36 research outputs found
Managing a peer-to-peer backup system: does imposed fairness socially outperform a revenue-driven monopoly ?
International audienceWe study a peer-to-peer backup system, where users offer some of their storage space to provide service for the others. The economic model for such a system is different from the ones applicable to peer-to-peer file sharing systems, since the storage capacity is a private good here. We study two mechanisms aimed at incentivizing users to offer some of their capacity: a price-based scheme (here a revenue-driven monopoly) and a more classical symmetric scheme (imposing users to contribute to the service at least as much as use it). We compare the outcomes of such mechanisms to the socially optimal situation that could be attained if users were not selfish, and show that depending on user heterogeneity, a revenue maximizing monopoly can be a worse or a better (in terms of social welfare) way to manage the system than a symmetric scheme
Adaptive Redundancy Management for Durable P2P Backup
We design and analyze the performance of a redundancy management mechanism
for Peer-to-Peer backup applications. Armed with the realization that a backup
system has peculiar requirements -- namely, data is read over the network only
during restore processes caused by data loss -- redundancy management targets
data durability rather than attempting to make each piece of information
availabile at any time.
In our approach each peer determines, in an on-line manner, an amount of
redundancy sufficient to counter the effects of peer deaths, while preserving
acceptable data restore times. Our experiments, based on trace-driven
simulations, indicate that our mechanism can reduce the redundancy by a factor
between two and three with respect to redundancy policies aiming for data
availability. These results imply an according increase in storage capacity and
decrease in time to complete backups, at the expense of longer times required
to restore data. We believe this is a very reasonable price to pay, given the
nature of the application.
We complete our work with a discussion on practical issues, and their
solutions, related to which encoding technique is more suitable to support our
scheme
A Resource-Aware and Time-Critical IoT Framework
Internet of Things (IoT) systems produce great
amount of data, but usually have insufficient resources to
process them in the edge. Several time-critical IoT scenarios
have emerged and created a challenge of supporting low latency
applications. At the same time cloud computing became a success
in delivering computing as a service at affordable price with great
scalability and high reliability. We propose an intelligent resource
allocation system that optimally selects the important IoT data
streams to transfer to the cloud for processing. The optimization
runs on utility functions computed by predictor algorithms that
forecast future events with some probabilistic confidence based
on a dynamically recalculated data model. We investigate ways of
reducing specifically the upload bandwidth of IoT video streams
and propose techniques to compute the corresponding utility
functions. We built a prototype for a smart squash court and
simulated multiple courts to measure the efficiency of dynamic
allocation of network and cloud resources for event detection
during squash games. By continuously adapting to the observed
system state and maximizing the expected quality of detection
within the resource constraints our system can save up to 70%
of the resources compared to the naive solution
Policy Injection: a Cloud Dataplane DoS Attack
Enterprises continue to migrate their services to the cloud on a massive scale, but the increasing attack surface has become a natural target for malevolent actors. We show policy injection, a novel algorithmic complexity attack that enables a tenant to add specially tailored ACLs into the data center fabric to mount a denial-of-service attack through exploiting the built-in security mechanisms of the cloud management systems (CMS) . Our insight is that certain ACLs, when fed with special covert packets by an attacker, may be very difficult to evaluate, leading to an exhaustion of cloud resources. We show how a tenant can inject seemingly harmless ACLs into the cloud data plane to abuse an algorithmic deficiency in the most popular cloud hypervisor switch, Open vSwitch, and reduce its effective peak performance by 80-90%, and, in certain cases, denying network access altogether
Orchestration of Network Services Across Multiple Operators: The 5G Exchange Prototype
Future 5G networks will rely on the coordinated
allocation of compute, storage, and networking resources in
order to meet the functional requirements of 5G services as well
as guaranteeing efficient usage of the network infrastructure.
However, the 5G service provisioning paradigm will also require
a unified infrastructure service market that integrates multiple
operators and technologies. The 5G Exchange (5GEx) project,
building heavily on the Software-Defined Network (SDN) and the
Network Function Virtualization (NFV) functionalities, tries to
overcome this market and technology fragmentation by
designing, implementing, and testing a multi-domain
orchestrator (MdO) prototype for fast and automated Network
Service (NS) provisioning over multiple-technologies and
spanning across multiple operators. This paper presents a first
implementation of the 5GEx MdO prototype obtained by
extending existing open source software tools at the disposal of
the 5GEx partners. The main functions of the 5GEx MdO
prototype are showcased by demonstrating how it is possible to
create and deploy NSs in the context of a Slice as a Service
(SlaaS) use-case, based on a multi-operator scenario. The 5GEx
MdO prototype performance is experimentally evaluated
running validation tests within the 5GEx sandbox. The overall
time required for the NS deployment has been evaluated
considering NSs deployed across two operators
Analysis of end-to-end multi-domain management and orchestration frameworks for software defined infrastructures: an architectural survey
Over the last couple of years, industry operators' associations issued requirements towards an end-to-end management and orchestration plane for 5G networks. Consequently, standard organisations started their activities in this domain. This article provides an analysis and an architectural survey of these initiatives and of the main requirements, proposes descriptions for the key concepts of domain, resource and service slicing, end-to-end orchestration and a reference architecture for the end-to-end orchestration plane. Then, a set of currently available or under development domain orchestration frameworks are mapped to this reference architecture. These frameworks, meant to provide coordination and automated management of cloud and networking resources, network functions and services, fulfil multi-domain (i.e. multi-technology and multi-operator) orchestration requirements, thus enabling the realisation of an end-to-end orchestration plane. Finally, based on the analysis of existing single-domain and multi-domain orchestration components and requirements, this paper presents a functional architecture for the end-to-end management and orchestration plane, paving the way to its full realisation.This work was partially supported by the ICT14 5GExchange (5GEx) innovation project (grant agreement no.671636) co-funded by the European Union under the Horizon 2020 EU Framework Programme.Publicad