Although Tasker is a simple app, we've built it to mirror a typical enterprise setup, as shown in the following diagram:

The mobile device (say, the user's phone) is considered the presentation tier of the app; this is where the data is displayed to the user and where they can manipulate it. Although this book is a PhoneGap book, we actually won't deal with this tier until Chapter 5, Communicating between Mobile and the Middle Tier, and later, since we need to establish the foundation of the app first.

The mobile device doesn't have to live on the enterprise's network. Depending on the sensitivity of the data, the mobile device might be expected to connect to the enterprise's network using a Virtual Private Network (VPN). This essentially means that the device exists within the enterprise's network. Since this adds an extra burden on the user (they need to connect to the VPN prior to using the app), this isn't always desirable. For this reason, we've built our app under...