The deployment of a Silverlight application that utilizes Telerik Reporting can be divided in three steps:
Deploying the Silverlight report viewer: All referenced assemblies in the Silverlight application are embedded at compile time into the XAP file, which should be deployed along with the application that hosts the Silverlight application.
Deploying the Telerik Reporting WCF Service: As the Silverlight report viewer uses the Telerik Reporting WCF Service to access the Telerik Reporting Engine, you should deploy (Telerik.Reporting.Service.dll) with the application that hosts the WCF service.
Deploying the Telerik Reporting Engine: The Reporting engine (Telerik.Reporting.dll) should be deployed along with the application that hosts the Telerik Reporting WCF Service.
These assemblies add up to the Telerik Reporting Engine functionality and should be used only if you need the specific feature. They are responsible for additional support formats, database cache or retrieving data from an OLAP cube. The asseblies must be deployed along with the application that hosts the Telerik Reporting WCF Service.
XPS rendering extension requires Telerik.Reporting.XpsRendering assembly (Telerik.Reporting.XpsRendering.dll).
DOCX/PPTX/XLSX rendering extensions require Telerik.Reporting.OpenXmlRendering.dll and Open XML SDK 2.0 for Microsoft Office (DocumentFormat.OpenXml.dll v.2.0.5022.0 or above with proper binding redirect).
Database Cache Provider requires Telerik.Reporting.Cache.Database.dll and Telerik Data Access.