ReportServer provides support in creating drill down and drill across reports with Jasper- Reports and BIRT. For Drill Down and Drill Across operations, reports will be linked with each other to show more detailed information on specified data. ReportServer provides the special parameters _RS_BACKLINK_ID und _RS_BACKLINK_URL to each report execution . So when you are in a JasperReport and you want to link it to the report with the key myKey enter the link as follows:

"http://localhost:8888/reportserver/reportserver/reportexport?key=myKey&" 
+ "format=html&bid=" + $P{_RS_BACKLINK_ID}

Of course, you have to replace the first part of the link by the server address. By entering the parameter bid you can easily set a backlink. You will get the required URL via the parameter _RS_BACKLINK_URL. If there is no backlink, the parameter will be empty.