An engineer must run tests on several Cisco controllers. Due to the nature of the task, the infrastructure must be running at all times and have access to APIs. Which Cisco DevNet source must the engineer use?

The Cisco DevNet Sandbox is a service that provides developers with free, 24/7 access to live Cisco hardware and software environments for development and testing purposes. The "Always-On" sandboxes are shared, pre-configured labs that are continuously available, directly fulfilling the requirement for an infrastructure that is "running at all times." These sandboxes expose the necessary APIs for an engineer to run tests against various Cisco controllers (e.g., Cisco DNA Center, SD-WAN) without needing to deploy and maintain physical or virtual infrastructure.

A. DevNet Learning Labs: These are structured, guided tutorials designed for learning specific tasks, not for open-ended, custom testing on an always-on platform.
B. DevNet Code Exchange: This is a repository of sample code, SDKs, and projects. It provides code to run but is not the execution environment itself.
D. DevNet API documentation: This provides the reference material and specifications for using APIs. It is a resource for information, not a live testing environment.

1. Cisco DevNet Sandbox Documentation: "The Cisco DevNet Sandbox provides a free, 24/7, always-on environment for you to learn, build, and test with Cisco technologies... Always-On labs are available 24/7 for you to use without a reservation."

Source: Cisco DevNet, "Sandbox." Retrieved from https://developer.cisco.com/sandbox/

2. Cisco DEVASC 200-901 Official Cert Guide: "The DevNet Sandbox provides developers with a way to get hands-on experience with Cisco products and platforms... The Always-On labs are shared environments that are available 24/7 without the need for a reservation."

Source: Gooley, J., Jackson, C., et al. (2020). Cisco DEVASC 200-901 Official Cert Guide. Cisco Press. Chapter 2, "Examining the Cisco DevNet Website and Resources," Section: "DevNet Sandbox."

3. Cisco DevNet Learning Labs Overview: "Learning Labs are short, step-by-step tutorials that help you get hands-on with a Cisco technology."

Source: Cisco DevNet, "Learning Labs." Retrieved from https://developer.cisco.com/learning/