N-Tier Solutions
This is essentially client/server where the application is distributed over three or more separate layers. These in turn can be distributed over three or more separate computers in a distributed network.
The advantage this affords is better resilience, scalability and also a looser coupling between each of the application layers. It also means that layers can be designed and worked on independently and layers replaced (i.e. perhaps from heavy client to web for the presentation tier).
