iSIS is only a core engine written in PHP to help transform any number of MySQL databases (remote or local) and your webserver into a streaming server. So in effect, your webserver is the frontend and you stream your files using a MySQL server to all your users.
Therefore what you have is,
Your Webserver(1) + n. no. of MySQL database/servers + iSIS(core) = iSIS streaming server.
Then you can stream in any of your websites like this,
Your Webserver(1,2,3) + iSIS (client files) <-> your client web pages= Streaming media website.
You may enhance your iSIS setup and the website by using additional modules.
Following File Releases are available under downloads.
boxfiles - The core setup and developer files
add-modules - Extra modules for iSIS, client & webserver
user-mods - user submitted modules.