Semi-fluid: A Content Distribution Model For Faster Dissemination Of Data

Tesis ini mencadangkan serta melaksanakan suatu model agihan kandungan bagi mengurangkan atau meminimumkan kelengahan penyaluran data sebaya. Buat masa ini, agihan kandungan dalam rangkaian tindihan-atas adalah berdasarkan dua model berikut: model Kelulan dan model Bendalir. This thesis proposes and implements a novel content distribution model for reducing or minimizing delay in data dissemination

Worst-case delay control in multigroup overlay networks

This paper proposes a novel and simple adaptive control algorithm for the effective delay control and resource utilization of end host multicast (EMcast) when the traffic load becomes heavy in a multigroup network with real-time flows constrained by (sigma, rho) regulators. The control algorithm is implemented at the overlay networks and provides more regulations through a novel (sigma, rho, lambda) regulator at each group end host who suffers from heavy input traffic. To our knowledge, it is the first work to incorporate traffic regulators into the end host multicast to control heavy traffic output. Our further contributions include a theoretical analysis and a set of results. We prove the existence and calculate the value of the rate threshold rho* such that for a given set of K groups, when the average rate of traffic entering the group end hosts rho macr > rho*, the ratio of the worst-case multicast delay bound of the proposed (sigma, rho, lambda) regulator over the traditional (sigma, rho) regulator is O(1/Kn) for any integer n. We also prove the efficiency of the novel algorithm and regulator in decreasing worst-case delays by conducting computer simulations

An active protocol architecture for collaborative media distribution

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2002.Includes bibliographical references (p. 107-114).This thesis embarks on distributing the distribution for real-time media, by developing a decentralized programmable protocol architecture. The core of the architecture is an adaptive application-level protocol which allows collaborative multicasting of real-time streams. The protocol provides transparent semantics for loosely coupled multipoint interactions. It allows aggregation and interleaving of data fetched simultaneously from diverse machines and supports the location and coordination of named data among peer nodes without additional knowledge of network topology. The dynamic stream aggregation scheme employed by the protocol solves the problem of network asymmetry that plagues residential broadband networks. In addition, the stateless nature of the protocol allows for fast fail-over and adaptation to departure of source nodes from the network, mitigating the reliability problems of end-user machines. We present and evaluate the algorithms employed by our protocol architecture and propose an economic model that can be used in real-world applications of peer-to-peer media distribution. With the combination of an adaptive collaborative protocol core and a reasonable economic model, we deliver an architecture that enables flexible and scalable real-time media distribution in a completely decentralized, serverless fashion.by Dimitrios Christos Vyzovitis.S.M

Enhancing HPC on Virtual Systems in Clouds through Optimizing Virtual Overlay Networks

Virtual Ethernet overlay provides a powerful model for realizing virtual distributed and parallel computing systems with strong isolation, portability, and recoverability properties. However, in extremely high throughput and low latency networks, such overlays can suffer from bandwidth and latency limitations, which is of particular concern in HPC environments. Through a careful and quantitative analysis, I iden- tify three core issues limiting performance: delayed and excessive virtual interrupt delivery into guests, copies between host and guest data buffers during encapsulation, and the semantic gap between virtual Ethernet features and underlying physical network features. I propose three novel optimizations in response: optimistic timer- free virtual interrupt injection, zero-copy cut-through data forwarding, and virtual TCP offload. These optimizations improve the latency and bandwidth of the overlay network on 10 Gbps Ethernet and InfiniBand interconnects, resulting in near-native performance for a wide range of microbenchmarks and MPI application benchmarks

A decentralized framework for cross administrative domain data sharing

Federation of messaging and storage platforms located in remote datacenters is an essential functionality to share data among geographically distributed platforms. When systems are administered by the same owner data replication reduces data access latency bringing data closer to applications and enables fault tolerance to face disaster recovery of an entire location. When storage platforms are administered by different owners data replication across different administrative domains is essential for enterprise application data integration. Contents and services managed by different software platforms need to be integrated to provide richer contents and services. Clients may need to share subsets of data in order to enable collaborative analysis and service integration. Platforms usually include proprietary federation functionalities and specific APIs to let external software and platforms access their internal data. These different techniques may not be applicable to all environments and networks due to security and technological restrictions. Moreover the federation of dispersed nodes under a decentralized administration scheme is still a research issue. This thesis is a contribution along this research direction as it introduces and describes a framework, called \u201cWideGroups\u201d, directed towards the creation and the management of an automatic federation and integration of widely dispersed platform nodes. It is based on groups to exchange messages among distributed applications located in different remote datacenters. Groups are created and managed using client side programmatic configuration without touching servers. WideGroups enables the extension of the software platform services to nodes belonging to different administrative domains in a wide area network environment. It lets different nodes form ad-hoc overlay networks on-the-fly depending on message destinations located in distinct administrative domains. It supports multiple dynamic overlay networks based on message groups, dynamic discovery of nodes and automatic setup of overlay networks among nodes with no server-side configuration. I designed and implemented platform connectors to integrate the framework as the federation module of Message Oriented Middleware and Key Value Store platforms, which are among the most widespread paradigms supporting data sharing in distributed systems

WEBGOP : collaborative Web services based on graph-oriented programming

2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A Continuous Overlay Path Probing Algorithm For Overlay Networks

Bandwidth is a key factor in network technologies and it has been of major importance throughout the history of packet networks. In fact, bandwidth estimation is very beneficial to optimize the performance of end-to-end transport in several overlay applications such as Content Distribution Networks (CDNs), Peer-to-Peer (P2P) file sharing, and dynamic overlay routing. The end-to-end available bandwidth determines the extra bandwidth that can be provided to overlay traffic. Knowledge about the available bandwidth of an overlay path enables dynamic rate adoption and better bandwidth utilization by content distribution schemes in overlay networks. However, the important issue is how to measure the available bandwidth on an end-to-end overlay path without prior knowledge about the physical network. Over the last two decades, researchers have been trying to create algorithms to measure end-to-end available bandwidth and other bandwidth-related metrics accurately, quickly, and without affecting the traffic of the path. Active measurement techniques performed by overlay nodes can provide bandwidth estimations of an end-to-end overlay path. This thesis describes a new algorithm called “COPPA,” which is an in-band path probing algorithm for measuring the end-to-end available bandwidth of an overlay path accurately and continuously. The aim is to provide up-to-date bandwidth information for enhanced content distribution processes in overlay networks. The primary idea is to perform active measurements using the applications’ packets instead of using extra probe packets. Such an in-band probing algorithm reduces measurement overhead on the selected overlay path. Several experiments were carried out using the OMNeT++ simulation framework. The designed algorithm was evaluated using experimental data. The obtained results show that the continuous in-band overlay path probing algorithm (COPPA) provides up-to-date bandwidth information with reduced overhead and minimal impact on the traffic of the path

ShallowForest: Optimizing All-to-All Data Transmission in WANs

All-to-all data transmission is a typical data transmission pattern in both consensus protocols and blockchain systems. Developing an optimization scheme that provides high throughput and low latency data transmission can significantly benefit the performance of those systems. This thesis investigates the problem of optimizing all-to-all data transmission in a wide area network (WAN) using overlay multicast. I first prove that in a congestion-free core network model, using shallow tree overlays with height up to two is sufficient for all-to-all data transmission to achieve the optimal throughput allowed by the available network resources. Based on this finding, I build ShallowForest, a data plane optimization for consensus protocols and blockchain systems. The goal of ShallowForest is to improve consensus protocols' resilience to skewed client load distribution. Experiments with skewed client load across replicas in the Amazon cloud demonstrate that ShallowForest can improve the commit throughput of the EPaxos consensus protocol by up to 100% with up to 60% reduction in commit latenc

Reducing Internet Latency : A Survey of Techniques and their Merit

Bob Briscoe, Anna Brunstrom, Andreas Petlund, David Hayes, David Ros, Ing-Jyh Tsang, Stein Gjessing, Gorry Fairhurst, Carsten Griwodz, Michael WelzlPeer reviewedPreprin