300-920 Question #37: Real Exam Question with Answer & Explanation

The correct answer is B. HttpClient can be used to send requests but not receive responses. D. The HttpClient command can be used to send requests and read responses over HTTP.. In Cisco CE 9.8's xAPI framework, B and D are correct because they describe two distinct roles of HTTP-based communication. Option D is correct: xCommand HttpClient - introduced as a key CE 9.8 feature - allows the Cisco device itself to initiate outbound HTTP/HTTPS requests to e

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Question

With CE 9.8 and above, which two statements are correct when an application is sending and receiving data over a connection established with an xAPI interface? (Choose two.)

Options

AAll Serial, SSH, and WebSockets can be used to send and receive data.
BHttpClient can be used to send requests but not receive responses.
CHttpFeedback is the only option to receive data.
DThe HttpClient command can be used to send requests and read responses over HTTP.
EWebSockets is the only option to send and receive data.

Explanation

In Cisco CE 9.8's xAPI framework, B and D are correct because they describe two distinct roles of HTTP-based communication. Option D is correct: xCommand HttpClient - introduced as a key CE 9.8 feature - allows the Cisco device itself to initiate outbound HTTP/HTTPS requests to external services and read the response bodies back. Option B is correct from the application's perspective: when an external application connects to the device as an HTTP client to issue xAPI commands, it can only send requests; it cannot receive unsolicited or push-based event data through that same HTTP channel - for that, it needs WebSockets or HttpFeedback registrations.

Why the distractors are wrong:

A is wrong because it falsely equates Serial, SSH, and WebSockets as uniformly interchangeable for this purpose - they have different capabilities and CE 9.8 xAPI doesn't treat them identically.
C is wrong because HttpFeedback is not the only way to receive data; WebSockets provides full-duplex, bidirectional communication and is a valid alternative.
E is wrong because WebSockets is not the only bidirectional option - SSH and Serial connections also support two-way data flow over xAPI.

Memory tip: Think of it as two separate hats - when the device wears the hat (xCommand HttpClient), it can both send and read responses (D). When an app wears the hat connecting via HTTP, it can only send; receiving requires a different mechanism like WebSockets (B).

Topics

#xAPI interface#CE endpoints#HTTP methods#WebSockets

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