Standard and cross-domain RSLs are RSLs that you create from your custom component libraries. These RSLs are different from signed framework RSLs in that they are unsigned and can only be stored in the browser's cache. They are never stored in the Player cache.

To use standard or cross-domain RSLs, you perform the following tasks:

• Create a library An RSL is created from a library of custom classes and other assets. You can create a library with either the Flex Builder Library Project or the compc command-line compiler. You can output the library as a SWC file or an open directory. The library includes a library.swf file and a catalog.xml file; the library.swf file is deployed as the RSL. For more information, see Creating libraries.

• Compile your application against the library When you compile your Flex application, you externalize assets from your application that are defined in the RSL. They can then be linked at run time rather than at compile time. You do this when you compile the application by passing the compile-time location of the library SWC file as well as the run-time location of the library's SWF file. For more information, see Compiling applications with standard and cross-domain RSLs.

• Optimize the RSL After you generate a library and compile your application against it, you should run the optimizer against the library's SWF file. The optimizer reduces the SWF file by removing debugging code and unneeded metadata from it. While this step is optional, it is best practice to optimize a library SWF file before deploying it. For more information, see Optimizing RSL SWF files.

• Deploy the RSL After you have compiled and optionally optimized your RSL, you deploy the library.swf file with your application so that it is accessible at run time. If the RSL is a cross-domain RSL, then you might also be required to deploy a crossdomain.xml file.