649 research outputs found
VCube-PS: A Causal Broadcast Topic-based Publish/Subscribe System
In this work we present VCube-PS, a topic-based Publish/Subscribe system
built on the top of a virtual hypercube-like topology. Membership information
and published messages are broadcast to subscribers (members) of a topic group
over dynamically built spanning trees rooted at the publisher. For a given
topic, the delivery of published messages respects the causal order. VCube-PS
was implemented on the PeerSim simulator, and experiments are reported
including a comparison with the traditional Publish/Subscribe approach that
employs a single rooted static spanning-tree for message distribution. Results
confirm the efficiency of VCube-PS in terms of scalability, latency, number and
size of messages.Comment: Improved text and performance evaluation. Added proof for the
algorithms (Section 3.4
Bundling Messages to Reduce the Cost of Tree-Based Broadcast Algorithms
International audienceHierarchical broadcast strategies based on trees are scalable since they distribute the workload among processes and disseminate messages in parallel. In this work we propose an efficient best-effort broadcast algorithm that employs multiple spanning trees to propagate messages that are bundled on tree intersections. The algorithm is autonomic in the sense that it employs dynamic trees rooted at the source process and which rebuild themselves after processes crash. Experimental results obtained with simulation are presented showing the performance to the algorithm in terms of the latency and the number and sizes of messages employed
Broadcasting methods in mobile ad hoc networks: Taxonomy and current state of the art
Flooding also known as broadcasting is one of the most primitive methodologies that focus on investigating searches concerning mobile ad hoc networking due to poorer network procedures which is a main feature in the concept of broadcasting which provides implications to superior applications that includes routing. Broadcasting means in conventional ways transmitting messages from a given branch to all other branches present in a network. The whole grid of the network is manned to ensure that the transmitted data is uniformly ported to the remaining nodes in a decentralized type of network setup. The two issues that renders nodes out of reach all the time are limited radio range and their immovability which assists in concluding that te issue of data transmission covering all networks is assumed to be a multi-objective issue that aims at increasing the count of number of nodules and also decreasing the time taken to reach the specified nodules and also reducing the network overhead which is a crucial characteristic because of the fact that this may direct to congestion also known as broadcast storm issue. This article aims at giving an insight of the taxonomy of transmitting methodologies in MANETS and current state of the art
Agreement in epidemic data aggregation
Computing and spreading global information in large-scale distributed systems pose significant challenges when scalability, parallelism, resilience and consistency are demanded. Epidemic protocols are a robust and scalable computing and communication paradigm that can be effectively used for information dissemination and data aggregation in a fully decentralised context where each network node requires the local computation of a global synopsis function. Theoretical analysis of epidemic protocols for synchronous and static network models provide guarantees on the convergence to a global target and on the consistency among the network nodes. However, practical applications in real-world networks may require the explicit detection of both local convergence and global agreement (consensus). This work introduces the Epidemic Consensus Protocol (ECP) for the determination of consensus on the convergence of a decentralised data aggregation task. ECP adopts a heuristic method to locally detect convergence of the aggregation task and stochastic phase transitions to detect global agreement and reach consensus. The performance of ECP has been investigated by means of simulations and compared to a tree-based Three-Phase Commit protocol (3PC). Although, as expected, ECP exhibits total communication costs
greater than the optimal tree-based protocol, it is shown to have better performance and scalability properties; ECP can achieve faster convergence to consensus for large system sizes and inherits the intrinsic decentralisation, fault-tolerance and robustness properties of epidemic protocols
04411 Abtracts Collection -- Service Management and Self-Organization in IP-based Networks
From 03.10.04 to 06.10.04,
the Dagstuhl Seminar
04411 ``Service Management and Self-Organization in IP-based Networks\u27\u27 was held
in the International Conference and Research Center (IBFI), Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available
Software Defined Networks based Smart Grid Communication: A Comprehensive Survey
The current power grid is no longer a feasible solution due to
ever-increasing user demand of electricity, old infrastructure, and reliability
issues and thus require transformation to a better grid a.k.a., smart grid
(SG). The key features that distinguish SG from the conventional electrical
power grid are its capability to perform two-way communication, demand side
management, and real time pricing. Despite all these advantages that SG will
bring, there are certain issues which are specific to SG communication system.
For instance, network management of current SG systems is complex, time
consuming, and done manually. Moreover, SG communication (SGC) system is built
on different vendor specific devices and protocols. Therefore, the current SG
systems are not protocol independent, thus leading to interoperability issue.
Software defined network (SDN) has been proposed to monitor and manage the
communication networks globally. This article serves as a comprehensive survey
on SDN-based SGC. In this article, we first discuss taxonomy of advantages of
SDNbased SGC.We then discuss SDN-based SGC architectures, along with case
studies. Our article provides an in-depth discussion on routing schemes for
SDN-based SGC. We also provide detailed survey of security and privacy schemes
applied to SDN-based SGC. We furthermore present challenges, open issues, and
future research directions related to SDN-based SGC.Comment: Accepte
Practical Aggregation in the Edge
Due to the increasing amounts of data produced by applications and devices, cloud infrastructures
are becoming unable to timely process and provide answers back to users.
This has led to the emergence of the edge computing paradigm that aims at moving
computations closer to end user devices. Edge computing can be defined as performing
computations outside the boundaries of cloud data centres. This however, can be materialised
across very different scenarios considering the broad spectrum of devices that can
be leveraged to perform computations in the edge.
In this thesis, we focus on a concrete scenario of edge computing, that of multiple
devices with wireless capabilities that collectively form a wireless ad hoc network to perform
distributed computations. We aim at devising practical solutions for these scenarios
however, there is a lack of tools to help us in achieving such goal. To address this first
limitation we propose a novel framework, called Yggdrasil, that is specifically tailored to
develop and execute distributed protocols over wireless ad hoc networks on commodity
devices.
As to enable distributed computations in such networks, we focus on the particular
case of distributed data aggregation. In particular, we address a harder variant of this
problem, that we dub distributed continuous aggregation, where input values used for
the computation of the aggregation function may change over time, and propose a novel
distributed continuous aggregation protocol, called MiRAge.
We have implemented and validated both Yggdrasil and MiRAge through an extensive
experimental evaluation using a test-bed composed of 24 Raspberry Pi’s. Our results
show that Yggdrasil provides adequate abstractions and tools to implement and execute
distributed protocols in wireless ad hoc settings. Our evaluation is also composed of a
practical comparative study on distributed continuous aggregation protocols, that shows
that MiRAge is more robust and achieves more precise aggregation results than competing
state-of-the-art alternatives
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