A Front End script is a script-only application that uses the Microsoft SIP Processing Language (MSPL) scripting language instead of the Office Communications Server API. MSPL provides more granular control over filtering and proxy behaviors, as well as a facility for dispatching specific messages to transaction-based SIP applications. MSPL is used specifically for filtering and routing SIP messages. MSPL applications run in the same process as the UserServices module, while a program that is based on the RTC API runs in a separate process. To add a Front End script, you specify the following:

For details, see the Microsoft Office Communications Server 2007 R2 SDK at http://go.microsoft.com/fwlink/?LinkID=126309 .