Even mobile applications are often web applications in the sense
that the mobile application you are interacting with is communi‐
cating with a web server remotely using web-based protocols and
technologies.
When we talk about web-based technologies, we are talking about protocols and lan‐
guages like HTTP, HTML, XML, and SQL. This also suggests that we are communi‐
cating with a web server, meaning a server that communicates using HTTP, which
may be secured using TLS for encryption. Much of this is what happens between the
server and the client, but doesn’t necessarily describe what may be happening with
other systems within the network design. To help you fully understand, we’ll talk
about the systems you may run into within a web application architecture. We will
start at the customer-facing end and then work our way inward to the most sensitive
components.
Figure 8-1
will be a reference point for us going forward. To simplify it a
little, some of the connection lines are missing. In reality, the load balancers would
cross-connect with all of the web servers, for example. However, at some point all of
the cross-connections start to clutter the image.
Figure 8-1. Sample web architecture