Most applications expose some sort of API that governs how an application can be accessed by other applications. APIs provide a set of routines, protocols, tools and documentation which can be leveraged for programmatic interaction. They represent a means through which elements or applications can be programmatically controlled and describe how external applications can gain access to capabilities and functions within another application. APIs have four primary components:

• Methods: Describes the mechanism of the API implementation including how resources communicate and provide encapsulation.
• Actions: This is the intent of the API call, often referred to as a "verb". It describes the operations available such as GET, PUT, POST, and DELETE
• Objects: This is the resource the user is trying to access. This is often referred to as a noun and it is typically a URI.
• Formats: This is how the data is represented, such as, JSON and XML.

API Framework

The following characteristics of an API enable users to build a more efficient, manageable and reliable network via automation.

• Modularity: Applications can be built leveraging clearly defined and reusable modules
• Abstraction: APIs abstract the details of the underlying implementation from the higher level logic that invokes it
• Stability: APIs provide a stable and consistent interface

Cisco Open NX-OS exposes three primary APIs:

• NX-API REST - HTTP-based RESTful API
• NX-API CLI - RPC-based API
• NETCONF API

Each of these APIs can be used with multiple language bindings. There are Python bindings for both NX-API REST and NX-API CLI.

This chapter will explore the Open NX-OS RESTful APIs in more detail.