1. Architecture of monitoring elements for the network element modeling in a Grid infrastructure Authors: Augusto Ciuffoletti Tiziana Ferrari Antonia Ghiselli Cristina Vistoli Presenter: Sergio Andreozzi INFN-CNAF Bologna (Italy) sergio.andreozzi@cnaf.infn.it

2. CHEP 2003 - March, 27 2003 2 OUTLINE The context of this proposal Motivations Terms and concepts Diagram and examples

3. CHEP 2003 - March, 27 2003 3 The context of this work Promoted by INFN-CNAF (Bologna, Italy) Currently discussed in both: – GLUE (Grid Laboratory Uniform Environment) context: collaboration effort promoted by DataTAG and iVDGL projects focusing on interoperability between US and EU HENP Grid middlewares GLUE Schema for the Grid Information Service – GGF NM-WG

4. CHEP 2003 - March, 27 2003 4 MOTIVATIONS A (Grid) computation requires three kinds of resources: – Storage, Computing, and Communication resources Grid aware applications need to know the characteristics of such resources, in order to setup their execution environment Modeling communication resources needs some simplifying assumption in order to decrease the N 2 complexity of the interconnection structure – we want to model differentiated services; – we want to describe (and control) the measurement infrastructure.

5. CHEP 2003 - March, 27 2003 5 Partitioning the Grid into network domains – Services can be organized into network domains on the base of the quality of the connection – Communication bottlenecks should materialize between domains – From the viewpoint of a grid-aware computation, only communication between domains should be permanently monitored – Still N 2 complexity, but now N is related to the number of domains

6. CHEP 2003 - March, 27 2003 6 Terms and concepts Edge Service, Connectivity and Network Domain Edge Service: service that uses or monitor the communication infrastructure; Connectivity:is a metric that reflects the quality of communication through a path between two Edge Services Network Domain: – identified by a URI – disjointed set of edge services – it communicates with other (network) domains using network services – it is said to be qualified if its internal connectivity is estimated higher than that of any adjacent Network Service.

7. CHEP 2003 - March, 27 2003 7 Terms and concepts Network Service Network Services: – offers unidirectional communication between two domains – it is characterized by several characteristics – since these characteristics are dynamics, each of them is associated to an observation ( instance of the information obtained by applying the measurement methodology ) – Characteristics are one-way, but the presence of two- way characteristics can be accommodated when necessary as an approximation of the one-way ones

8. CHEP 2003 - March, 27 2003 8 Terms and concepts Theodolite service Theodolite service: – it observes the characteristics of the communication infrastructure – it offers a method for on-demand observation – it should be placed near an access points of a Domain, so that it measures the quality of the infrastructure between its domain and the connected ones

9. CHEP 2003 - March, 27 2003 9 Facing temporary or permanent inconsistencies of domains D: CERN D: INFN-CNAF VLAN – Lev 2 D: CNAF-CERN

10. CHEP 2003 - March, 27 2003 10 The UML Class Diagram

11. CHEP 2003 - March, 27 2003 11 REFERENCE DataTAG Project – http://www.datatag.org Grid Laboratory Uniform Environment (GLUE) DataTAG WP4 and iVDGL Interoperability Group version 0.1.2 – http://www.hicb.org/glue/glue-v0.1.2.doc http://www.hicb.org/glue/glue-v0.1.2.doc GLUE Schema for the Network Element – http://www.di.unipi.it/~augusto/gluedomains/ GLUE Schema for Computing and Storage Elements – http://www.cnaf.infn.it/~sergio/datatag/glue