Chapter 2
Low-Level Network Device Interactions
Section 2
The Challenges of the CLI
While it is hard to imagine any networking device coming out today without an Application Program Interface (API) for programmatic communication, it is a known fact that many of the network devices deployed in previous years did not contain API interfaces. The intended method of management for those devices was through Command Line Interfaces (CLIs) using terminal programs, which were originally developed with a human engineer in mind. The management relied on the engineer's interpretation of the data returned from the device for appropriate action. As the number of network devices and the complexity of the network grew, it became increasingly difficult to manually manage them one by one. Let’s look at it in detail.