From time to time, you may have a requirement for looking into or even deploying a Load Balancing solution which will allow you to scale your platform to a larger implementation than what an individual server could give you.
You may have or be looking into deploying a farm of web servers, proxy servers or any other type of platform. All of which may be stand alone installations however you wish to achieve a single point of communication for your users.
If we take a web server environment for an example,
Lets say we would like to have www.example.com always present yet scalable and redundant for future growth. If we have this website running on a single web server, we have not only have a single point of failure, but we also have a limitation on capacity as we only have the local resources of that one server to scale with.