Pure P2P Research Articles

Software‐defined content delivery network at the edge for adaptive video streaming

SummaryIn DASH (Dynamic Adaptive Streaming over HTTP), it is required to store multiple encoding for same video segments which increases the storage requirement of CDN (content delivery network) servers. Further, to keep network delay in check, it is not feasible to continuously increase the number of CDN servers in different geographical locations as per the ever‐increasing demand. Peer‐to‐peer (P2P) CDN acts as an elegant alternative to supplement existing CDN servers to harness the benefits of both P2P and CDN technologies. We present the concept of “CDN at the edge,” where end hosts can collaborate for video streaming in pure P2P manner to provide better QoE (Quality of Experience). However, dynamically changing behavior of underlying network, uncertain leaving, joining pattern of clients, and frequent change in source node during video streaming session make the selection of the desired bitrate (at any given time) extremely difficult. In this paper, we have designed and implemented a software‐defined network (SDN)‐based P2P CDN system that supports browser‐based adaptive video streaming. SDN provides global view of the topology and thus assists in providing timely information about leaving or joining peers in the proposed “CDN at the edge.” Further, this SDN‐based P2P CDN is compared with non‐SDN‐based P2P CDN using both virtual switch‐based emulations and physical switch‐based actual implementation. The comparison is performed under different churn rates with respect to QoE parameters such as start‐up delay, bitrate, stall count, and its duration. The experimental results prove the applicability of our approach.

Resource discovery mechanisms in pure unstructured peer-to-peer systems: a comprehensive survey

The concept of unstructured Peer-to-Peer (P2P) systems—setting free from any structural constraints—has put forward an appropriate paradigm for sharing a wide assortment of resources in a distributed-sharing manner efficiently. More importantly, unstructured P2P systems’ architecture and concepts have permeated diverse spheres of today’s successful and world-famous computer science areas, including NoSQL databases for excellently sharing data. However, pinpointing any given appropriate resource in such massive systems, namely unstructured P2P systems, is a challenging task; the two of the most dispensable rationales behind this proclaim are large scales of such systems and unstructured nature of overlay networks. Finding a decent resource with low response time, low bandwidth consumption, and high success-rate has played a crucial role in both the overall system performance and the functionality of P2P systems. Briefly, an efficacious resource discovery mechanism is the lifeblood of any productive P2P system. Given these points, in this study, we present an exhaustive survey on state-of-the-art resource discovery mechanisms employed in file-sharing pure unstructured P2P systems; we offer a new resource discovery categorization accordingly. Furthermore, we deeply delve into a plethora of resource searching methods and their merits as well as demerits to furnish the paper with an in-depth evaluation.

Implementation of hybrid P2P networking distributed web crawler using AWS for smart work news big data

Web crawlers collect and index the vast amount of data available online to gather specific types of objective data such as news that researchers or practitioners need. As big data are increasingly used in a variety of fields and web data are exponentially growing each year, the importance of web crawlers is growing as well. Web servers that currently handle high traffic, such as portal news servers, have safeguards against security threats such as distributed denial-of-service (DDoS) attacks. In particular, the crawler, which causes a large amount of traffic to the Web server, has a very similar nature to DDoS attacks, so the crawler’s activities tend to be blocked from the web server. A peer-to-peer (P2P) crawler can be used to solve these problems. However, the limitations with the pure P2P crawler is that it is difficult to maintain the entire system when network traffic increases or errors occur. Therefore, in order to overcome these limitations, we would like to propose a hybrid P2P crawler that can collect web data using the cloud service platform provided by Amazon Web Services (AWS). The hybrid P2P networking distributed web crawler using AWS (HP2PNC-AWS) is applied to collecting news on Korea’s current smart work lifestyle from three portal sites. In Portal A where the target server does not block crawling, the HP2PNC-AWS is faster than the general web crawler (GWC) and slightly slower than the server/client distributed web crawler (SC-DWC), but it has a similar performance to the SC-DWC. However, in both Portal B and C where the target server blocks crawling, the HP2PNC-AWS performs better than other methods, with the collection rate and the number of data collected at the same time. It was also confirmed that the hybrid P2P networking system could work efficiently in web crawler architectures.

Peer-to-Peer Control System for DC Microgrids

We propose and implement a dc microgrid with a fully decentralized control system, using the ICT concept of network overlays and peer-to-peer (P2P) networks. Decentralization not only concerns the physical systems and control logic but also the control structure which provides the network infrastructure on which energy management is carried out. In this paper, we show how such decentralization can be achieved using P2P frameworks as underlying control structures and implemented a pure P2P to eliminate single points of failure. For this, a direct current open energy system made of the interconnection of standalone dc nanogrids is used as underlying microgrid. The power flows between nanogrids are controlled by a decentralized exchange strategy: each household can request or respond to energy deals with its neighbors without requiring system-wide knowledge or control. Using dc combined with a layered, modular software allows loose coupling which increases flexibility and dependability. The system has been implemented and tested on a full-scale platform in Okinawa including 19 inhabited houses. Real data analysis as well as simulations demonstrate improvements in self-sufficiency compared to other types of systems. Resilience against utility blackouts is proven in practice.

A Sustainable Home Energy Prosumer-Chain Methodology with Energy Tags over the Blockchain

In this paper, we aim to provide a power trade system that will promote a sustainable electrical energy transaction ecosystem between prosumers and consumers of smart homes. We suggest a blockchain-based peer-to-peer (P2P) energy transaction platform be implemented to enable efficient electrical energy transaction between prosumers. We suggest the platform be built on the blockchain, as this technology allows a decentralized and distributed trading system, and allows a more transparent, trustworthy and secure P2P trading environment. We believe that such characteristics of the blockchain are necessary in electrical energy transactions within the smart home environment because the smart home aims to enhance user comfort and security, along with energy conservation and cost-savings. First, we classify the two different types of P2P trade to identify which will best benefit from the use of the suggested blockchain-based P2P energy-transaction platform. Within the two types of P2P trade, that we classify (pure P2P trade and hybrid P2P trade), the hybrid P2P trade will benefit more from a blockchain-based P2P energy-transaction platform. In the blockchain-based P2P energy-transaction platform, a smart contract is embedded in the blockchain and called an energy tag. The energy tag will set conditions for making every future energy transaction more cost-efficient while maintaining the most ideal and high-quality energy selection. With the blockchain-based energy tag in the energy-transaction process, multiple energy resources and home appliances will be democratically connected in order to provide users with high-quality, low-cost energy at all times and locations. In this paper, we provide simulation results that compare the unit price of electrical energy on the suggested platform to the unit price of electrical energy set by currently existing conventional power-generation companies. Additionally, we present simulation results that calculate how long initial investments to create a smart home environment that enables P2P energy transactions will take to be paid back. Based on simulation results, we believe that, in the long run, the suggested blockchain-based P2P energy-transaction platform will create a sustainable energy-transaction environment between consumers and prosumers, and the expanding ecosystem will enable the development of a trusted, sustainable, secure and energy-efficient energy transaction environment.

SureTrust: a super peer-aware trust model for 2-level P2P networks

With the growth of P2P applications, more and more trust models have been proposed for curbing malicious behavior, most of which are suitable for pure P2P networks, including the structured P2P networks and the unstructured P2P networks. This paper presents a super peer-aware trust model, sureTrust, for 2-level P2P networks. The super peer of a subnet is responsible for calculating the peers’ trust in its subnet, and the super peer’s trust is correlated with the trust of the peers in its subnet. To discourage peers from behaving maliciously, we allow a peer to establish transactions only with the peers whose trust is similar to that of the peer. Also, a super peer could separate the connections of a peer in its subnet to the outside subnets as the punishment on the peer’s behavior. The simulation results show that the sureTrust model could improve normal peers’ successful download rate and resist different types of attacks.

A Super-Peer Coordination Scheme for Decentralized Peer-to-Peer Networking Using Mobile Agents

Peer-to-Peer(P2P) systems are generally classified into two categories; hybrid and pure P2P. Hybrid systems have a single central index server keeping the details of shared information, so that undesirable effects such as heavy load on that server and lack of fault-tolerance can be caused. Pure P2P causes the other problems such as message flooding and scalability although it shows high degree of fault-tolerance. Recently, mobile agent-based distributed computing has been receiving wide attention for its potential to support disconnected operations, high asynchrony, and thus saving network bandwidth. In this paper, a new scheme of peer coordination is proposed for a decentralized P2P network with self-organizing structure. We deployed mobile agents for incorporating the advantages of usage of mobile agents into our P2P network. Proposed P2P network has both advantages of hybrid and pure P2P. The problems of heavy load on the server and lack of fault-tolerance are improved by using multiple special peers called super-peers. And the problems of pure P2P can be reduced by using mobile agents.

Distributed hybrid P2P networking systems

Welcome to the special issue of Peer-to-Peer Networking and Applications. This issue contains a collection of the best papers out of various authors who have been submitted to this special issue. Most multimedia-based content service environments are embedded in a large-capacity server and adopt the client–server model. In such a model, excessive load on the server can slow down or break the network. This problem can be solved by applying a peer-to-peer (P2P) network in a distributed environment for smoother sharing and distribution of resources. Depending on the existence of an index server, the P2P models are categorized as hybrid peer-to-peer and pure peer-to-peer networks. A hybrid P2P network is one that has an index server containing information on the locations of resources at the center, and which uses the index server for search. A pure P2P network is one that directly executes the search process among hosts without a server between the hosts [9–11]. The main goal of this issue is to bring together researchers and practitioners in areas of media streaming, multicasting and multimedia delivery, P2P file sharing to share their visions, research achievements and solutions, to resolve the challenge issues and to establish worldwide cooperative researches and developments. This will give an opportunity to push further the discussion upon the potential distributed hybrid networking systems acrossmany communities. Some of these research areas are listed below.

Enabling P2P One-View Multiparty Video Conferencing

Multiparty video conferencing (MPVC) facilitates real-time group interaction between users. While P2P is a natural delivery solution for MPVC, a peer often does not have enough bandwidth to deliver her video to all other peers in the conference. Recently, we have witnessed the popularity of one-view MPVC, where each user only watches full video of another user. One-view MPVC opens up the design space for P2P delivery. In this paper, we explore the feasibility of a pure P2P solution for one-view MPVC. We characterize the video source rate region achievable through video relays between peers. For both homogeneous and heterogeneous MPVC systems, we establish tight universal video rate lower bounds that are independent of the number of peers, the number of video sources, and the specific viewing relations between peers. We further propose, P2P video relay designs to approach the maximal video rate region. Through numerical simulations, we verified that the derived lower bounds are indeed tight bounds, and the proposed bandwidth allocation algorithm can achieve a close-to-optimal peer upload bandwidth utilization. Our results demonstrate that P2P is a promising solution for one-view MPVC. Insights obtained from our study can be used to guide the design of P2P MPVC systems.

On the performance of ACO-based methods in p2p resource discovery

Over the recent years peer-to-peer (p2p) systems have become increasingly popular. As of today most of the internet IP traffic is already transmitted in this format and still it is said to double in volume till 2014. Most p2p systems, however, are not pure serverless solutions, nor is the searching in those networks highly efficient, usually achieved by simple flooding. In order to confront with the growing traffic we must consider more elaborate search mechanisms and far less centralized environments. An effective proposal to this problem is to solve it in the domain of ant colony optimization metaheuristics. In this paper we present an overview of ACO algorithms that offer the best potential in this field, under the strict requirements and limitations of a pure p2p network. We design several experiments to serve as an evaluation platform for the mentioned algorithms to conclude the features of a high quality approach. Finally, we consider two hybrid extensions to the classical algorithms, in order to examine their contribution to the overall quality robustness.

Optimal Content Placement for Peer-to-Peer Video-on-Demand Systems

In this paper, we address the problem of content placement in peer-to-peer (P2P) systems, with the objective of maximizing the utilization of peers' uplink bandwidth resources. We consider system performance under a many-user asymptotic. We distinguish two scenarios, namely Distributed Server Networks (DSNs) for which requests are exogenous to the system, and Pure P2P Networks (PP2PNs) for which requests emanate from the peers themselves. For both scenarios, we consider a loss network model of performance and determine asymptotically optimal content placement strategies in the case of a limited content catalog. We then turn to an alternative large scaling where the catalog size scales with the peer population. Under this scaling, we establish that storage space per peer must necessarily grow unboundedly if bandwidth utilization is to be maximized. Relating the system performance to properties of a specific random graph model, we then identify a content placement strategy and a request acceptance policy that jointly maximize bandwidth utilization, provided storage space per peer grows unboundedly, although arbitrarily slowly, with system size.

A pure peer-to-peer approach for kNN query processing in mobile ad hoc networks

Together with advanced positioning and mobile technologies, P2P query processing has attracted a growing interest number of location-aware applications such as answering kNN queries in mobile ad hoc networks. It not only overcomes drawbacks of centralized systems, for example single point of failure and bottleneck issues, but more importantly harnesses power of peers' collaboration. In this research, we propose a pure mobile P2P query processing scheme which primarily focuses on the search and validation algorithm for kNN queries. The proposed scheme is designed for pure mobile P2P environments with the absence of the base station support. Compared with centralized and hybrid systems, our system can reduce energy consumption more than six times by making use of data sharing from peers in a reasonable mean latency of processing time for networks with high density of moving objects as can be seen in the simulation results.

MashCache: Taming Flash Crowds by Using Their Good Features

This paper presents MashCache, a scalable client-side architecture for taming harsh effects of flash crowds. Like previous systems, MashCache extensively makes use of client resources to cache and share frequently accessed contents. To design MashCache, we carefully investigated the quantitative analysis of flash crowds in the wild and found out that flash crowds have three good features that can be used to simplify the overall design of MashCache. First, flash crowds start up very slowly. MashCache has enough time to prepare for the coming flash crowds. Second, flash crowds last for a short period. Since the accessed content is rarely updated in this short period, MashCache can employ a simple mechanism for cache consistency. Finally, the clients issue the same requests on the target web sites. This feature simplifies the cache management of MashCache because the cache explosion can be avoided. By using these good features of flash crowds, MashCache advances the state-of-the-art of P2P based caching systems for flash crowds; MashCache is a pure P2P system that combines 1) aggressive caching, 2) query-origin key, 3) two-phase delta consistency, and 4) carefully designed cache meta data. MashCache has another advantage. Since it works completely on client-side, MashCache can tolerate flash crowds even if the external services the mashup depends on are not equipped with flash-crowd-resistant mechanisms. In the experiments with up to 2,500 emulated clients, a prototype of MashCache reduces the number of requests to the original web servers by 98.2% with moderate overheads.

Efficient Content Replication Strategy for Data Sharing Considering Storage Capacity Restriction in Hybrid Peer-to-Peer Networks

Various kinds of content replication strategies in pure P2P networks have recently been examined. However, such strategies have not been thoroughly considered in hybrid P2P networks. In a hybrid P2P network, the target content can easily be found because there is a server that controls each peer and its content. Therefore, it is important to decrease futile storage resource consumption, since the data search cost through the network is relatively small. This paper proposes an effective content replication strategy that takes into account storage capacity restrictions. In brief, this method restricts the number of contents replicas possessed by a peer using threshold-based control by relocating or deleting excess replicas. Furthermore, the effectiveness of the proposal is evaluated using computer simulations.

An experimental study of peer behavior in a pure P2P network

Abstract Dynamic peer behavior in P2P networks has a large impact on the performance of the network because each peer acts simultaneously as a server and a client in an overlay network. However, peer behavior in pure P2P networks is not well known because there is no management system and the network size is large. We have proposed a measurement method to collect information efficiently, and a method of analyzing the peer behavior with or without file uploading for pure P2P file sharing networks. These methods have been applied to Winny, which is the most popular P2P file sharing application in Japan. The analysis results show that the network is composed of about 30% of peers observed in 24 h, and 50% of peers contribute to the network as file uploaders. Selfish peers, which leave the network after downloading, are observed especially in the morning. The file uploading peers and the peers joining after midnight remain in the network for a long period. We also give mathematical fitting for the distribution of the peer lifetime and the frequency of joining the network. These results show that the distribution of lifetime does not have a heavy tail, and the behavior of peers joining the network is not a Poisson process.

A Containment-Based Security Model for Cycle-Stealing P2P Applications

ABSTRACT P2P networks and the computations they enable hold great potential in creating the next generation of large-scale distributed applications. However, the P2P phenomenon has largely left untouched large organizations and businesses that have stringent security requirements and are uncomfortable with the anonymity and lack of centralized control/censorship which are the features of P2P systems. Hence, there is an urgent need to address the security concerns in deploying P2P systems which can leverage the underutilized compute resources in organizations across the world. This article proposes a containment-based security model (CBSM) for cycle-stealing P2P applications, based on the Secure Linux (SE Linux) Operating System, which alleviates existing security concerns, allowing peers to host untrusted or even hostile applications. Our approach is suitable for pure P2P applications and requires no message exchanges or trust computations in ensuring security. Testing via deployment of potentially malicious remote code proves the effectiveness of the proposed system.

Designing an effective P2P system for a VoD system to exploit the multicast communication

A distributed video-on-demand system (DVoD) with multiple server-nodes is a cost-effective and fault-tolerant solution for a high scalable enterprise video-on-demand (VoD) system. However, such a server-oriented design is highly vulnerable to workload variations given that the service capacity is limited. Peer-to-Peer (P2P) has been introduced as an architectural solution with self-growing capacity. However, the characteristics of a pure P2P system such as the peer transient nature and high network overhead make this kind of architecture unsuitable for a fully interactive VoD system. In this paper, we propose a new efficient integrated VoD architecture, called D P n 2 P m , that combines DVoD with a P2P system and multicast communications. The DVoD’s server-nodes provide a minimum required quality of service (QoS) and the P2P system is able to offer the mechanism to increase the system service capacity according to client demands. Multicast communication, wherever it is possible, is effectively exploited by our P2P system. In our design, each client is able to send video information to a set of m clients using only one multicast channel. Furthermore, the collaboration mechanism is able to coordinate a set of clients to create one collaboration group to replace the server, providing an extensive, efficient and low network-overhead collaboration mechanism from n -peers to m -peers. Regardless of the video the client is watching, our P2P scheme allows every active client to collaborate with the server. The P2P scheme is complemented with recovery mechanisms that are able to replace the failed client before affecting the QoS, offering continuous playback. The proposed approach has been broadly evaluated, firstly using a mathematical model to derive the theoretical performance and secondly using a simulation environment to analyze the system’s dynamic behavior, the VCR interaction impact and the client failures. Comparing D P n 2 P m with other DVoD architectures and the most relevant P2P delivery policies, we show that our design is an improvement on previous solutions, providing a higher scalability.

A pure P2P synchronous collaborative system

This paper presents design and implementation of a collaborative system, called Decentralised Synchronous Collaboration (DSC), based on a pure P2P architecture without using any server at all. It relies on group agents located on peers' computers to coordinate group as well as peer management, and provides a message handler to deal with the correct message passing directly among group peers. DSC is implemented using JXTA technology that includes virtual JXTA networks, a set of standard protocols and basic services to let peers finding each other, forming groups, and exchanging messages across firewalls and Network Address Translators (NATs).

A Strategy for Efficient Update Propagation on Peer-to-Peer Based Content Distribution Networks

As demand for high fidelity multimedia content has soared, content distribution has emerged as a critical application. Large multimedia files require effective content distribution services such as content distribution networks (CDNs). A recent trend in CDN development is the use of peer-to-peer (P2P) techniques. P2P-based CDNs have several advantages over conventional non-P2P-based CDNs in scalability, fault resilience, and cost-effectiveness. Unfortunately, P2P-based content distribution poses a crucial problem in that update propagation is quite difficult to accomplish. This is because peers cannot obtain a global view of replica locations on the network. There are still several issues in conventional approaches to update propagation. They degrade the scalability, the fault resilience, and the cost-effectiveness of P2P-based content distribution, they also consume the network bandwidth, or take a long time. In this paper, we propose the speculative update, which quickly propagates an update to replicas with less bandwidth consumption in a pure P2P fashion. The speculative update enables a fast update propagation on structured P2P-based CDNs. Each server attempts to determine the directions in which there will be replicas with a high probability and speculatively relays update messages in those directions. Simulation results demonstrate that our mechanism quickly propagates an update to replicas with less bandwidth consumption. The The speculative update completes update propagation as fast as the simple gossip-based update propagation even with up to 69% fewer messages per second. Compared to the convergence-guaranteed random walk, the speculative update completes an update propagation faster by up to 92%.

Efficient Routing in Multi-ring Content Addressable Network

RCAN [1] is a novel multi-ring content addressable peer-to-peer system. RCAN was proposed in the aim of improving the routing performance of CAN [4] overlays while minimizing the maintenance overhead during nodes churn in large networks. The key idea of RCAN is to equip each node with few long-links towards some distant nodes. Long-links are clockwise directed and wrap around to form small rings along each dimension. The number of rings and their sizes self-adjust as nodes join and leave the systems. RCAN is a pure P2P design, where all nodes assume the same responsibility. Unlike some existing P2P overlays, RCAN is self-organizing and does not assume any a-priori fixed limits for the network size or the routing state per node. Each node auto-adapts its routing state to cope with network changes. We present in this paper an extensive study of the routing performance of RCAN under uniform and non-uniform data distributions. Experimental results show that in an overlay of n nodes, a node maintains a routing state of O(log n) long-links in average, and is able to reach any other nodes within O(log n) routing hops even in the presence of non-uniform space partitioning. Using simulation we demonstrate the full scalability and efficiency of our design and its advantages over other existing methods.