Quality of services for remote control in High Energy Physics experiments: a case study

Abstract The development of new advanced applications and the evolution in networking are two related processes which greatly benefit from two-way exchanges and from progress in both fields. In this study we show how mission-oriented networked applications can be effectively deployed for research purposes if coupled to the support of Quality of Service (QoS) in IP networks. QoS is one of the latest research topics in network engineering. In this article we focus on two specific examples of networked applications: remote instrumentation control and remote display of analysis data when applied for the support of experiments in the high energy physics field. In this paper we focus on the application requirements: the availability of a reliable transmission channel, limited one-way delay for timely interactions between servers and clients and fairness in network resources allocation in case of contention. The above-mentioned requirements can be addressed through the support of QoS, i.e. through the differential treatment of packets on the end-to-end data path. Several technologies and protocols for QoS support in packet networks have been devised during the last years by the research community. In this study we focus on the Differentiated Services (diffserv) approach, an architecture characterized by high scalability, flexibility and interoperability. In this paper we identify the application requirements and we quantitatively specify the corresponding service profiles. The diffserv network architecture needed to support the services is defined in terms of functional blocks (policing, classification, marking and scheduling) and of their placement in the network. Finally, for each of them the configuration best suited to remote control support is defined

The INFN-grid testbed

The Italian INFN-Grid Project is committed to set-up, run and manage an unprecedented nation-wide Grid infrastructure. The implementation and use of this INFN-Grid Testbed is presented and discussed. Particular care and attention are devoted to those activities, relevant for the management of the Testbed, carried out by the INFN within international Grid Projects

Issues about the Integration of Passive and Active Monitoring for Grid Networks

SUMMARY In this paper we discuss the issues arising with the integration of passive and active monitoring techniques for Grid network infrastructure monitoring. Our proposal is related to the monitoring information production and publication. Initially, we present the context of our work within the Grid world. We enlist the range of different techniques to perform measurements and obtain monitoring data. We propose a number of interesting performance metrics of the quality of the Grid infrastructure connectivity, and the related passive and active monitoring techniques that are required in order to obtain these metrics

Monitoring the connectivity of a Grid

Grid computing is a new paradigm that enables the distributed coordination of resources and services which are geographically dispersed, span multiple trust domains and are heterogeneous. Network infrastructure monitoring, while vital for activities such as service selection, exhibits inherent scalability problems: in principle, in a Grid composed of n resources, we need to keep record of n2 end-to-end paths. We introduce an approach to network monitoring that takes into account scalability: a Grid is partitioned into domains, and network monitoring is limited to the measurement of domain-to-domain connectivity. However, partitions must be consistent with network performance, since we expect that an observed network performance between domains is representative of the performance between the Grid Services included into domains

A PRACTICAL APPROACH FOR A WORKFLOW MANAGEMENT SYSTEM

Abstract A variety of grid middlewares and workflow languages causes the existence of many workflow management systems (WfMS). Formalisms used to represent workflows vary from simple Directed Acyclic Graphs (DAG) to more complex (non deterministic) Petri Nets. Therefore a workflow description is strictly bound to a particular WfMS and to the computational resources that WfMS address, as far as no cooperation among WfMSs exists. This might be critical in scientific workflows where a large amount of resources is usually needed. In this paper we propose a WfMS that aims at language independence and Grid middleware abstraction dealing with interoperability as proposed in the reference model of the Workflow Management Coalition (WfMC). The main goal of such WfMS is to provide an effective solution to run complex scientific workflows (legacy or not) taking full advantage of the distributed and etherogeneous nature of the Grid. A Petri Net formalism has been chosen as internal representation due to its formal behavioral description and the existence of several analysis tools. Our proposed WfMS will be implemented on top of the gLite Grid middleware provided by the EGEE project because of its stability and large adoption. Keywords: workflow management, grid computing, interoperability, Petri Net, EGEE/gLite 1

Gluedomains: Organization and accessibility of network monitoring data in a grid

The availability of the outcome of network monitoring activities, while valuable for the operation of Grid applications, poses serious scalability problems: in principle, in a Grid composed of n resources, we need to keep record of n 2 end-to-end paths. We introduce a scalable approach to network monitoring, that consists in partitioning the Grid into Domains, limiting monitoring activity to the measurement of Domain-to-Domain connectivity. Partitions must be consistent with network performance, since we expect that an observed network performance between Domains is representative of the performance between the Grid Services included into such Domains. We argue that partition design is a critical step: a consequence of an inconsistent partitioning is the production of invalid characteristics. The paper discusses such approach, also exploring its limits. We describe a fully functional prototype which is currently under test in the frame of the DATATAG project