Cisco 350-501 Practice Test 12
Question 110
For an original SPCOR service-provider engineering scenario, consider: Two P routers have matching IPv4 reachability but their IS-IS hello packets show mismatched Level capabilities, preventing the expected adjacency. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Check: Check neighbor state transitions, interface MTU, hello and dead intervals, area type and network type on both peers.
- Configure unrelated IP static routes and assume IS-IS must establish even when its interface hellos are incompatible.
- Change: Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link.
- Change: Apply supported consistent metric style and tune link costs to the provider's intended shortest-path and capacity policy.
- Check: Inspect IS-IS neighbor state, hello capture, interface MTU and level configuration at both endpoints.
Explanation
Correct Answer
C:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. Acceptance: The intended Level-1 or Level-2 adjacency forms and the routers exchange consistent link-state information without dropping required hello traffic.
E:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. Required intervention: Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link.
Incorrect Answers
A:Check: Check neighbor state transitions, interface MTU, hello and dead intervals, area type and network type on both peers. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
B:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
D:Change: Apply supported consistent metric style and tune link costs to the provider's intended shortest-path and capacity policy. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
Question 111
A service provider network engineer is reviewing this backbone or customer-service scenario: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree. A proposed shortcut is: Configure unrelated IP static routes and assume IS-IS must establish even when its interface hellos are incompatible. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link.
- Select single- or multi-topology IS-IS according to dual-stack forwarding requirements and verify both address-family reachability and advertised topology data.
- Coordinate BFD with supported routing clients and realistic detect-multiplier and interval settings for stable rapid failure detection.
- Configure unrelated IP static routes and assume IS-IS must establish even when its interface hellos are incompatible.
Explanation
Correct Answer
A:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree.
Incorrect Answers
B:Select single- or multi-topology IS-IS according to dual-stack forwarding requirements and verify both address-family reachability and advertised topology data. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
C:Coordinate BFD with supported routing clients and realistic detect-multiplier and interval settings for stable rapid failure detection. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
D:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. Applied case: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree.
Question 112
A Cisco service provider design review finds: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree. The team proposes: Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
- Redistribution changes protocol scope and metrics; uncontrolled mutual redistribution can create loops and excessive IGP state.
- MED influences comparisons under specific BGP decision contexts, and AS_PATH prepending is advisory because remote networks may apply their own preferences.
- BGP best-path selection considers local policy such as weight and local preference before several later tie breakers, including path length and MED context.
Explanation
Correct Answer
A:Demonstrable success requires: The intended Level-1 or Level-2 adjacency forms and the routers exchange consistent link-state information without dropping required hello traffic. Applied case: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree.
Incorrect Answers
B:Redistribution changes protocol scope and metrics; uncontrolled mutual redistribution can create loops and excessive IGP state. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
C:MED influences comparisons under specific BGP decision contexts, and AS_PATH prepending is advisory because remote networks may apply their own preferences. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
D:BGP best-path selection considers local policy such as weight and local preference before several later tie breakers, including path length and MED context. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
Question 113
The service provider operations team has not yet approved a change. Current evidence indicates: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Check neighbor state transitions, interface MTU, hello and dead intervals, area type and network type on both peers.
- Inspect IS-IS neighbor state, hello capture, interface MTU and level configuration at both endpoints.
- Evaluate a test table with allowed, denied and boundary prefixes against actual show-policy and BGP advertised-routes evidence.
- Record each link cost and LSDB view, calculate expected shortest paths and compare route changes during shut and no-shut tests.
Explanation
Correct Answer
B:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. Confirm afterward that: The intended Level-1 or Level-2 adjacency forms and the routers exchange consistent link-state information without dropping required hello traffic.
Incorrect Answers
A:Check neighbor state transitions, interface MTU, hello and dead intervals, area type and network type on both peers. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
C:Evaluate a test table with allowed, denied and boundary prefixes against actual show-policy and BGP advertised-routes evidence. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
D:Record each link cost and LSDB view, calculate expected shortest paths and compare route changes during shut and no-shut tests. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
Question 114
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree. 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.
- Failure recovery stays within service limits and no stale unvalidated forwarding state persists beyond documented timers.
- Accepted members forward correctly, aggregate capacity reflects active links and service survives an individual member failure.
- Genuine path loss is detected promptly while minor delay variation does not trigger avoidable adjacency resets.
- The intended Level-1 or Level-2 adjacency forms and the routers exchange consistent link-state information without dropping required hello traffic.
Explanation
Correct Answer
D:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. The approved implementation step was: Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link.
Incorrect Answers
A:Failure recovery stays within service limits and no stale unvalidated forwarding state persists beyond documented timers. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
B:Accepted members forward correctly, aggregate capacity reflects active links and service survives an individual member failure. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
C:Genuine path loss is detected promptly while minor delay variation does not trigger avoidable adjacency resets. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
Question 115
An implementation sign-off request identifies the following problem: A new core router has IS-IS enabled on a link but no neighbor forms because the interface MTU and supported hello padding behavior disagree. Which paired technical change and validation should close the implementation review? Select ONE best answer.
- Change: Choose documented BGP ingress-traffic engineering signals and verify how relevant peers actually compare received alternatives. Verify: Examine advertised route attributes per peer, remote looking-glass paths and measured ingress flows before and after the change.
- Change: Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops. Verify: Check route-reflector client relationships, originator and cluster attributes, BGP next-hop resolution and the RIB versus FIB.
- Change: Match IS-IS level operation and interface parameters before expecting LSP exchange and route installation across a service provider core link. Verify: Inspect IS-IS neighbor state, hello capture, interface MTU and level configuration at both endpoints.
- Change: Apply documented BGP community or extended-community policies at the intended import or export point and verify resulting attribute propagation. Verify: Check received and advertised BGP attributes, applied route policy, peer documentation and resulting best path for a controlled test prefix.
Explanation
Correct Answer
C:IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor. The change is successful only when: The intended Level-1 or Level-2 adjacency forms and the routers exchange consistent link-state information without dropping required hello traffic.
Incorrect Answers
A:Change: Choose documented BGP ingress-traffic engineering signals and verify how relevant peers actually compare received alternatives. IS-IS adjacencies use link-local protocol hellos and compatible level, circuit and network settings; IP reachability alone does not create a neighbor.
B:Change: Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops.
D:Change: Apply documented BGP community or extended-community policies at the intended import or export point and verify resulting attribute propagation.
Question 116
A service provider network engineer is reviewing this backbone or customer-service scenario: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency. A proposed shortcut is: Duplicate router system IDs to force adjacency and use mismatched Level-1 area addresses as a substitute for a backbone design. What should the service provider engineer recommend as the narrowly scoped correction? Select ONE best answer.
- Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops.
- Apply documented BGP community or extended-community policies at the intended import or export point and verify resulting attribute propagation.
- Duplicate router system IDs to force adjacency and use mismatched Level-1 area addresses as a substitute for a backbone design.
- Assign unique IS-IS system IDs and consistent area identifiers for Level-1 adjacency, with proper Level-2 reachability across areas.
Explanation
Correct Answer
D:This targeted action addresses the observed service-provider control or forwarding gap without discarding necessary controls. Applied case: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency.
Incorrect Answers
A:Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
B:Apply documented BGP community or extended-community policies at the intended import or export point and verify resulting attribute propagation. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
C:IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability. For this best change assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it.
Question 117
A Cisco service provider design review finds: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency. The team proposes: Assign unique IS-IS system IDs and consistent area identifiers for Level-1 adjacency, with proper Level-2 reachability across areas. Which engineering principle most strongly supports the recommended response? Select ONE best answer.
- BGP best-path selection considers local policy such as weight and local preference before several later tie breakers, including path length and MED context.
- Redistribution changes protocol scope and metrics; uncontrolled mutual redistribution can create loops and excessive IGP state.
- IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
- Single topology shares reachability assumptions across enabled families, while multi-topology can maintain distinct IPv4 and IPv6 topology information.
Explanation
Correct Answer
C:Demonstrable success requires: Unique node identities produce the intended L1 or L2 adjacencies and routes cross only supported level boundaries. Applied case: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency.
Incorrect Answers
A:This option addresses a different service provider engineering topic (BGP path selection weight local preference and AS path) rather than the documented IS-IS NET area and Level-2 backbone design decision.
B:Redistribution changes protocol scope and metrics; uncontrolled mutual redistribution can create loops and excessive IGP state. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
D:Single topology shares reachability assumptions across enabled families, while multi-topology can maintain distinct IPv4 and IPv6 topology information. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
Question 118
The service provider operations team has not yet approved a change. Current evidence indicates: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency. Which evidence best tests the technical diagnosis before approving a disruptive change? Select ONE best answer.
- Inspect IPv6 link-local neighbors, interface instance and area data, OSPFv3 LSDB and installed IPv6 routes.
- Trace a known client flow through DNS resolution, IPv4 or IPv6 encapsulation, translator bindings and return path with packet captures.
- Examine NET values, level adjacency state, LSP originator IDs and intended area boundaries on a two-area diagram.
- Inspect member actor and partner state, bundle hashing, counters and traffic distribution under several representative flows.
Explanation
Correct Answer
C:IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability. Applied case: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency.
Incorrect Answers
A:Inspect IPv6 link-local neighbors, interface instance and area data, OSPFv3 LSDB and installed IPv6 routes. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
B:Trace a known client flow through DNS resolution, IPv4 or IPv6 encapsulation, translator bindings and return path with packet captures. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
D:Inspect member actor and partner state, bundle hashing, counters and traffic distribution under several representative flows. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
Question 119
A candidate correction has been tested and the platform team requires a post-change acceptance check. Original problem: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency. 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.
- Each intended adjacency reaches its required state and route advertisements are scoped correctly without unnecessary global routing changes.
- Unique node identities produce the intended L1 or L2 adjacencies and routes cross only supported level boundaries.
- Stable OSPFv3 adjacencies advertise the intended IPv6 prefixes with reachable next hops.
- Only planned prefixes cross the protocol boundary once and core convergence remains stable under service-route churn.
Explanation
Correct Answer
B:IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability. The result must be validated using the documented device, service or access context.
Incorrect Answers
A:Each intended adjacency reaches its required state and route advertisements are scoped correctly without unnecessary global routing changes. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
C:Stable OSPFv3 adjacencies advertise the intended IPv6 prefixes with reachable next hops. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
D:Only planned prefixes cross the protocol boundary once and core convergence remains stable under service-route churn. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
Question 120
For an original SPCOR service-provider engineering scenario, consider: Two service provider edge nodes are configured for Level-1-only operation but use different area identifiers and the operator expects intra-area adjacency. Select TWO complementary steps: the targeted correction and its strongest prechange validation.
- Change: Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops.
- Change: Assign unique IS-IS system IDs and consistent area identifiers for Level-1 adjacency, with proper Level-2 reachability across areas.
- Duplicate router system IDs to force adjacency and use mismatched Level-1 area addresses as a substitute for a backbone design.
- Check: Examine NET values, level adjacency state, LSP originator IDs and intended area boundaries on a two-area diagram.
- Check: Compare IS-IS IPv4 and IPv6 LSP TLVs, topology IDs, next-hop tables and controlled ping tests for each family.
Explanation
Correct Answer
B:IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability. Acceptance: Unique node identities produce the intended L1 or L2 adjacencies and routes cross only supported level boundaries.
D:IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability. Required intervention: Assign unique IS-IS system IDs and consistent area identifiers for Level-1 adjacency, with proper Level-2 reachability across areas.
Incorrect Answers
A:Change: Deploy route reflection with deliberate client and cluster design and preserve IGP reachability to advertised BGP next hops. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
C:For this select two assessment, the shortcut changes or bypasses the necessary routing, service or operational boundary rather than correcting it. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
E:Check: Compare IS-IS IPv4 and IPv6 LSP TLVs, topology IDs, next-hop tables and controlled ping tests for each family. IS-IS NET encodes an area and unique system identifier; Level-1 flooding is area scoped while Level-2 connects interarea backbone reachability.
