200-901 Practice Test 38 — 15 Questions

Question 1

A developer is creating an application that uses the Cisco Webex Teams API to send messages. What authentication method is typically used?

Accepted Answer

OAuth 2.0. The Cisco Webex Teams API uses OAuth 2.0 as its primary authentication method for applications that need to act on behalf of a user. OAuth 2.0 provides delegated access via access tokens, allowing the application to send messages without exposing user credentials. This is the standard for modern REST APIs that require secure, scoped access.

Answer

Session cookies

Answer

Basic Auth

Answer

API Key

Question 2

A network engineer is configuring a wireless network for a new office. To maximize performance and minimize interference, the engineer decides to use the 5 GHz band. Which of the following is a key advantage of 5 GHz over 2.4 GHz?

Accepted Answer

Less interference and more channels. 5 GHz offers more non-overlapping channels and less interference from common devices like microwaves and Bluetooth.

Answer

Better range through walls

Answer

Larger coverage area

Answer

Higher compatibility with older devices

Question 3

A Python script uses a dictionary to store device configuration parameters. Which key, if any, will raise a KeyError if it does not exist in the dictionary?

Accepted Answer

config['timeout']. Using square bracket notation (config['timeout']) on a dictionary will raise a KeyError if the specified key does not exist. This is a fundamental behavior of Python dictionaries: direct key access without a fallback mechanism throws an exception when the key is missing.

Answer

config.setdefault('timeout', 30)

Answer

config.get('timeout')

Answer

config.pop('timeout', None)

Question 4

A network engineer needs to automate the configuration of VLANs on a set of Cisco switches using Ansible. Which API should be targeted to ensure idempotent configuration updates?

Accepted Answer

NETCONF/YANG. NETCONF/YANG is the correct choice because NETCONF provides a transactional, lock-based mechanism that ensures idempotent configuration updates—applying the desired state exactly once without side effects from repeated runs. YANG models define the VLAN configuration structure, allowing Ansible to compare the current device state against the desired state and only push changes when necessary, which is the essence of idempotency.

Answer

REST API of Cisco DNA Center

Answer

SNMP

Answer

CLI with SSH

Question 5

An automation tool uses RESTCONF to configure a Cisco device. The device returns a 404 error for a PUT request. What does this indicate?

Accepted Answer

The resource does not exist. A 404 (Not Found) response to a RESTCONF PUT request indicates that the target resource (e.g., a specific YANG data node or URI) does not exist on the device. RESTCONF uses HTTP methods to manipulate resources identified by URIs; a PUT request is intended to create or replace a resource at that URI, but if the resource path is invalid or the data model node is not present, the server returns 404. This is consistent with RFC 8040, which defines the RESTCONF protocol.

Answer

The server is overloaded

Answer

The request body is malformed

Answer

Authentication failed

Question 6

A network team uses an Ansible playbook to automate the configuration of multiple Cisco IOS XE devices. The playbook includes the 'ios_config' module. Which of the following best describes the purpose of the 'provider' parameter in the ios_config module?

Accepted Answer

It defines the connection details for the device.. The 'provider' parameter in the ios_config module is a dictionary that encapsulates the connection details required to access the network device, such as hostname, username, password, port, and transport protocol (e.g., SSH). This allows the module to establish a session with the Cisco IOS XE device before applying configuration changes. Without the provider, the module would not know how to reach or authenticate to the target device.

Answer

It identifies the name of the playbook being used.

Answer

It specifies the configuration lines to be applied.

Answer

It sets the timeout for the module execution.

Question 7

An engineer needs to automate the deployment of a new VLAN across multiple switches. Which tool is best suited for this task?

Accepted Answer

Ansible. Ansible is the correct tool because it is an agentless automation platform that uses SSH to push configuration changes, such as VLAN deployment, to network devices. It allows engineers to define the desired state of VLANs in YAML playbooks and apply them consistently across multiple switches without manual intervention.

Answer

NetFlow

Answer

Syslog

Answer

SNMP

Question 8

A network administrator needs to assign IP addresses to 50 hosts in a subnet. Which subnet mask provides the minimum required number of usable addresses while minimizing waste?

Accepted Answer

255.255.255.192 (/26). A /26 subnet mask (255.255.255.192) provides 64 total addresses per subnet, of which 62 are usable (2^6 - 2 = 62). This is the smallest power-of-two block that can accommodate 50 hosts, minimizing waste while meeting the requirement.

Answer

255.255.255.224 (/27)

Answer

255.255.255.240 (/28)

Answer

255.255.255.128 (/25)

Question 9

In a CI/CD pipeline for network changes, which practice best ensures that a configuration push does not disrupt production traffic?

Accepted Answer

Canary deployment. Canary deployment is the correct practice because it gradually introduces the configuration change to a small subset of devices or traffic before full rollout. This allows monitoring for adverse effects and automatic rollback if issues arise, minimizing the risk of production disruption. In a CI/CD pipeline for network changes, this approach aligns with incremental validation and risk mitigation.

Answer

Disable rollback

Answer

Push all changes at once

Answer

Skip validation

Question 10

Which tool is specifically designed for model-driven programmability using YANG data models?

Accepted Answer

NETCONF. NETCONF is the correct answer because it is a network management protocol specifically designed to operate with YANG data models, using XML or JSON encoding to transport configuration and state data. YANG defines the structure of the data, and NETCONF provides the operations (get, edit-config, etc.) to manipulate that data in a model-driven, programmatic way. This makes NETCONF the standard tool for model-driven programmability in modern network automation.

Answer

SNMP

Answer

CLI

Answer

Ansible

Question 11

A network engineer is troubleshooting a Kubernetes deployment where pods are failing to start with the error 'CrashLoopBackOff'. The pod log shows 'bind: address already in use'. The deployment runs multiple replicas of a container that listens on port 8080. What is the most likely cause?

Accepted Answer

The deployment has hostPort: 8080 specified, causing port conflict when multiple replicas are scheduled on the same node.. The 'bind: address already in use' error indicates that the container's process cannot bind to port 8080 because it is already occupied. When `hostPort: 8080` is specified in the pod spec, Kubernetes instructs the container runtime to map the container port to the same port on the node's network namespace. If multiple replicas of the deployment are scheduled on the same node, each pod attempts to bind to port 8080 on the host, causing a conflict and the CrashLoopBackOff state. This is a common misconfiguration when using hostPort without ensuring that replicas are spread across different nodes.

Answer

The container is attempting to bind to a privileged port without the necessary capabilities.

Answer

The service is using NodePort and the node port is already in use.

Answer

Multiple containers in the same pod are trying to bind to the same port.

Question 12

A developer is troubleshooting a CI/CD pipeline that automatically deploys configuration changes to network devices. The pipeline includes a stage that runs Python unit tests. Which of the following would be a valid test to include in that stage to validate the configuration before deployment?

Accepted Answer

Test that the configuration file is valid JSON. Validating that the configuration is valid JSON is a simple unit test that can catch syntax errors early. The other options either require network access (which unit tests should avoid) or are not unit-level.

Answer

Test that the configuration can be applied to the device by sending it via NETCONF

Answer

Test that the configuration changes do not break connectivity by pinging the device after deployment

Answer

Test that the configuration adheres to company naming conventions using a regular expression

Question 13

A Python script uses the `requests` library to fetch device details from Cisco DNA Center. The API returns a JSON response with nested objects. To extract the management IP address from the response stored in variable `data`, which code snippet is correct? The JSON structure is:
{
  "response": [
    {
      "managementIpAddress": "192.168.1.1",
      "hostname": "router1"
    }
  ]
}

Accepted Answer

data['response'][0]['managementIpAddress']. The response contains a list under key 'response'; correct access is via data['response'][0]['managementIpAddress'].

Answer

data.managementIpAddress

Answer

data['response']['managementIpAddress']

Answer

data.get('response')[0].get('managementIpAddress')

Question 14

A network automation team uses a CI/CD pipeline. Which practice best ensures that configuration changes are validated before deployment to production?

Accepted Answer

Deploying to a staging environment that mirrors production. Deploying to a staging environment that mirrors production allows comprehensive testing without risk. This is a key DevOps best practice.

Answer

Automated unit tests that verify syntax of configuration files

Answer

Peer review of code only

Answer

Manual testing by the network engineer after deployment

Question 15

A developer needs to retrieve the current user's details from Webex API. Which endpoint should they call?

Accepted Answer

GET /v1/people/me. GET /v1/people/me returns details of the authenticated user.

Answer

GET /v1/rooms?me=true

Answer

POST /v1/people

Answer

GET /v1/people?email=current@user.com