The Azure Application Gateway offers an Application Delivery Controller (ADC), which operates on the application layer (layer seven in the OSI network reference stack).
It provides web load balancing, so it provides load balancing on layer seven, which is for HTTP(S) only. It also provides a web application firewall, which can be leveraged to protect your apps from common web-based attacks, such as cross-site scripting, SQL injection, and session-hijacking (this is described in more detail in the Network Security Strategies section in this chapter). It can decrypt HTTPS traffic, so you can install your SSL certificates on the application gateway instead of onto the different web servers. This way, the web servers don't have to take care of this and management will be easier because it is all in one place. Application Gateway will then encrypt the...