14. Interpret Sequence Diagram That Includes API Calls 200-901 Practice Questions (Page 2)

Questions 6–10

1. 6expert · hard

   A sequence diagram for a multi-service architecture shows three lifelines: 'Client', 'API Gateway', and 'Backend Service'. The diagram shows a synchronous request from the Client to the API Gateway, then a synchronous request from the API Gateway to the Backend Service, and then a response from the Backend Service to the API Gateway, followed by a response from the API Gateway to the Client. The engineer needs to determine the total number of activation bars on the API Gateway lifeline. Which statement is correct?

   • AThere are three activation bars: one for the Client request, one for the Backend request, and one for the Backend response.
   • BThere is one activation bar that spans from the receipt of the Client's request to the sending of the response to the Client.
   • CThere are two activation bars: one for receiving the Client's request and one for sending the response to the Client.
   • DThere are no activation bars because the API Gateway is a passive component.
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2. 7application · easy

   A sequence diagram shows three lifelines: Automation Script, REST API, and Database. The messages are: 1) Script sends GET /inventory to API, 2) API sends SQL SELECT to Database, 3) Database returns rows to API, 4) API returns JSON to Script. Which statement correctly describes the temporal order?

   • AThe SQL query is sent before the GET /inventory request is received by the API.
   • BThe API returns JSON to the Script before the Database returns rows.
   • CThe Script receives the JSON response before the API sends the SQL query.
   • DThe Database returns rows to the API before the API returns JSON to the Script.
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4. 8application · medium

   A sequence diagram shows an API client sending a PUT /config request. The response is a 401 Unauthorized. The diagram then shows a self-message 'refresh token' on the client, followed by a second PUT /config request. What does this sequence represent?

   • AThe client sends a different request to update the token.
   • BThe server refreshes the client's token automatically.
   • CThe client refreshes its authentication token and retries the request.
   • DThe client aborts the operation and does not retry.
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5. 9application · medium

   A network automation engineer is reviewing a UML sequence diagram that models the interaction between a Python script, the Cisco DNA Center API, and a network device. The diagram shows the script sending a request to the DNA Center API, then a solid arrow from DNA Center to the device, and finally a dashed arrow from the device back to DNA Center, followed by a dashed arrow from DNA Center to the script. The engineer needs to determine whether the script's request is synchronous or asynchronous. Which observation from the diagram confirms the synchronous nature?

   • AThe script's activation bar remains active until the dashed return arrow from DNA Center arrives.
   • BThe message from the script to DNA Center is labeled with a request/response stereotype.
   • CThe device sends a dashed arrow back to DNA Center before DNA Center responds to the script.
   • DThe script's lifeline ends immediately after sending the message to DNA Center.
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6. 10application · easy

   In a sequence diagram, an automation controller sends a message to a network device with a solid arrowhead and a dashed return arrow. What does this notation indicate?

   • AA notification event that does not require a response.
   • BAn asynchronous request where the controller does not wait for a response.
   • CA self-message indicating an internal method call.
   • DA synchronous request where the controller waits for the response before continuing.
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