Gossip-based service coordination for scalability and resilience

Many interesting emerging applications involve the coordination of a large number of service instances, for instance, as targets for dissemination or sources in information gathering. These applications raise hard architectural, scalability, and resilience issues that are not suitably addressed by centralized or monolithic coordination solutions. In this paper we propose a lightweight approach to service coordination aimed at such application scenarios. It is based on gossiping and thus potentially fully decentralized, requiring that each participant is concerned only with a small number of peers. Although being obviously simple and scalable, it has been shown that gossip-based protocols lead to emergent strong resilience guarantees. We illustrate the approach with WS--PushGossip, a proof-of-concept coordination protocol based upon the WS--Coordination framework. Besides presenting WS--PushGossip, we illustrate its usefulness with a sample application, and outline a middleware implementation based on Apache Axis2.(undefined

Improving the Scalability of DPWS-Based Networked Infrastructures

The Devices Profile for Web Services (DPWS) specification enables seamless discovery, configuration, and interoperability of networked devices in various settings, ranging from home automation and multimedia to manufacturing equipment and data centers. Unfortunately, the sheer simplicity of event notification mechanisms that makes it fit for resource-constrained devices, makes it hard to scale to large infrastructures with more stringent dependability requirements, ironically, where self-configuration would be most useful. In this report, we address this challenge with a proposal to integrate gossip-based dissemination in DPWS, thus maintaining compatibility with original assumptions of the specification, and avoiding a centralized configuration server or custom black-box middleware components. In detail, we show how our approach provides an evolutionary and non-intrusive solution to the scalability limitations of DPWS and experimentally evaluate it with an implementation based on the the Web Services for Devices (WS4D) Java Multi Edition DPWS Stack (JMEDS).Comment: 28 pages, Technical Repor