Cisco 350-501 Practice Test 60
Question 590
For an original SPCOR service-provider engineering scenario, consider: A customer repeatedly exceeds contracted ingress bandwidth and a carrier applies only outbound shaping, leaving the oversubscribed ingress queue vulnerable to bursts. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
- Grant every packet unbounded strict priority and assume congestion never causes class starvation or SLA violation.
- Change: Classify at the chosen trust point and apply appropriate bounded priority, policing, shaping and congestion avoidance according to SLA and measured flow behavior.
- Check: Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream.
- Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability.
Explanation
Correct Answer
A:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. Acceptance: High-priority services meet policy while excess traffic is bounded and ordinary customer classes retain their contracted forwarding share.
C:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. Evidence: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
Incorrect Answers
B:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
D:Check: Inspect (*,G) and (S,G) state, RP mapping, RPF interface and actual receiver joins under a test stream. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
E:Change: Define separate VRFs with correct route distinguishers and coordinated route-target import and export policies and confirm PE-to-PE labeled reachability. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Question 591
A service provider network engineer is reviewing this backbone or customer-service scenario: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion. A proposed shortcut is: Grant every packet unbounded strict priority and assume congestion never causes class starvation or SLA violation. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Classify at the chosen trust point and apply appropriate bounded priority, policing, shaping and congestion avoidance according to SLA and measured flow behavior.
- Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure.
- Grant every packet unbounded strict priority and assume congestion never causes class starvation or SLA violation.
- Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Incorrect Answers
B:Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
C:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. Use this instead: Classify at the chosen trust point and apply appropriate bounded priority, policing, shaping and congestion avoidance according to SLA and measured flow behavior.
D:Use matching IGMP or MLD listener protocols and supported source-filtering behavior on the appropriate IPv4 or IPv6 access segment. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Question 592
A Cisco service provider design review finds: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion. The team proposes: Classify at the chosen trust point and apply appropriate bounded priority, policing, shaping and congestion avoidance according to SLA and measured flow behavior. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network.
- E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions.
- A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information.
- Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Explanation
Correct Answer
D:Relevant validation before approval: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion. Demonstrable success requires: High-priority services meet policy while excess traffic is bounded and ordinary customer classes retain their contracted forwarding share.
Incorrect Answers
A:IEEE 802.1ad provider bridging adds a service tag outside customer VLAN tags, and tag roles must remain consistent through the carrier network. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
B:E-Line is point-to-point, E-LAN is multipoint and E-Tree distinguishes root and leaf connectivity, requiring deliberate forwarding restrictions. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
C:A route distinguisher makes overlapping VPN routes uniquely identifiable, whereas route targets control membership and distribution of VPN routing information. A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion.
Question 593
The service provider operations team has not yet approved a change. Current evidence indicates: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC.
- Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants.
- Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
- Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
Explanation
Correct Answer
D:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. Confirm afterward that: High-priority services meet policy while excess traffic is bounded and ordinary customer classes retain their contracted forwarding share.
Incorrect Answers
A:Map UNI endpoints and approved source-destination pairs, then test leaf-to-leaf and root-to-leaf reachability in the staged EVC. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
B:Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
C:Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Question 594
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion. 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.
- Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports.
- High-priority services meet policy while excess traffic is bounded and ordinary customer classes retain their contracted forwarding share.
- The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops.
- Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances.
Explanation
Correct Answer
B:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. Applied case: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion.
Incorrect Answers
A:Subscribers receive only authorized group and source traffic with no unnecessary replication to idle access ports. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
C:The dual-homed customer retains connectivity with correct single-copy flooding and no persistent Layer-2 forwarding loops. A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion.
D:Customer MACs or prefixes resolve to the appropriate remote PE without leaking between unrelated EVPN instances. A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion.
Question 595
An implementation sign-off request identifies the following problem: A provider uses an absolute priority queue for all traffic classes and sees starvation of business-critical best-effort flows during customer congestion. Which paired technical change and validation should close the implementation review? Select ONE best answer.
- Change: Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure. Verify: Inspect ring protection state, OAM continuity-check results, link-failure events and convergence on one forced-ring break.
- Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths. Verify: Compare imported RT lists, VRF next hops, shared service return routing and firewall policy using two customer tenants.
- Change: Classify at the chosen trust point and apply appropriate bounded priority, policing, shaping and congestion avoidance according to SLA and measured flow behavior. Verify: Check class-map matches, DSCP or MPLS TC, policer violations, shaping queue depth, WRED counters and customer throughput during controlled congestion.
- Change: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping. Verify: Capture ingress and egress Ethernet frames including TPID, tag stack and VLAN IDs for two isolated customers.
Explanation
Correct Answer
C:Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load. The change is successful only when: High-priority services meet policy while excess traffic is bounded and ordinary customer classes retain their contracted forwarding share.
Incorrect Answers
A:Change: Enable supported ring protection and Ethernet OAM mechanisms to enforce a loop-free normal state and verify service continuity after failure. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
B:Change: Build selective route leaking or shared-service VRF connectivity with scoped route targets and explicit security controls for shared and internet paths. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
D:Change: Configure consistent service and customer VLAN tag handling with explicit encapsulation and correct cross-PE mapping. Policing can drop or remark out-of-profile traffic, shaping buffers and paces egress, and weighted congestion avoidance can reduce tail-drop pressure under load.
Question 596
A service provider network engineer is reviewing this backbone or customer-service scenario: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules. A proposed shortcut is: Guess interface leaf names from screenshots and treat every numeric YANG value as an unvalidated free-form string. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Keep state in an access-controlled locked backend and review plans and drift against provider-supported network resources before apply.
- Align exporter and collector template handling, source interface, sampling and timeout settings, then validate interpreted flow fields.
- Use the platform's published YANG module and typed hierarchical schema to construct data operations with validated paths and leaf types.
- Guess interface leaf names from screenshots and treat every numeric YANG value as an unvalidated free-form string.
Explanation
Correct Answer
C:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. The required acceptance condition is: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes.
Incorrect Answers
A:Keep state in an access-controlled locked backend and review plans and drift against provider-supported network resources before apply. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
B:Align exporter and collector template handling, source interface, sampling and timeout settings, then validate interpreted flow fields. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
D:YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
Question 597
A Cisco service provider design review finds: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules. The team proposes: Use the platform's published YANG module and typed hierarchical schema to construct data operations with validated paths and leaf types. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- SNMPv3 security models can provide authenticated and private management traffic; v2c communities do not themselves encrypt or strongly authenticate messages.
- NetFlow and IPFIX export summarized flow records whose field templates and sampling rules determine what collectors can reconstruct.
- YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
- NETCONF uses modeled XML RPC messages and datastore operations; an active SSH transport or accepted candidate does not necessarily mean a committed change.
Explanation
Correct Answer
C:Demonstrable success requires: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes. This principle explains the proposed technical approach, which is: Use the platform's published YANG module and typed hierarchical schema to construct data operations with validated paths and leaf types.
Incorrect Answers
A:SNMPv3 security models can provide authenticated and private management traffic; v2c communities do not themselves encrypt or strongly authenticate messages. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
B:NetFlow and IPFIX export summarized flow records whose field templates and sampling rules determine what collectors can reconstruct. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
D:NETCONF uses modeled XML RPC messages and datastore operations; an active SSH transport or accepted candidate does not necessarily mean a committed change. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
Question 598
The service provider operations team has not yet approved a change. Current evidence indicates: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Compare NETCONF hello capabilities, target datastore, rpc-reply ok or rpc-error and device running configuration after a staged edit.
- Check state addresses, lock contention, plan create-update-destroy actions and expected controller changes in a sandbox.
- Inspect capabilities, URL module prefix, requested HTTP method, Content-Type and returned status with a nonproduction test interface.
- Inspect module revision, namespace, leaf types and schema paths and test one valid and one invalid payload in a lab.
Explanation
Correct Answer
D:Confirm afterward that: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes. Applied case: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules.
Incorrect Answers
A:Compare NETCONF hello capabilities, target datastore, rpc-reply ok or rpc-error and device running configuration after a staged edit. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
B:Check state addresses, lock contention, plan create-update-destroy actions and expected controller changes in a sandbox. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
C:Inspect capabilities, URL module prefix, requested HTTP method, Content-Type and returned status with a nonproduction test interface. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
Question 599
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules. 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 authorized PEs are targeted, repeated runs become stable and skipped or unreachable devices are explicitly reported.
- Approved collectors can query counters securely and unauthorized requests fail while essential traps remain observable.
- Read and write requests affect only approved modeled resources and invalid payloads receive specific diagnosable errors.
- Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes.
Explanation
Correct Answer
D:YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Only authorized PEs are targeted, repeated runs become stable and skipped or unreachable devices are explicitly reported. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
B:Approved collectors can query counters securely and unauthorized requests fail while essential traps remain observable. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
C:Read and write requests affect only approved modeled resources and invalid payloads receive specific diagnosable errors. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
Question 600
For an original SPCOR service-provider engineering scenario, consider: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules. Select THREE compatible elements: a proper correction, a targeted diagnostic and an acceptance result.
- Result: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes.
- Check: Inspect capabilities, URL module prefix, requested HTTP method, Content-Type and returned status with a nonproduction test interface.
- Change: Use the platform's published YANG module and typed hierarchical schema to construct data operations with validated paths and leaf types.
- Result: Approved collectors can query counters securely and unauthorized requests fail while essential traps remain observable.
- Check: Inspect module revision, namespace, leaf types and schema paths and test one valid and one invalid payload in a lab.
- Change: Align exporter and collector template handling, source interface, sampling and timeout settings, then validate interpreted flow fields.
Explanation
Correct Answer
A:YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts. Applied case: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules.
C:Acceptance: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes. Applied case: A service provider publishes network configuration in ad hoc JSON with an interface speed as arbitrary text and no machine-readable validity rules.
E:Acceptance: Model-compliant requests accept correct data and reject wrong leaf paths or types without unintended configuration changes. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
Incorrect Answers
B:Check: Inspect capabilities, URL module prefix, requested HTTP method, Content-Type and returned status with a nonproduction test interface. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
D:Result: Approved collectors can query counters securely and unauthorized requests fail while essential traps remain observable. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
F:Change: Align exporter and collector template handling, source interface, sampling and timeout settings, then validate interpreted flow fields. YANG defines containers lists keys and typed leaves, allowing supported protocol clients to validate configuration independently of arbitrary CLI text layouts.
