Service quality in P2P streaming systems

Relying on end users to contribute bandwidth to the system peer-to-peer (P2P) overlays provide a cheap and scalable way to distribute live video content in the Internet. However, being inherently dynamic due to peers joining and leaving the system at arbitrary time and running over the best-effort Internet, successful commercial usage of these systems may suffer from unstable media quality provided to end users. In this survey, we consider problems related to providing quality of media delivery in P2P streaming systems. We show that in spite of numerous systems available today no one incorporates mechanisms capable to maintain a certain level of quality of delivered media. We identify reasons behind that and discuss possible solutions to this problem.     

Video streaming distribution over mobile Internet: a survey

In recent times, mobile Internet has witnessed the explosive growth of video applications, embracing user-generated content, Internet Protocol television (IPTV), live streaming, video-on-demand, video conferencing, and FaceTime-like video communications. The exponential rise of video traffic and dynamic user behaviors have proved to be a major challenge to video resource sharing and delivery in the mobile environment. In this article, we present a survey of state-of-the-art video distribution solutions over the Internet. We first discuss the challenges of mobile peer-to-peer (MP2P)-based solutions and categorize them into two groups. We discuss the design idea, characteristics, and drawbacks of solutions in each group.We also give a reviewfor solutions of video transmission in wireless heterogeneous networks. Furthermore, we summarize the information-centric networking (ICN)-based video solutions in terms of in-network caching and name-based routing. Finally, we outline the open issues for mobile video systems that require further studies.     

Backscatter from the data plane – Threats to stability and security in information-centric network infrastructure

Information-centric networking (ICN) raises data objects to first class routable entities in the network and changes the Internet paradigm from host-centric connectivity to data-oriented delivery. However, current approaches to content routing heavily rely on data-driven protocol events and thereby introduce a strong coupling of the control to the data plane in the underlying routing infrastructure. In this paper, threats to the stability and security of the content distribution system are analyzed in theory, simulations, and practical experiments. We derive relations between state resources and the performance of routers, and demonstrate how this coupling can be misused in practice. We further show how state-based forwarding tends to degrade by decorrelating resources. We identify intrinsic attack vectors present in current content-centric routing, as well as possibilities and limitations to mitigate them. Our overall findings suggest that major architectural refinements are required prior to global ICN deployment in the real world.     

From content delivery today to information centric networking

Today, content delivery is a heterogeneous ecosystem composed by various independent infrastructures. The ever increasing growth of Internet traffic has encouraged the proliferation of different architectures to serve content provider needs and user demand. Despite the differences among the technology, their low level implementation can be characterized in a few fundamental building blocks: network storage, request routing, and data transfer. Existing solutions are inefficient because they try to build an information centric service model over a network infrastructure which was designed to support host-to-host communications. The Information-Centric Networking (ICN) paradigm has been proposed as a possible solution to this mismatch. ICN integrates content delivery as a native network feature. The rationale is to architect a network that automatically interprets, processes, and delivers content (information) independently of its location. This paper makes the following contributions: (1) it identifies a set of building blocks for content delivery, (2) it surveys the most popular approaches to realize the above building blocks, (3) it compares content delivery solutions relying on the current Internet infrastructure with novel ICN approaches.     

An architectural approach towards Future Media Internet

Internet is the most important information exchange means nowadays and has become the core communication environment, not only for business relations, but also for social and human interaction. Yet, the immense success of Internet has created even higher hopes and expectations for new immersive and real-time applications and services. However, there are no guarantees that the current Internet will be able to support them. To face the new requirements coming from these new applications and services, several architectural approaches have been proposed. Evolutionary and clean-slate approaches, based on content-centric architectures, have been proposed for meeting new requirements regarding media. This paper highlights the main architectural functions and presents a revolutionary protocol stack and a holistic architectural approach that targets Future Media Internet (FMI). Among the architectural functions and the holistic approach, the paper presents solutions to overcome the current content delivery limitations, moving intelligence in the network and converting it into a content oriented/centric network, that goes well beyond current CDNs; supporting the functionalities for producing, publishing, caching, finding and consuming content; and a novel Future Media Internet protocol stack and network architecture.     

A Survey of Application Layer Techniques for Adaptive Streaming of Multimedia

Though the integrated services model and resource reservation protocol (RSVP) provide support for quality of service, in the current Internet only best-effort traffic is widely supported. New high-speed technologies such as ATM (asynchronous transfer mode), gigabit Ethernet, fast Ethernet, and frame relay, have spurred higher user expectations. These technologies are expected to support real-time applications such as video-on-demand, Internet telephony, distance education and video-broadcasting. Towards this end, networking methods such as service classes and quality of service models are being developed. Today's Internet is a heterogeneous networking environment. In such an environment, resources available to multimedia applications vary. To adapt to the changes in network conditions, both networking techniques and application layer techniques have been proposed. In this paper, we focus on the application level techniques, including methods based on compression algorithm features, layered encoding, rate shaping, adaptive error control, and bandwidth smoothing. We also discuss operating system methods to support adaptive multimedia. Throughout the paper, we discuss how feedback from lower networking layers can be used by these application-level adaptation schemes to deliver the highest quality content.     

P2P multicast for pervasive ad hoc networks

During the last few years, the proliferation of miniaturised devices with networking capabilities has provided the technological grounds for pervasive networking environments. It is not visionary to foresee a world of pervasive devices embedded in the environment interacting between them, and with those carried by users, via wireless communications. In addition, fostered by the diffusion of small-size, computational-rich mobile devices, the way content is generated, and accessed is changing with respect to the legacy-Internet paradigm. An ever-increasing share of the Internet content is generated directly by the users, and shared on the network (following the User-Generated Content model). While today the legacy Internet is still used to share user-generated content, it is reasonable to envision that pervasive networking technologies will represent the natural platform to support this new model. This will result in content being distributed on users’ devices rather than on centralised servers on the Internet, and in users creating ad hoc networks to share content. The p2p paradigm is particularly suitable for this scenario, because communications will occur directly among users, instead of being necessarily mediated by centralised servers. Motivated by these remarks, in this work we focus on p2p multicast services over ad hoc networks aimed at sharing content among groups of users interested in the same topics. Specifically, starting from a reference solution in legacy wired networks (Scribe), we design a cross-layer optimised protocol (XScribe) that addresses most of the Scribe problems on ad hoc networks. XScribe exploits cross-layer interactions with a proactive routing protocol to manage group membership. Furthermore, it uses a lightweight, structureless approach to deliver data to group members. By jointly using experimental results and analytical models, we show that, with respect to Scribe, XScribe significantly reduces the packet loss and the delay experienced by multicast receivers, and increases the maximum throughput that can be delivered to multicast groups.     

Downloading trace study for BitTorrent P2P performance measurement and analysis

With the increasing client population and the explosive volume of Internet media content, the peer-to-peer networking technologies and systems provide a rapid and scalable content distribution mechanism in the global networks. The BitTorrent protocol and its derivatives are among the most popular peer-to-peer file sharing applications, which contribute a dominant fraction of today??s Internet traffic. In this paper, we conduct the performance measurement and analysis of BitTorrent systems with an extensive volume of real trace logs. We use several downloading-side metrics, including overall downloading time, maximum of downloading bandwidth, average bandwidth utilization, maximum of downloading connections, and average number of active connections, to derive various interesting results from the downloading-side aspect of network resource usage. Performance examination learns many new observations and characteristics into the virtue of BitTorrent protocols and systems, thereby providing beneficial information for bandwidth allocation and connection control in BitTorrent client applications. Therefore, this study is complementary to many previous research works that mainly focused on system-oriented and uploading-side performance measurements.     

Federation Lifecycle Management Incorporating Coordination of Bio-inspired Self-management Processes

As it has evolved, the Internet has had to support a broadening range of networking technologies, business models and user interaction modes. Researchers and industry practitioners have realised that this trend necessitates a fundamental rethinking of approaches to network and service management. This has spurred significant research efforts towards developing autonomic network management solutions incorporating distributed self-management processes inspired by biological systems. Whilst significant advances have been made, most solutions focus on management of single network domains and the optimisation of specific management or control processes therein. In this paper we argue that a networking infrastructure providing a myriad of loosely coupled services must inherently support federation of network domains and facilitate coordination of the operation of various management processes for mutual benefit. To this end, we outline a framework for federated management that facilitates the coordination of the behaviour of bio-inspired management processes. Using a case study relating to distribution of IPTV content, we describe how Federal Relationship Managers realising our layered model of management federations can communicate to manage service provision across multiple application/storage/network providers. We outline an illustrative example in which storage providers are dynamically added to a federation to accommodate demand spikes, with appropriate content being migrated to those providers servers under control of a bio-inspired replication process.     

基于P2P系统的DDoS攻击及其防御技术研究综述*

P2P软件系统已成为Internet上最流行和成功的网络应用之一,其协议和实现的可靠性与安全性必须得到充分的研究和论证。本文首先概述了利用P2P系统进行DDoS攻击的原理,并根据攻击方式的不同将现有研究划分为主动攻击和被动攻击两种。综述了当前针对基于P2P的DDoS攻击的防御方法,分别从基于验证的方法、基于成员管理的方法、基于信誉的方法和受害者端的方法四个方面进行说明。最后,本文从推动P2P网络安全和Internet网络安全的角度出发,对基于P2P的DDoS攻击及其防御技术未来的研究方向进行了探讨。     

SIP终端中拓扑感知的P2P中继查找机制实现①

由于Internet采用尽力而为的服务,VoIP系统存在QoS问题。为改善QoS,多数系统采用“应用层路由”方案,该方案关键是如何查找拓扑最优中继节点。结合P2P技术,提出一种拓扑感知的P2P中继查找机制。首先构建一个Cluster Overlay网络来模拟真实的Internet拓扑;在Cluster Overlay网络上设计一种拓扑感知的中继查找算法;最后在SIP终端中实现这种方案。在NS2平台上对Cluster Overlay网络和中继查找机制进行了仿真实验。结果表明：Cluster Overlay网络和真实的Internet拓扑相似度很高,中继查找算法能查找到最优中继结点,从而改进了路径质量。     

Content-centric framework for Internet of Things

The Internet of Things (IoT) concentrates on content dissemination and retrieval, so it is significant to achieve efficient content delivery. However, the Internet focuses on end-to-end communications, which might degrade the content retrieval performance in mobile environments. By contrast, the content-centric mechanism might be an ideal method for achieving efficient content delivery although it suffers from flooding and reverse-path disruptions. Therefore, we are motivated to exploit the content-centric mechanism to achieve IoT-based content delivery, and employ the address-centric anycast to overcome the limitations of the content-centric mechanism. Inspired by the idea, we propose a content-centric framework for IoT. The experimental results show that the proposed framework reduces the content communication cost and improves the content acquisition success rate.

     

Optimized P2P streaming for wireless distributed networks

The future Internet will support pervasive applications and communications models that require end-nodes cooperation, such as fog computing and machine-to-machine communications. Among the many applications, also video streaming can be provided with a cooperative and peer-to-peer approach. Cooperative distribution requires building a distribution overlay on top of the physical topology (the underlay). This work proposes an optimized, cross-layer approach to build this overlay minimizing the impact on the underlay. We design an optimal strategy, which is proven to be NP-complete, and thus not solvable with a distributed, lightweight protocol. The optimal strategy is relaxed exploiting the knowledge on the betweenness centrality of the nodes in the underlay topology, obtaining two easily implementable solutions applicable to any link-state protocol for distributed wireless mesh networks. The additional introduction of heuristic improvements further optimizes the performance in real network scenarios. Extensive simulation results support the theoretical findings using three different network topologies. They show that the relaxed implementations are reasonably close to the optimal solution, and provide vast gains compared to the traditional overlay topologies that peer-to-peer applications build.     

ORN: A content-based approach to improving supplier discovery in P2P VOD networks

There are two major building blocks in operating a peer-to-peer (P2P) video-on-demand (VOD) network: supplier discovery and content delivery. Supplier discovery concerns the discovery of peer nodes in the network that can provide the streaming data blocks needed for playing by a local node. The more suppliers one can discover, the higher the chance of locating quality suppliers for delivering contents smoothly to ensure uninterrupted playback. The key to supplier discovery is to establish and track the supply-demand relationship among the peers. For P2P VOD, the supply-demand relationship is determined by the buffer contents of the peers. Unfortunately, the buffer contents change rapidly as peers play the video, especially under VCR operations. The challenge is to track all the dynamic relationships in an efficient way. In this paper, we propose an Overlapping Relation Network (ORN). The idea is to track the dynamic supply-demand relationship by tracking the overlapping of peers’ buffer contents. As long as peers play the video at the same rate, the overlapping relationship is stable and can be used for low-cost supplier discovery. Extensive analyses and simulation experiments show that in most cases the ORN can discover more than 96% of the suppliers in the network, resulting in a streaming continuity that is superior to that of other approaches.     

HEURISTIC ALGORITHMS FOR SURVIVABLE P2P MULTICASTING

The growing volume of Internet traffic, increasing popularity of streaming services, and limited scalability of existing network techniques trigger the need to develop new delivery solutions based on a multicasting approach. Multicasting—defined as a one-to-many delivery technique—enables effective distribution of many kinds of content to end users. In this article we focus on peer-to-peer (P2P) multicasting, which combines concepts of P2P systems and multicasting solutions; in other words, the multicast tree is constructed using end hosts (peers). Because P2P multicasting can be applied to deliver content with high reliability requirements, we introduce to P2P multicasting additional survivability constraints that guarantee delivery of content in the case of network failures. We formulate a mixed-integer programming (MIP) optimization problem of survivable P2P multicasting. Because the problem is nondeterministic polynomial time (NP)-hard and exact methods such as branch-and-cut can be applied for only a relatively small problem instance, we propose two heuristic algorithms based on evolutionary approach and Tabu Search methods. Extensive computational experiments show that both heuristic algorithms provide results close to optimal—the average gap to optimal results is 0.26% and 5.15% in the case of evolutionary and Tabu Search methods, respectively.     

Detection and mitigation of localized attacks in a widely deployed P2P network

Several large scale P2P networks operating on the Internet are based on a Distributed Hash Table. These networks offer valuable services, but they all suffer from a critical issue allowing malicious nodes to be inserted in specific places on the DHT for undesirable purposes (monitoring, distributed denial of service, pollution, etc.). While several attacks and attack scenarios have been documented, few studies have measured the actual deployment of such attacks and none of the documented countermeasures have been tested for compatibility with an already deployed network. In this article, we focus on the KAD network. Based on large scale monitoring campaigns, we show that the world-wide deployed KAD network suffers large number of suspicious insertions around shared contents and we quantify them. To cope with these peers, we propose a new efficient protection algorithm based on analyzing the distribution of the peers’ ID found around an entry after a DHT lookup. We evaluate our solution and show that it detects the most efficient configurations of inserted peers with a very small false-negative rate, and that the countermeasures successfully filter almost all the suspicious peers. We demonstrate the direct applicability of our approach by implementing and testing our solution in real P2P networks.     

The role of communication systems in smart grids: Architectures,technical solutions and research challenges

The purpose of this survey is to present a critical overview of smart grid concepts, with a special focus on the role that communication, networking and middleware technologies will have in the transformation of existing electric power systems into smart grids. First of all we elaborate on the key technological, economical and societal drivers for the development of smart grids. By adopting a data-centric perspective we present a conceptual model of communication systems for smart grids, and we identify functional components, technologies, network topologies and communication services that are needed to support smart grid communications. Then, we introduce the fundamental research challenges in this field including communication reliability and timeliness, QoS support, data management services, and autonomic behaviors. Finally, we discuss the main solutions proposed in the literature for each of them, and we identify possible future research directions.     

信息中心网络中缓存技术研究综述

因特网中日益增长的内容获取需求促使学术界提出了多种以信息为中心的未来网络架构。这类架构将以主机为中心的通信模式转变为以内容为中心。信息中心网络（ICN）最重要的特征之一是利用内置缓存减少用户获取内容的时延、节省网络带宽和缓解网络拥塞。与传统的内容分发网络（CDN）、对等网络（P2P）和Web缓存系统相比,ICN缓存系统呈现出一系列的新特征。分析了缓存新特征对ICN研究带来的挑战;从多方面重点阐述了ICN缓存的优化方法,详细分析对比了不同缓存策略;指出了未来研究方向并总结全文。     

Design and implementation of the OFELIA FP7 facility: The European OpenFlow testbed

The growth of the Internet in terms of number of devices, the number of networks associated to each device and the mobility of devices and users makes the operation and management of the Internet network infrastructure a very complex challenge. In order to address this challenge, innovative solutions and ideas must be tested and evaluated in real network environments and not only based on simulations or laboratory setups.OFELIA is an European FP7 project and its main objective is to address the aforementioned challenge by building and operating a multi-layer, multi-technology and geographically distributed Future Internet testbed facility, where the network itself is precisely controlled and programmed by the experimenter using the emerging OpenFlow technology. This paper reports on the work done during the first half of the project, the lessons learned as well as the key advantages of the OFELIA facility for developing and testing new networking ideas.An overview on the challenges that have been faced on the design and implementation of the testbed facility is described, including the OFELIA Control Framework testbed management software. In addition, early operational experience of the facility since it was opened to the general public, providing five different testbeds or islands, is described.     

基于信任介绍的P2P安全研究

本文在分析研究传统信任模型的基础上,结合近两年最热门的网络架构方式,建立了一种新的基于P2P网络的信任介绍机制.这个机制利用了节点过去在网络中的历史经验,建立了节点之间的信任关系,更加有效的去解决网络中信任关系,而其算法比较简洁,比一些具有复杂算法的信任模型更适合在现实网络中的应用.该机制能够增强网络可用性,具有结构简单、可靠性强的优点.