Harshawardhan Gadgil

A Framework for Secure End-to-End Delivery of Messages in Publish/Subscribe Systems

In this paper, we present a framework for the secure end-to-end delivery of messages in distributed messaging infrastructures based on the publish/subscribe paradigm. The framework enables authorized publishing and consumption of messages. Brokers, which constitute individual nodes within the messaging infrastructure, also ensure that the dissemination of content is enabled only for authorized entities. The framework includes strategies to cope with attack scenarios such as denial of service attacks and replay attacks. Finally, we include experimental results from our implementation

Building messaging substrates for Web and Grid applications

Grid application frameworks have increasingly aligned themselves with the developments in Web services. Web services are currently the most popular infrastructure based on service-oriented architecture (SOA) paradigm. There are three core areas within the SOA framework: (i) a set of capabilities that are remotely accessible, (ii) communications using messages and (iii) metadata pertaining to the aforementioned capabilities. In this paper, we focus on issues related to the messaging substrate hosting these services; we base these discussions on the NaradaBrokering system. We outline strategies to leverage capabilities available within the substrate without the need to make any changes to the service implementations themselves. We also identify the set of services needed to build Grids of Grids. Finally, we discuss another technology, HPSearch, which facilitates the administration of the substrate and the deployment of applications via a scripting interface. These issues have direct relevance to scientific Grid applications, which need to go beyond remote procedure calls in client-server interactions to support integrated distributed applications that couple databases, high performance computing codes and visualization codes.

SERVOGrid complexity computational environments (CCE) integrated performance analysis

In this paper we describe the architecture and initial performance analysis results of the SERVOGrid complexity computational environments (CCE). The CCE architecture is based on a lightly coupled, service oriented architecture approach that is suitable for distributed applications that are tolerant of Internet latencies. CCE focuses on integrating diverse Web and grid services for coupling scientific applications to geographical information systems. The services and coupling/orchestrating infrastructure are mapped to problems in geophysical data mining, pattern informatics, and multiscale geophysical simulation.

Management of real‐time streaming data Grid services

We discuss our message‐based approach to managing real‐time data streams and building higher level services to produce and consume them. Our messaging system acts as a substrate that can be used to provide qualities of service to various streaming applications ranging from audio–video collaboration systems to sensor Grids. The messaging substrates are composed of distributed, hierarchically arranged message broker networks. Services such as filters are deployed along the edges of the network. We discuss the role of management systems for both broker networks and filter services: broker network topologies must be created and maintained, and distributed filters must be arranged in appropriate sequences. These managed broker networks may be applied to a wide range of problems. We discuss applications to audio–video collaboration in some detail and also describe applications to streaming Global Positioning System data streams. These provide specific application filters that can transform and republish message streams to the broker system. Copyright

On the creation & discovery of topics in distributed publish/subscribe systems

Publish/subscribe infrastructures have in the recent years gained significant traction with several specifications such as the Java Message Service, WS-Eventing and WS-Notification trying to capture the essence of publish/subscribe systems and enabling the development of interoperable systems. In this paper we present a scheme for the discovery of topics in distributed publish/subscribe systems. The scheme outlined in this paper addresses security related issues such as authorization and provenance in the discovery of the aforementioned topics. We have also included results from our implementation of this scheme to demonstrate the feasibility of this mechanism. The work that we describe here can be used in systems based on JMS, WS-Eventing or WS-Notification.

On the Discovery of Brokers in Distributed Messaging Infrastructures

Increasingly messaging infrastructures are being used to support the communication requirements of a wide variety of clients, services, and proxies thereto. Typically, for various reason this messaging infrastructure is a distributed one with multiple constituent brokers. In the paper we present our scheme for the discovery of brokers in distributed messaging infrastructures based on the publish/subscribe paradigm. We also include empirical results from our experiments related to the implementation of our scheme

A scripting based architecture for management of streams and services in real-time grid applications

Recent specifications such as WS-management and WS-distributed management have stressed the importance of management of resources and services and propose methods towards querying Web services to gather the meta-data associated with these services. Management often entails system setup, querying system metadata, manipulation of system parameters at runtime and taking actions based on the system parameters to tune system performance. Real-time applications require rapid deployment of application components and demand results in real time. In this paper we present the HPSearch system which enables dynamic management of the system including both streams and Web services, and rapid deployment of applications via a scripting interface. We illustrate the functioning of the system by modeling a data streaming application and rapidly deploying the system and application components.

Scalable, fault-tolerant management in a service oriented architecture

The service-oriented architecture has come a long way in solving the problem of reusability of existing software resources. Grid applications today are composed of a large number of loosely coupled services. While this has opened up new avenues for building large, complex applications, it has made the management of the application components a non-trivial task. Management is further complicated when services exist on different platforms, are written in different languages, present in varying administrative domains restricted by firewalls and are susceptible to failure. This paper investigates problems that emerge when there is a need to uniformly manage a set of distributed services. We present a scalable, fault-tolerant management framework. Our empirical evaluation shows that the architecture adds an acceptable number of additional resources making the approach feasible.

Managing grid messaging middleware

Management in distributed systems has gained much importance in recent years. With the increasing complexity of applications, there is a need for effective management of components of the application. As application components span different administrative domains, differing security policies restrict access to these components. The problem gets more complicated in a dynamic environment where application components and the environment is in a constant state of flux, so that failure is the norm. In this paper we explore the issues related to management in dynamic and heterogeneous environments. We propose a scalable, fault-tolerant and Web services - compliant management architecture that addresses these issues of management and also illustrate the functioning of our framework with respect to the NaradaBrokering messaging middleware

Management of real-time streaming data grid services

We discuss the architectural and management support for real time data stream applications, both in terms of lower level messaging and higher level service, filter and session structures. In our approach, messaging systems act as a Grid substrate that can provide qualities of service to various streaming applications ranging from audio-video collaboration to sensor grids. The messaging substrate is composed of distributed, hierarchically arranged message brokers that form networks. We discuss approaches to managing systems for both broker networks and application filters: broker network topologies must be created and maintained, and distributed filters must be arranged in appropriate sequences. These managed broker networks may be applied to a wide range of problems. We discuss applications to audio/video collaboration in some detail and also describe applications to streaming Global Positioning System data streams.