Data center models are changing. A variety of technical trends and business demands are forcing that change, most of them centered on the explosive growth of applications. That means, in turn, that the requirements for application delivery are changing.
Certainly application delivery needs to be agile, not waterfall. It needs to deliver services in hours, not weeks or months. It needs to be more cost efficient. And more than anything else, it needs to be really, dc infra axisreally, super focused on applications. Especially those services that are particularly application affine. You know the ones - caching, load balancing, web app security, and performance. These are the services whose configurations are tied (tightly coupled) to the applications they deliver. Thus, they need to be closer to the app. Topologically if not physically.