9. Construct code to perform a specific operation based on a set of requirements and given API reference documentation

📘Cisco DevNet Associate (200-901 DEVASC)

This topic focuses on using REST APIs to retrieve information about devices (clients/hosts) connected to a network.

For the exam, you must understand:

What a client/host means
How Meraki and Cisco DNA Center track clients
How to authenticate to APIs
How to construct API requests
How to handle responses (JSON)
How to write basic Python code to retrieve client data
How filtering and query parameters work

We will explain everything in simple and clear language.

1. What Is a Client or Host?

A client or host is any device connected to a network.

Examples in an IT environment:

Laptop connected to office Wi-Fi
Desktop connected via Ethernet
IP phone
Network printer
Mobile phone connected to wireless
Server connected to switch

When connected, these devices generate network traffic. Network platforms like:

Cisco Meraki
Cisco DNA Center

can detect and store information about these devices.

2. Why Do We Need to Obtain a List of Clients?

In real IT environments, administrators need to:

Monitor connected devices
Identify unauthorized devices
Troubleshoot connectivity issues
Track bandwidth usage
Perform security checks
Generate audit reports

Instead of manually checking dashboards, developers use APIs to automatically retrieve this information.

This is what the DEVASC exam tests — your ability to write code that interacts with APIs.

3. Using Cisco Meraki to Obtain Client List

3.1 What Is Cisco Meraki?

Cisco Meraki provides cloud-managed networking devices such as:

Switches
Wireless access points
Security appliances

All data is accessible through the Meraki Dashboard API.

3.2 Authentication in Meraki

Meraki uses:

API Key authentication

Steps:

Generate API key from Meraki Dashboard.
Send API key in HTTP header:

X-Cisco-Meraki-API-Key: YOUR_API_KEY

3.3 Important API Endpoint for Clients

To obtain clients in a network:

GET /networks/{networkId}/clients

Full URL:

https://api.meraki.com/api/v1/networks/{networkId}/clients

3.4 Required HTTP Components

Method

GET

Headers

X-Cisco-Meraki-API-Key
Content-Type: application/json

3.5 Example Python Code (Meraki)

import requestsAPI_KEY = "YOUR_API_KEY"
NETWORK_ID = "YOUR_NETWORK_ID"url = f"https://api.meraki.com/api/v1/networks/{NETWORK_ID}/clients"headers = {
    "X-Cisco-Meraki-API-Key": API_KEY,
    "Content-Type": "application/json"
}response = requests.get(url, headers=headers)if response.status_code == 200:
    clients = response.json()
    for client in clients:
        print("Client Name:", client.get("description"))
        print("IP Address:", client.get("ip"))
        print("MAC Address:", client.get("mac"))
        print("VLAN:", client.get("vlan"))
        print("----------------------")
else:
    print("Error:", response.status_code)

3.6 Important Fields Returned

Meraki returns JSON data such as:

description (client name)
mac
ip
vlan
usage
manufacturer
status
switchport

You must understand how to:

Parse JSON
Loop through results
Extract specific fields

3.7 Query Parameters

Meraki allows filtering using parameters:

Example:

?perPage=100
?timespan=86400

These help:

Limit number of results
Filter by time range

Understanding query parameters is important for the exam.

4. Using Cisco DNA Center to Obtain Client List

4.1 What Is Cisco DNA Center?

Cisco DNA Center is an enterprise network controller used to manage:

Campus networks
Wireless networks
Network automation
Assurance and monitoring

It provides a REST API for client information.

4.2 Authentication in Cisco DNA Center

DNA Center uses:

Token-based authentication

Step 1: Get token

POST /dna/system/api/v1/auth/token

You must send:

Basic authentication (username/password)

Response:

{
  "Token": "your_token_here"
}

Step 2: Use token in header:

X-Auth-Token: your_token_here

4.3 API Endpoint to Get Clients

Example endpoint:

GET /dna/intent/api/v1/client-health

GET /dna/intent/api/v1/client-detail

Full URL example:

https://dnacenter.example.com/dna/intent/api/v1/client-health

4.4 Example Python Code (DNA Center)

import requests
from requests.auth import HTTPBasicAuthBASE_URL = "https://dnacenter.example.com"
USERNAME = "admin"
PASSWORD = "password"# Step 1: Get Token
auth_url = f"{BASE_URL}/dna/system/api/v1/auth/token"
auth_response = requests.post(auth_url, auth=HTTPBasicAuth(USERNAME, PASSWORD), verify=False)token = auth_response.json()["Token"]# Step 2: Get Clients
headers = {
    "X-Auth-Token": token,
    "Content-Type": "application/json"
}client_url = f"{BASE_URL}/dna/intent/api/v1/client-health"
response = requests.get(client_url, headers=headers, verify=False)if response.status_code == 200:
    clients = response.json()
    print(clients)
else:
    print("Error:", response.status_code)

5. Key Differences Between Meraki and DNA Center

Feature	Meraki	DNA Center
Authentication	API Key	Token
Hosted	Cloud	On-premises
API Style	REST	REST
Header	X-Cisco-Meraki-API-Key	X-Auth-Token

You must understand these differences for exam questions.

6. Important REST API Concepts for Exam

6.1 HTTP Methods

GET → Retrieve data
POST → Create data
PUT → Update data
DELETE → Remove data

For this topic, mainly GET is used.

6.2 Status Codes

200 → Success
201 → Created
400 → Bad request
401 → Unauthorized
403 → Forbidden
404 → Not found
500 → Server error

You must know how to check response.status_code.

6.3 JSON Handling

API responses are in JSON format.

You must understand:

response.json()

And extracting values:

client["ip"]
client.get("mac")

7. Common Exam Scenarios

The exam may ask you to:

Complete missing Python code
Identify correct API endpoint
Choose correct authentication method
Identify correct header
Interpret JSON output
Identify correct HTTP method
Understand filtering parameters

8. Security Best Practices

For the exam, remember:

Do not hardcode API keys in production
Store credentials securely
Use HTTPS
Handle token expiration
Handle errors properly

9. Typical Workflow Summary

When obtaining client list:

Identify platform (Meraki or DNA Center)
Authenticate (API key or token)
Build correct endpoint URL
Send GET request
Check status code
Parse JSON response
Extract required client information

10. Final Exam Preparation Checklist

You should be able to:

✅ Explain what a client/host is
✅ Identify Meraki client endpoint
✅ Identify DNA Center client endpoint
✅ Explain API key authentication
✅ Explain token authentication
✅ Write Python code using requests
✅ Parse JSON response
✅ Understand HTTP status codes
✅ Use query parameters
✅ Compare Meraki and DNA Center

Final Conclusion

In this DEVASC exam section, you are expected to:

Use REST APIs
Write Python code
Authenticate properly
Retrieve client/host information
Handle JSON responses correctly

The main goal is to automate the retrieval of connected device information from:

Cisco Meraki
Cisco DNA Center

If you understand authentication, endpoints, headers, JSON parsing, and Python requests library, you will confidently pass this section of the exam.