Abstract

Computer technology for communication has become an integral aspect of daily operation. The exponential growth of internet services with dynamic inquiries in such areas as manufacturing, business, air traffic control and mission critical systems demands that there be quick, reliable and safe use of services. Each service must contain QoS metrics to assure security, performance and accuracy. A new paradigm of resource management middleware techniques is in this paper presented which can provide QoS for dynamic, distributed real-time systems on Common Off The Shelf (COTS) operating systems. Accommodation of dynamic environments enables the middleware to carefully consider an efficient design of resource profiling, resource needs estimation, resource unification, and performance analysis (or compliant with schedulability analysis) infrastructure providing significant benefits for QoS management on COTS operating systems. First, the use of low-cost COTS systems is extended to real-time computing without changing the operating system. Further, experiments for response time analysis confirm that the worst-case analysis poorly utilizes computational resources. Finally, it is shown that the new method of middleware design employing scalability of software and hardware system can be easily applied to legacy systems to manage resources efficiently for quick, reliable services and accurate QoS. Document type: Part of book or chapter of book

Abstract

International audience; Mobility and security are major features for both current and future network infrastructures. Nevertheless, the integration of mobility in traditional virtual private networks is difficult due to the costs of re-establishing broken secure tunnels and restarting broken connections. Besides session recovery costs, renegotiation steps also present inherent vulnerabilities. In order to address these issues, we propose a new distributed mobile VPN system called SEcured MObile Session (SEMOS). Based upon our CLOAK peer-to-peer overlay architecture, SEMOS provides security services to the application layer connections of mobile users. Secure and resilient sessions allow user connections to survive network failures as opposed to regular transport layer secured connections used by traditional VPN protocols. Document type: Part of book or chapter of book

Abstract

The design of large-scale critical infrastructures demands for innovative data dissemination services, able to jointly provide reliability and timeliness guarantees. Current middleware solutions do not address both these aspects. Indeed, fault tolerance is typically achieved at the cost of severe performance fluctuations, or timeliness is always obtained by softening the fault-tolerance requirements. In this paper we propose to fulfill this lack by combining two different approaches, namely coding and gossiping. We provide a theoretical model to evaluate the potential benefit of coding on the information delivery performance. These results are also confirmed by an experimental analysis conducted on a real air traffic control workload, which evidences how coding mitigates latency and overhead penalties to ensure reliable event notification. Document type: Part of book or chapter of book

Abstract

This paper presents congestion control mechanisms for reliable and scalable message-oriented middleware following the publish/subscribe communication model. We identify the key requirements of congestion control in this environment, how it differs from congestion control for the Internet, and propose a combination of two congestion control mechanisms, (1) driven by a publisher hosting broker (PDCC), (2) driven by a subscriber hosting broker (SDCC). SDCC decouples the notion of a receive window and a NACK window, and is used by subscriber hosting brokers in recovery mode. PDCC implements a scalable and low latency feedback loop between a publisher hosting broker and all subscriber hosting brokers, which is used to adjust the rate of publishing new messages, to allow brokers in recovery to eventually catch up, and other brokers to keep up. We present a detailed experimental evaluation of our implementation of these mechanisms in the Gryphon system by injecting network failures and link congestion. Document type: Part of book or chapter of book