200-901 Practice Test 2 — 10 Questions

Question 1

A network engineer is troubleshooting connectivity issues and wants to verify the path that packets take from a source to a destination IP address. Which OSI layer is primarily responsible for packet forwarding and routing?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Layer 3 - Network. The Network layer (Layer 3) is responsible for packet forwarding and routing, using logical IP addresses to determine the best path from source to destination. Protocols like IP (IPv4/IPv6) and routing protocols (e.g., OSPF, BGP) operate at this layer to make forwarding decisions. The traceroute command is a common tool that leverages Layer 3 TTL (Time-to-Live) fields to map the path packets take.

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Layer 4 - Transport

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Layer 1 - Physical

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Layer 2 - Data Link

Question 2

A DevOps engineer is managing a Git repository and wants to discard local changes to a file and revert it to the last committed state. Which TWO commands can accomplish this? (Choose two.)

Accepted Answer

git checkout -- . Both `git checkout -- ` and `git restore ` discard unstaged local changes to a file, reverting it to the content of the last commit (HEAD). `git checkout -- ` is the traditional command, while `git restore ` is the newer, more intuitive alternative introduced in Git 2.23. Both operate on the working tree without affecting the staging area or commit history.

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git reset --hard HEAD

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git stash drop

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git revert <file>

Question 3

A developer needs to send a message to a specific room in Webex using the API. What is the correct endpoint and required body parameter for the room destination?

Accepted Answer

POST /v1/messages with roomId parameter. To send a message to a Webex room, use POST /v1/messages with the roomId parameter to specify the target room.

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POST /v1/messages with toPersonEmail parameter

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POST /v1/memberships with roomId

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POST /v1/rooms with message text

Question 4

Match each HTTP status code to its meaning.

Accepted Answer

200 OK: Request succeeded.. The correct matches are: 200 OK = Request succeeded, 201 Created = Resource created successfully, 400 Bad Request = Malformed syntax or invalid request, 404 Not Found = Resource not found. Common confusions include swapping 200 and 201, as well as 400 and 404.

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200 OK: Resource created.

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404 Not Found: Bad request.

Question 5

In software architecture, which pattern separates an application into three interconnected components: Model (data), View (UI), and Controller (input logic)?

Accepted Answer

MVC (Model-View-Controller). The MVC pattern explicitly separates an application into three interconnected components: Model (data and business logic), View (user interface), and Controller (handles user input and updates the Model/View). This is the foundational architectural pattern for many web frameworks like Django, Ruby on Rails, and Spring MVC, where the Controller receives HTTP requests, interacts with the Model, and selects the appropriate View for rendering.

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Microservices

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Event-driven

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REST

Question 6

A Kubernetes cluster runs a microservice that needs to read configuration values from a ConfigMap and sensitive database credentials from a Secret. The pod manifest references both resources. How should the Secret be mounted to avoid exposing sensitive data in logs or environment variables?

Accepted Answer

Using a volume mount with a secret volume. Mounting a Secret as a volume stores the data in the tmpfs (RAM-backed filesystem) of the pod, which is not written to disk and is not exposed via environment variables that could be logged or printed by the application. This approach prevents accidental leakage of sensitive data through log outputs or environment variable dumps, as the application must explicitly read the file from the mount point.

Answer

Hardcoding the credentials in the ConfigMap

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Using a sidecar container to fetch secrets via API

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Using envFrom with secretRef

Question 7

In a network automation workflow, a developer needs to ensure idempotency. What does idempotency mean in this context?

Accepted Answer

Running the script once produces the same result as running it multiple times. Idempotency in network automation means that executing an operation multiple times results in the same network state as executing it once. For example, using a REST API PUT request to set a VLAN configuration will leave the device in the same state whether the request is sent once or repeatedly, because PUT is inherently idempotent. This prevents unintended side effects like duplicate VLANs or interface misconfigurations when a script is retried due to network failures or timeouts.

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The script uses a single API call

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The script can recover from failures

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The script can run on multiple devices simultaneously

Question 8

A developer needs to create a Python function that accepts any number of keyword arguments and prints them. Which function definition correctly uses **kwargs?

Accepted Answer

def print_args(**kwargs): print(kwargs). The **kwargs syntax in a Python function definition collects any number of keyword arguments into a dictionary. The function then prints that dictionary, which matches the requirement to accept and print any number of keyword arguments.

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def print_args(*args): print(args)

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def print_args(kwargs): print(kwargs)

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def print_args(*kwargs): print(kwargs)

Question 9

A network engineer configures an HTTP/2 server. Which feature of HTTP/2 reduces overhead by compressing headers using HPACK?

Accepted Answer

HPACK. HPACK is the header compression mechanism specified for HTTP/2 (RFC 7541). It reduces overhead by encoding HTTP headers into a compact binary format using static and dynamic tables, eliminating redundant header data across requests. This directly addresses the question's focus on reducing overhead through header compression.

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Server push

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Binary framing layer

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Multiplexed streams

Question 10

An application developer is using a protocol that does not require a connection setup and has minimal header overhead. Which transport protocol is being used?

Accepted Answer

UDP. UDP (User Datagram Protocol) is a connectionless transport-layer protocol that does not require a handshake (no SYN/SYN-ACK/ACK) and has minimal header overhead (only 8 bytes, compared to TCP's 20 bytes). This makes it ideal for applications like DNS queries, streaming media, or real-time communications where low latency is more critical than guaranteed delivery.

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TCP

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HTTP

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ICMP