Infrastructure as Code (IaC) means managing infrastructure through code files rather than manual processes. Your network configuration lives in repositories, not just on devices.
Declarative definitions. Describe what you want, not how to get there. The tool figures out the steps.
Version control. All configuration lives in Git. Every change is tracked and reversible.
Reproducibility. Given the same code, you get the same infrastructure every time.
Benefits: Disaster recovery improves. Auditing simplifies. Testing enables you to apply code in lab before production.