet links; none is interchangeable. An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
C:LPTS and CoPP protect route-processor traffic, while BGP TTL security and authentication restrict unauthorized control sessions when configured consistently. An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
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. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 58
The service provider operations team has not yet approved a change. Current evidence indicates: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
- Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device.
- Benchmark representative packet rates, CPU pinning or acceleration, virtual NIC queues, failure recovery and privilege boundaries.
- Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion.
Explanation
Correct Answer
B:If confirmed, the proportionate intervention is: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Applied case: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
Incorrect Answers
A:Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
C:Benchmark representative packet rates, CPU pinning or acceleration, virtual NIC queues, failure recovery and privilege boundaries. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:Capture customer DSCP, MPLS traffic class at ingress and transit, and egress queue or remark behavior under controlled congestion. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 59
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation. 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.
- Legitimate neighbors remain established and malicious control-plane floods cannot exhaust the router CPU at configured limits.
- Each access or backbone circuit uses compatible physical technology and operates within verified loss and throughput limits.
- Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state.
- Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another.
Explanation
Correct Answer
C:The approved implementation step was: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment. Applied case: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
Incorrect Answers
A:Legitimate neighbors remain established and malicious control-plane floods cannot exhaust the router CPU at configured limits. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
B:Each access or backbone circuit uses compatible physical technology and operates within verified loss and throughput limits. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:Marking and scheduling follow the selected model without unintended exposure of one customer's QoS assumptions to another. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
Question 60
For an original SPCOR service-provider engineering scenario, consider: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Change: Match the physical access or transport technology to the fiber plant, sharing model, reach and capacity requirements before choosing optics or termination equipment.
- Check: Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test.
- Check: Confirm exact software release, target command hierarchy, candidate diff, commit outcome and rollback in a lab device.
- Treat IOS XE running-config commands as interchangeable with every IOS XR configuration transaction.
- Change: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
Explanation
Correct Answer
C:Required intervention: Use the target OS configuration model and supported platform syntax, validating candidate changes and rollback behavior before deployment.
E:Acceptance: Changes are accepted only through supported platform mechanisms and an invalid candidate does not silently alter unrelated service state.
Incorrect Answers
A:Change: Match the physical access or transport technology to the fiber plant, sharing model, reach and capacity requirements before choosing optics or termination equipment. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
B:Check: Inspect received DSCP distributions, policer counters, class queue drops and reservation availability on a link saturation test. IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model.
D:IOS XE and IOS XR have distinct software architectures and management workflows; IOS XR supports a transactional configuration commit model. Applied case: An automation controller applies an unreviewed interface change on a service provider router without considering IOS XR candidate configuration and commit validation.
