8. Apply Concepts of Model Driven Programmability (YANG, RESTCONF, and NETCONF) in a Cisco Environment 200-901 Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A network engineer is using NETCONF to configure a Cisco device and receives an 'unknown-element' error for a specific tag in the XML payload. The engineer has verified that the YANG module is loaded on the device. What is the most likely cause?

   • AThe XML namespace is incorrect.
   • BThe user does not have permission to edit the element.
   • CThe device is running an older version of the YANG module.
   • DThe XML tag is not defined in the YANG module being used.
   Reveal Solution Discussion Select an answer first
2. 22application · medium

   A network administrator is writing a script to automate the initial configuration of a new Cisco IOS XE switch. The script must use NETCONF to push a full interface configuration and then verify that the configuration was applied. The administrator wants to ensure that if the configuration fails on one interface, the entire change is rolled back. Which NETCONF operation should the script use?

   • Alock and then unlock the configuration datastore around the edit-config operation.
   • Bget-config to retrieve the current configuration and then manually compare it after the change.
   • Cedit-config with the test-option set to 'test-then-set' and the error-option set to 'rollback-on-error'.
   • Dcopy-config to replace the running configuration with the new interface configuration.
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4. 23application · medium

   A network engineer is using NETCONF to change the description of an interface on a Cisco router. The engineer sends an edit-config with the new description, but the device returns an 'invalid-value' error. What is the most likely cause?

   • AThe interface does not exist on the device.
   • BThe engineer did not include the namespace in the XML payload.
   • CThe engineer used the wrong NETCONF operation, such as delete instead of merge.
   • DThe description string contains characters that are not allowed by the YANG model's type constraint.
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5. 24expert · hard

   A network engineer is using RESTCONF to configure a Cisco IOS XE device. The engineer sends a GET request to retrieve interface statistics, but receives a 404 Not Found error. The engineer has verified that the device has RESTCONF enabled and that the credentials are correct. What is the most likely cause of the 404 error?

   • AThe device does not support HTTPS.
   • BThe URI path is incorrect, such as using the wrong module name or data node.
   • CThe engineer is using the wrong HTTP method, such as POST instead of GET.
   • DThe device's YANG model is not loaded.
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6. 25application · medium

   A developer is building a monitoring application that must retrieve interface statistics from a Cisco device every 30 seconds. The application runs in a cloud environment and must use a lightweight, HTTP-based API that supports JSON. Which protocol and approach should the developer choose?

   • ARESTCONF over SSH using the POST method to /restconf/data/interfaces-state.
   • BNETCONF over HTTPS using the get-config operation to retrieve operational state.
   • CRESTCONF over HTTPS using the GET method to /restconf/data/interfaces-state.
   • DNETCONF over SSH using the get operation with a filter for interface statistics.
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