Cisco Certified DevNet Associate (200-901) Exam Guide

The DevNet Associate Exam v1.1 (DEVASC 200-901) is a 120-minute evaluation affiliated with the DevNet Associate – Developer Certification. This exam validates a candidate’s expertise in software development and design, specifically focusing on API utilization, application deployment and security, along with infrastructure and automation on Cisco platforms. The course titled “Developing Applications and Automating Workflows using Cisco Core Platforms” is designed to equip candidates with the necessary skills and knowledge for this exam.

1.0 Software Development and Design

This domain equips candidates with a robust foundation in the principles and practices of modern software development, particularly as they apply to networked applications on Cisco platforms. It covers everything from understanding different data formats like XML, JSON, and YAML—which are essential for configuration and data interchange—to the intricacies of parsing these formats into usable structures in Python. This is crucial for manipulating data received from APIs or other data sources.

Test-driven development (TDD) is emphasized, teaching candidates how to improve software quality and reliability by writing tests before the actual functional code. This aligns with various software development methodologies such as Agile, Lean, and Waterfall, each offering distinct advantages depending on the project scope and requirements. The domain also delves into the best practices for code organization—using methods, functions, classes, and modules—to enhance maintainability and scalability.

Moreover, understanding common design patterns like MVC (Model-View-Controller) and Observer is vital for creating well-structured, efficient applications. Version control using Git is another critical area, enabling effective collaboration and change management in software projects.

• Compare data formats (XML, JSON, and YAML): Understanding these data formats is crucial because they are widely used in configurations, data exchange, and APIs. Each has its strengths and is chosen based on use case requirements.
• Describe parsing of common data format (XML, JSON, and YAML) to Python data structures: This is important as it enables developers to manipulate, analyze, and utilize data effectively within applications.
• Describe the concepts of test-driven development: This methodology improves code quality and reliability by encouraging developers to write tests before code, ensuring each function is tested as it’s developed.
• Compare software development methods (agile, lean, and waterfall): Knowledge of these methodologies helps in selecting the appropriate approach for project management and development pace, influencing project success.
• Explain the benefits of organizing code into methods/functions, classes, and modules: Organized code enhances readability, maintainability, and reusability, crucial factors in long-term project sustainability.
• Identify the advantages of common design patterns (MVC and Observer): Design patterns provide proven solutions to common problems, facilitating efficient problem-solving and robust software architecture.
• Explain the advantages of version control: Using version control systems like Git helps in tracking changes, collaborating on projects, and maintaining a history of work, which is vital for team environments and complex projects.
• Utilize common version control operations with Git: Mastery of Git operations such as clone, commit, push, pull, and merge supports effective source code management, essential for continuous integration and deployment processes.

2.0 Understanding and Using APIs

APIs (Application Programming Interfaces) are fundamental to modern software architecture, allowing discrete systems to communicate and function cohesively. This domain focuses on constructing and utilizing REST APIs, understanding the full lifecycle from request construction based on documentation, to handling responses and understanding HTTP status codes. Troubleshooting skills are sharpened through interpreting API errors and managing common issues like rate limiting.

Moreover, the use of webhooks as a means to receive real-time data updates, and the implementation of various authentication mechanisms—such as basic auth, custom tokens, and API keys—are covered to ensure secure and effective API integration. Comparative analysis of API styles, including REST and RPC, synchronous and asynchronous calls, equips candidates with the ability to choose the appropriate API architecture for their development needs.

• Construct a REST API request to accomplish a task given API documentation: Demonstrates the ability to integrate and interact with external software components, a critical skill in today’s interconnected digital ecosystems.
• Describe common usage patterns related to webhooks: Understanding webhooks provides insights into asynchronous event handling, crucial for creating reactive, efficient applications.
• Identify the constraints when consuming APIs: Recognizing limitations such as rate limiting and data caps ensures reliable and respectful API use that adheres to external service constraints.
• Explain common HTTP response codes associated with REST APIs: Knowledge of response codes like 200, 400, and 500 series is essential for troubleshooting and ensuring smooth communication between services.
• Troubleshoot a problem given the HTTP response code, request, and API documentation: Ability to diagnose and resolve issues based on API feedback is vital for maintaining application reliability and user satisfaction.
• Identify the parts of an HTTP response (response code, headers, body): Understanding these components helps in parsing and leveraging responses effectively in application logic.
• Utilize common API authentication mechanisms: basic, custom token, and API keys: Securely managing authentication is crucial for protecting access to services and data, especially in distributed environments.
• Compare common API styles (REST, RPC, synchronous, and asynchronous): This comparison aids in choosing the appropriate architecture style for optimal performance and compatibility in application development.

3.0 Cisco Platforms and Development

Leveraging Cisco’s extensive platform capabilities, this domain explores how to develop applications that integrate and interact with Cisco’s software-defined networking, management, and security products. It involves hands-on activities such as creating scripts using Cisco SDKs and APIs across various Cisco platforms—such as Meraki, DNA Center, ACI, SD-WAN, and NSO.

Candidates learn to describe and utilize the capabilities of different Cisco management and operation tools, integrating systems like UCS Manager and Cisco Intersight for compute management, and deploying collaboration tools such as Webex. The understanding of device-level APIs for IOS XE and NX-OS allows for deeper device management and customization.

• Construct a Python script that uses a Cisco SDK given SDK documentation: This highlights the practical application of Cisco-specific tools and SDKs to harness the full potential of Cisco platforms in solutions.
• Describe the capabilities of Cisco network management platforms and APIs (Meraki, Cisco DNA Center, ACI, Cisco SD-WAN, and NSO): An understanding of these platforms enables tailored solutions that leverage Cisco’s powerful networking capabilities.
• Describe the capabilities of Cisco compute management platforms and APIs (UCS Manager and Intersight): Familiarity with these platforms ensures efficient management of compute resources, crucial for maintaining robust IT infrastructure.
• Describe the capabilities of Cisco collaboration platforms and APIs (Webex, Webex devices, Cisco Unified Communication Manager including AXL and UDS interfaces): This enables the integration and enhancement of collaboration solutions, a key area in improving business communication and productivity.
• Describe the capabilities of Cisco security platforms and APIs (XDR, Firepower, Umbrella, Secure Endpoint, ISE, and Secure Malware Analytics): Knowledge of these platforms empowers developers to build advanced security into their applications, crucial in today’s high-threat digital environment.
• Describe the device level APIs and dynamic interfaces for IOS XE and NX-OS: Understanding these APIs allows for direct interaction and control over Cisco devices, enabling deep customization and automation.
• Identify the appropriate DevNet resource for a given scenario (Sandbox, Code Exchange, support, forums, Learning Labs, and API documentation): Leveraging these resources effectively accelerates learning and solution development within the Cisco ecosystem.
• Apply concepts of model driven programmability (YANG, RESTCONF, and NETCONF) in a Cisco environment: This demonstrates an advanced level of network configuration and automation, essential for modern network management.

4.0 Application Deployment and Security

This domain prepares candidates to deploy and secure applications effectively, teaching the benefits of edge computing and the differences between deployment models including cloud (public, private, hybrid) and on-premises solutions. It stresses the importance of containerization technologies like Docker, and orchestration with Kubernetes, explaining their role in creating scalable and manageable application environments.

Security is a major focus, with comprehensive coverage of securing applications at every level—from protecting secrets and managing encryption for data at rest and in transit, to implementing security best practices in line with the OWASP Top Ten web application security risks.

• Describe benefits of edge computing: Edge computing reduces latency and bandwidth use by processing data locally, enhancing application performance, especially in IoT and real-time processing scenarios.
• Identify attributes of different application deployment models (private cloud, public cloud, hybrid cloud, and edge): Understanding these models helps in selecting the optimal deployment strategy based on security, scalability, and compliance requirements.
• Identify the attributes of these application deployment types (Virtual machines, Bare metal, Containers): Each deployment type offers unique benefits and is suited for different application needs and environments.
• Describe components for a CI/CD pipeline in application deployments: A CI/CD pipeline automates steps in software delivery, ensuring faster, more reliable releases.
• Construct a Python unit test: Unit testing verifies the functionality of parts of applications independently, essential for early bug detection and streamlined development.
• Interpret contents of a Dockerfile: Understanding a Dockerfile aids in building reproducible, consistent environments, crucial for development and production parity.
• Utilize Docker images in local developer environment: Docker streamlines development by allowing developers to create isolated environments that mimic production systems.
• Identify application security issues related to secret protection, encryption (storage and transport), and data handling: Securing applications requires a thorough understanding of potential vulnerabilities and implementing robust security measures at all levels.
• Explain how firewall, DNS, load balancers, and reverse proxy in application deployment: These components are pivotal in scaling, securing, and managing traffic within IT infrastructures, ensuring efficient and secure data flow.
• Describe top OWASP threats (such as XSS, SQL injections, and CSRF): Knowledge of common web vulnerabilities enables developers to implement security measures to protect against widespread threats.
• Utilize Bash commands (file management, directory navigation, and environmental variables): Command-line proficiency is crucial for navigating and managing systems effectively, especially in Linux-based environments.
• Identify the principles of DevOps practices: DevOps integrates development and operations teams to improve collaboration and increase the efficiency of development processes.

5.0 Infrastructure and Automation

Focusing on the automation of network and infrastructure tasks, this domain covers the transformative impact of model-driven programmability using technologies like YANG, NETCONF, and RESTCONF. It explores the integration of infrastructure as code principles, utilizing tools such as Ansible and Terraform to automate the provisioning and management of networking resources.

The domain also dives into the use of Cisco’s automation platforms and tools to create efficient, repeatable, and scalable operations processes. Understanding Cisco Modeling Labs and pyATS enhances candidates’ abilities to simulate network environments and automate testing processes, crucial for ensuring the reliability and robustness of network configurations.

• Describe the value of model driven programmability for infrastructure automation: This approach uses models to automate the provisioning and management of network infrastructure, greatly improving efficiency and accuracy.
• Compare controller-level to device-level management: Understanding the differences between these management levels helps in choosing the right approach for scaling and managing network environments.
• Describe the use and roles of network simulation and test tools (such as Cisco Modeling Labs and pyATS): Simulation tools allow for testing and verification of network changes in a risk-free environment, essential for planning and training.
• Describe the components and benefits of CI/CD pipeline in infrastructure automation: Integrating CI/CD practices in network management ensures continuous integration and deployment of network changes, minimizing downtime and errors.
• Describe principles of infrastructure as code: This practice treats infrastructure setup and changes as code, facilitating automation, version control, and consistent environments across development, testing, and production.
• Describe the capabilities of automation tools such as Ansible, Terraform, and Cisco NSO: These tools automate the configuration and management of networks, improving speed and reducing manual errors in network changes.
• Identify the workflow being automated by a Python script that uses Cisco APIs including ACI, Meraki, Cisco DNA Center, and RESTCONF: Understanding how to script interactions with Cisco APIs allows for customized automation and integration of Cisco products into broader IT systems.
• Identify the workflow being automated by an Ansible playbook (management packages, user management related to services, basic service configuration, and start/stop): Playbooks outline the steps Ansible will execute to change systems and software in predefined ways, standardizing and simplifying administrative tasks.
• Identify the workflow being automated by a bash script (such as file management, app install, user management, directory navigation): Bash scripts automate routine command-line tasks, enhancing efficiency and reliability of administrative operations.
• Interpret the results of a RESTCONF or NETCONF query: These protocols allow for management and configuration of network devices, and interpreting their outputs is essential for network monitoring and management.
• Interpret basic YANG models: YANG provides a structured format for modeling network elements and operations, pivotal in model-driven network management.
• Interpret a unified diff: Understanding the output of a diff helps in recognizing changes between file versions, essential for code reviews and audits.
• Describe the principles and benefits of a code review process: Code reviews improve code quality by facilitating collaboration among developers to find and fix errors before production.

6.0 Network Fundamentals

• Describe the purpose and usage of MAC addresses and VLANs: MAC addresses identify network devices, while VLANs help in logically segmenting networks without requiring physical separation.
• Describe the purpose and usage of IP addresses, routes, subnet mask / prefix, and gateways: These components are fundamental to IP networking, directing traffic across local networks and the internet.
• Describe the function of common networking components (such as switches, routers, firewalls, and load balancers): These devices play critical roles in data transmission, security, and traffic management across networks.
• Interpret a basic network topology diagram with elements such as switches, routers, firewalls, load balancers, and port values: Ability to read and understand network diagrams is essential for planning, troubleshooting, and managing network setups.
• Describe the function of management, data, and control planes in a network device: These planes separate different types of traffic, ensuring that management or operational data does not interfere with user data.
• Describe the functionality of these IP Services: DHCP, DNS, NAT, SNMP, NTP: These services support the operation of networks by assigning addresses, translating names to addresses, managing device settings, and synchronizing time across devices.
• Recognize common protocol port values (such as, SSH, Telnet, HTTP, HTTPS, and NETCONF): Knowing what services typically use which ports can help configure firewalls and troubleshoot network services.
• Identify cause of application connectivity issues (NAT problem, Transport Port blocked, proxy, and VPN): Effective troubleshooting of connectivity issues requires understanding how various network functions can interfere with application access.
• Explain the impacts of network constraints on applications: Network limitations such as bandwidth, latency, and packet loss can significantly affect application performance and reliability.