External layers
On top of the web server, there is the possibility to continue the link by adding extra levels that work on the HTTP layer. This allows you to load balance between multiple servers and increase the total throughput of the system. This can be chained into multiple layers, if necessary.
Figure 6.6: Chained load balancers
The route from the user to the edge of our system is handled by the internet, but once it reaches the edge load balancer, it directs the requests inside the system. The edge load balancer works as a gateway between the external networks and the controlled environment of our network.
The edge load balancer is normally the only one that handles HTTPS connection, allowing the rest of the system to use only HTTP. This is convenient as HTTP requests are easier to cache and handle. HTTPS requests are encoded end to end and cannot be properly cached or analyzed. The internal traffic is protected from external access and should have robust...
