Architecture of monitoring elements for the network element modeling in a Grid infrastructure

Several tools exist that collect host-to-host connectivity measurements. To improve the usability of such measurements, they should be mapped into a framework consisting of complex subsystems, and the infrastructure that connects them. We introduce one such framework, and analyze the architectural implications on the network structure. In our framework, a complex subsystem consists of several computing facilities and the infrastructure that connects them: we call it a -monitoring domain-. The task of measuring the connectivity between -monitoring domains- is considered distinct from the activity of -storage- and -computing- elements. Therefore we introduce a new element in our topology: we call it -theodolite- element, since its function is similar to that of a transponder. Using these basic concepts, we analyze the architectural implications on the network structure: in a nutshell, if we want that -theodolites- serve as a reference, than the contribution to the relevant network metrics due to the -monitoring domain- infrastructure must be negligible with respect to contributions of the inter-domain infrastructure. In addition all -theodolites- of a -monitoring domain- must give an image of the inter-domain infrastructure that is consistent with that experienced by network applications. We conclude giving a running SQL example of how information about -monitoring domains- and -theodolites- could be organized, and we outline the application of such framework in the GLUE schema activity for the network element