In my opinion, IP routing is about having the intermediate devices between the two endpoint transmit the packets between them based the IP header. For every communication on the internet, the packet will traverse through various intermediate devices. As mentioned, the intermediate devices consist of routers, switches, optical gears, and various other gears that do not examine beyond the network and transport layer. In a road trip analogy, you might travel in the United States from the city of San Diego in California to the city of Seattle in Washington. The IP source address is analogous to San Diego and the destination IP address can be thought of as Seattle. On your road trip, you will stop by many different intermediate spots, such as Los Angeles, San Francisco, and Portland; these can be thought of as the routers and switches between the source and destination.

Why was this important? In a way, this book is about managing and optimizing these intermediate devices. In the age of mega datacenters that span sizes of multiple American football fields, the need for efficient, agile, cost effective way to manage the network becomes a major point of competitive advantage for companies. In the future chapters, we will dive into how we can use Python programming to effectively manage the network.