Understanding a concept and learning how to do a specific task is very fulfilling for most people who are seeking to learn something. However, this section will take you beyond that and will introduce what is going on behind the scenes, what Microsoft uses to get its Azure networking to work properly, and so on.

Microsoft Azure mainly takes advantage of Software-Defined Networking (SDN) for the internal operations of Azure, but this is not the case for the case when the customers work with Azure as they are communicating with Azure via the internet most of the time, which is called the edge. In this part of the network, Microsoft uses physical networking.

Put simply, the concept of using virtual networks with subnets and virtual network gateways is running on the backbone of Azure. However, on the edge physical network devices, such as routers, switches, firewalls, and so on, are used.

Throughout the book, all of the SDN services, such as Azure Load Balancers, Traffic Manager, Application Gateway, and so on, will be covered.