Abstract
A close co-operation between WP1 (Workload Management) and WP2 (Data Management) of the EU DataGrid project is necessary for the realisation of a Replica Optimisation Framework. The purpose of the present document is to amalgamate the visions that WP1 and WP2 have on such a framework and to define its features. We define an API for the replica optimiser called Optor, whose functions are called by WP1 software or by a running job in order to optimise data access. In addition, we define APIs required from WP5 and WP7 to get information concerning performance data.