Automation & Programmability
Automation and programmability reflect the shift toward software-driven networking. This domain explains how controller-based and software-defined networks separate the control and data planes, how APIs let software configure devices, and how data formats like JSON structure information. It closes with configuration management tools that enforce consistent state.
Traditional vs. Controller-Based Networking
In traditional networking, each device runs its own control plane and is configured individually, which scales poorly. Controller-based networking centralizes control-plane intelligence in a controller that programs many devices from a single point. This reduces manual, error-prone configuration and speeds up changes. It also enables consistent policy across the whole network.
Software-Defined Networking and Planes
SDN separates the control plane, which decides how traffic is handled, from the data plane, which forwards it. A controller uses a southbound interface such as OpenFlow or NETCONF to instruct devices, and exposes a northbound API to applications. This abstraction lets applications request network behavior programmatically. The management plane handles monitoring and administration.
REST APIs and Data Formats
REST APIs let software configure and query devices over HTTP(S) using methods like GET, POST, PUT, and DELETE, typically secured with tokens or keys. Requests and responses commonly carry structured data in JSON, which represents information as key-value pairs, arrays, and nested objects. XML and YAML are alternative formats. Understanding JSON structure is key to parsing API results.
Configuration Management Tools
Tools like Ansible, Puppet, and Chef enforce a desired configuration state across many devices automatically and repeatably. Ansible is agentless, pushing YAML playbooks over SSH, while Puppet and Chef traditionally use agents and a pull model. These tools reduce configuration drift and human error. They make large-scale, consistent deployments practical and auditable.