Exploiting the Synergy Between Gossiping and Structured Overlays

In this position paper we argue for exploiting the synergy between gossip-based algorithms and structured overlay networks (SON). These two strands of research have both aimed at building fault-tolerant, dynamic, self-managing, and large-scale distributed systems. Despite the common goals, the two areas have, however, been relatively isolated. We focus on three problem domains where there is an untapped potential of using gossiping combined with SONs. We argue for applying gossip-based membership for ring-based SONs---such as Chord and Bamboo---to make them handle partition mergers and loopy networks. We argue that small world SONs---such as Accordion and Mercury---are specifically well-suited for gossip-based membership management. The benefits would be better graph-theoretic properties. Finally, we argue that gossip-based algorithms could use the overlay constructed by SONs. For example, many unreliable broadcast algorithms for SONs could be augmented with anti-entropy protocols. Similarly, gossip-based aggregation could be used in SONs for network size estimation and load-balancing purposes

Optimization of DEECo gossip-based communication

Rozšiřování velkého počtu bezdrátových zařízení dalo podnět ke vzniku komponentového modelu DEECo určeného pro aplikace, jejichž neoddělitelnou součástí je mobilita a dynamická kompozice s architekturou vytvářenou za běhu. Velkou výzvou při realizaci takového systému je návrh komunikačního systému založeném na gossip protokolu. Takové řešení je zvlášť vhodné pro sítě typu MANET a jeho účelem je zvýšení spolehlivosti. V této práci jsme navrhli optimalizaci protokolu s využitím vlastností sítě s vlastní infrastrukturou. Zachovali jsme při tom gossip způsob komunikace bez zavedení centralizovaného prvku. Navrhované zlepšení spočívá ve vytvoření komunikačních skupin zformovaných na úrovni návrhu. Experimenty ukázaly podstatný pokles počtu odeslaných zpráv a celkově snížený čas doručení. Problematiku časování jsme pak zvlášť zpracovali pro MANET sítě a implementovali jsme mechanizmus pullování, který významně snížil latenci. Část této práce je věnována formální specifikaci sémantiky za účelem přesného zdůvodnění vlastností systému, čímž jsme také položili základ pro další rozšíření protokolu a budoucí výzkum v oblasti distribuovaných systémů. Powered by TCPDF (www.tcpdf.org)The spread of wireless devices inspired the creation of a DEECo component model suitable for designing applications with immanent mobility and dynamic composition where the system architecture emerges at runtime. A great challenge in implementation of such a system is the underlying communication mechanism based on gossip protocol in order to achieve resilience and suitability for MANET networks. In this thesis we propose an optimization of the protocol exploiting infrastructure networks, but still preserving the gossip-like communication without a centralized element. The improvement is based on forming communication groups introduced at the design level. The experiments show a substantial decrease in the number of sent messages and a decrease in time of data delivery. The timing aspect of data delivery is further elaborated for MANET networks by implementing a pulling mechanism with significant improvement of the latency. Part of this thesis is dedicated to a formal specification of the system semantic to provide a precise rationale about its properties and laying the ground for further extensions and research. Powered by TCPDF (www.tcpdf.org)Department of Distributed and Dependable SystemsKatedra distribuovaných a spolehlivých systémůMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

Exploiting the Synergy Between Gossiping and Structured Overlays

ali(at)sics.se In this position paper we argue for exploiting the synergy between gossip-based algorithms and structured overlay networks (SON). These two strands of research have both aimed at building fault-tolerant, dynamic, self-managing, and largescale distributed systems. Despite the common goals, the two areas have, however, been relatively isolated. We focus on three problem domains where there is an untapped potential of using gossiping combined with SONs. We argue for applying gossip-based membership for ring-based SONs—such as Chord and Bamboo—to make them handle partition mergers and loopy networks. We argue that small world SONs—such as Accordion and Mercury—are specifically well-suited for gossip-based membership management. The benefits would be better graph-theoretic properties. Finally, we argue that gossip-based algorithms could use the overlay constructed by SONs. For example, many unreliable broadcast algorithms for SONs could be augmented with anti-entropy protocols. Similarly, gossip-based aggregation could be used in SONs for network size estimation and loadbalancing purposes