Agile Enterprise Application Development with Flex

It Takes Two to Perform

Fast applications are your goal, but how do you get there? On one hand, the RIA deployed on the server should consist of a number of relatively small .swf, .swc, and asset files. On the other, ideally, the end users should use fast and reliable network connections. First, let’s define how fast your RIA should appear, and then we’ll look at how quickly the data arrives to the user’s machine.

The major difference between an internal enterprise and a consumer-facing RIA is that the former runs on fast and reliable networks with predictable speed and the latter runs in a Wild West with unknown bandwidth. You have to set the proper expectations of your RIA download speed from the very start. To do that you need an SLA.

SLA stands for service level agreement, and the stakeholders of your project should sign off on an agreement that states the acceptable delivery speed of your application and data. If your application will run on, say, a 15 Mbps intranet, the main page of the application should appear in less than about 7 seconds. If yours is a consumer-facing application, you can reasonably expect that the users have a network connection with 1 Mbps bandwidth. To put yourself into their shoes, run special tests emulating such a slow speed; for example, you could use the HTTP proxy and monitor Charles (see the sidebar Troubleshooting with Charles in Chapter 4) or a hardware network emulator. To keep initial response time for the application, you need to make sure ...