Peer Heterogeneity Research Articles

Applying multiple description coding to enhance the streaming scalability on CDN‐P2P network

AbstractOwing to the wide deployment of broadband networks, information can now be rapidly disseminated all over the world. Only the content of static texts and pictures has not yet met users' demands. Along with the rapid advance of computer‐related technologies, how to efficiently provide multimedia content for a large number of heterogeneous users on the Internet, especially videos, has become a noticeable issue. In this paper, we discuss the adaptation of multiple description coding (MDC) for the loopback buffering mechanism to address the issue of peer heterogeneity on content distribution network–peer to peer (CDN‐P2P) video‐on‐demand systems. Three description selection policies, Ordered, Round‐Robin, and Open‐Loop‐First (OLF), are studied. In addition, we propose the intra‐description recovery and inter‐description recovery to deal with failed peers. The simulation results show that the OLF with loopback‐MDC can significantly reduce the amount of uploading bandwidth of a proxy on CDN‐P2P video‐on‐demand systems, and the inter‐description recovery, sewing, can further effectively recover missing blocks and restore the continuity of a breaking sharing loop among peers. Copyright © 2009 John Wiley & Sons, Ltd.

AHLSS: A Hierarchical, Adaptive, Extendable P2P Live Streaming System

With the development of P2P streaming technology, various live streaming systems have been designed. Some measurement studies recently have shown that the most important issue exposed by previous systems is how to balance the benefits between the internet service provider, the internet content provider, and P2P users. This issue is induced by little consideration on management and control. Other problems include how to resolve peers churn and make full use of network bandwidth and apply incentive mechanism among peers. In this work we introduce AHLSS, a P2P system for live streaming which is hierarchical, adaptive, and extendable. We present the architecture of AHLSS which is divided into three layers. The top layer named AP (Administrator Peer) overlay consisted of some authentic servers, which are arranged by ICP (Internet Content Provider) to provide enrollment and authentication for peers to join P2P overlay and start to watch a media channel. Every AP locates in an alliance alone. The middle layer is SP overlay. AHLSS divides peers that participate in data transmission into two classes, including SP and NP, which base on the capability of peers. SP is elected by AP. SP has responsibility to route media packets quickly and reply peers' channel request within the cluster. The under layer consists of many clusters. A cluster is formed by uniting peers which have poor capability and little stability near SP. SP is named cluster-head with the responsibility for management of members in the cluster. Our system's innovative features are the following: It provides the function of enrollment and authentication; AP look up peer's EnrollInfo (a list, which keeps the register information of peers) periodically and apply a decision-tree approach to elect SP. It resolves problems which are associated with the dynamics and heterogeneity of peers; to cope with the problem of topology-mismatch, we design Alliance and Cluster to partition the physical location of peers and make use of the Two-hop Detection Algorithm which belongs to LTM technology to optimize the connection of SP among alliances; different transmission modes are designed on SP overlay and within cluster. Native mesh-pull is adopted in SP overlay and the hybrid mode includes tree-push and mesh-pull which are applied in NP (Normal Peer) overlay. It reduces the delay in chunks transmitted through SP to NP and makes full use of the upload bandwidth of peers; Approach of K degree redundancy cluster-head is adopted by NP, it is used to avoid the inorganized status for NPs which resulted from SP's failure. In this paper, we describe in detail the main algorithms that stand behind the design of AHLSS and present the analysis of architecture for various aspects including adaptability, scalability, efficiency, and robustness.

UP2P: a peer-to-peer overlay architecture for ubiquitous communications and networking

Approaches to building an intelligent consumer-friendly network have evolved over time from centralized switch-based to router- and server-based Internet architectures. We propose to drive this evolution further with a new highly scalable architecture that provides features to users derived from the computational and networking capabilities of very large populations of sophisticated terminals. This architecture relies on emerging peer-to-peer overlay technology. We describe a peer-to-peer overlay design that addresses requirements crucial for consumer applications, including overlay federation, peer heterogeneity, peer mobility, and service discovery. In addition, we introduce the concept of an overlay operator and describe the requirements for managed overlays. We have designed and implemented both a middleware and a peer-topeer platform that illustrates these concepts.

TTEM: An Effective Trust-Based Topology Evolution Mechanism for P2P Networks

Current unstructured peer-to-peer (P2P) systems lack fair topology structures, and take no consideration for malicious behaviors of peers. The main reason is that the topology is not sensitive to peer’s trust, and cannot accommodate heterogeneity of peers over the network. Thus, a feedback credibility based global trust model is presented in this paper. Then, based on the trust model, an adaptive topology evolution mechanism for unstructured P2P networks is proposed. Through this mechanism, trusted peers can migrate to the centric position, while untrusted peers to the edge of the topology, guaranteeing fairness during topology evolution. On the other hand, the mechanism can effectively counter the malicious behaviors of peers, and also has the incentive functionality, which incents peers to provide more high-quality services in order to get more return on services. Analysis and simulations show that, compared with the current topologies, the resulting topology mechanism demonstrates more effectiveness and robustness in combating the selfish or malicious behaviors of peers.

A performance evaluation of scalable live video streaming with nano data centers

To improve the efficiency and the quality of a service, a network operator may consider deploying a peer-to-peer architecture among controlled peers, also called here nano data centers , which contrast with the churn and resource heterogeneity of peers in uncontrolled environments. In this paper, we consider a prevalent peer-to-peer application: live video streaming. We demonstrate how nano data centers can take advantage of the self-scaling property of a peer-to-peer architecture, while significantly improving the quality of a live video streaming service, allowing smaller delays and fast channel switching. We introduce the branching architecture for nano datacenters (BAND), where a user can “pull” content from a channel of interest, or content could be “pushed” to it for relaying to other interested users. We prove that there exists an optimal trade-off point between minimizing the number of push, or the number of relaying nodes, and maintaining a robust topology as the number of channels and users get large, which allows scalability. We analyze the performance of content dissemination as users switch between channels, creating migration of nodes in the tree, while flow control insures continuity of data transmission. We prove that this p2p architecture guarantees a throughput independently of the size of the group. Analysis and evaluation of the model demonstrate that pushing content to a small number of relay nodes can have significant performance gains in throughput, start-up time, playback lags and channel switching delays .

Principles and performance analysis of SeCond: A system for epidemic peer-to-peer content distribution

We propose and design a peer-to-peer system, SeCond, addressing the distribution of large sized content to a large number of end systems in an efficient manner. In contrast to prior work, it employs a self-organizing epidemic dissemination scheme for state propagation of available blocks and initiation of block transmissions. In order to exploit heterogeneity of peers, enhance the utilization of system resources and for the ease of deployment, scalability, and adaptivity to dynamic peer arrivals/departures, we propose mechanisms for adjusting protocol parameters dynamically according to the bandwidth usages. We describe design and analysis details of our protocol SeCond. Comprehensive performance evaluations and comparison with the BitTorrent system model have been accomplished for a wide range of scenarios. Performance results include scalability analysis for different arrival/departure patterns, flash-crowd scenario, overhead analysis, and fairness ratio. The major metrics we study include the average file download time, load on the primary seed, uplink/downlink utilization, and communication overhead. We show that SeCond is a scalable and adaptive protocol which takes the heterogeneity of the peers into account. The protocol is as fair as BitTorrent although it has no explicit strategy addressing free-riding. We also illustrate the applicability of an analytical fluid model to the behavior of SeCond.

Resource search in unstructured peer-to-peer system based on multiple-tree overlay structure

We propose a multiple-tree overlay structure for resource discovery in unstructured P2P systems. Peers that have similar interests or hold similar type of resources will be grouped into a tree-like cluster. We exploit the heterogeneity of peers in each cluster by connecting peers with more capacities closer to the root of the tree. The capacity of a peer can be defined in different ways (e.g. higher network bandwidth, larger disk space, more data items of a certain type etc.) according to different needs of users or applications.

AntSearch: An Ant Search Algorithm in Unstructured Peer-to-Peer Networks

The most prevalent peer-to-peer (P2P) application till today is file sharing, and unstructured P2P networks can support inherent heterogeneity of peers, are highly resilient to peers' failures, and incur low overhead at peer arrivals and departures. Dynamic querying (DQ) is a new flooding technique which could estimate a proper time-to-live (TTL) value for a query flooding by estimating the popularity of the searched files, and retrieve sufficient results under controlled flooding range for reducing network traffic. Recent researches show that a large amount of peers in the P2P file sharing system are the free-riders, and queries are seldom hit by those peers. The free-riding problem causes a large amount of redundant messages in the DQ-like search algorithm. In this paper, we proposed a new search algorithm, called to solve the problem. In AntSearch, each peer maintains its hit rate of previous queries, and records a list of pheromone values of its immediate neighbors. Based on the pheromone values, a query is only flooded to those peers which are not likely to be the free-riders. Our simulation results show that, compared with DQ and its enhanced algorithm DQ+, the AntSearch algorithm averagely reduces 50% network traffic at almost the same search latency as DQ+, while retrieving sufficient results for a query with a given required number of results.

A Scalable Peer-to-Peer Architecture for Distributed Information Monitoring Applications

We present PeerCQ, a decentralized architecture for Internet scale information monitoring using a network of heterogeneous peer nodes. PeerCQ uses continual queries (CQs) as its primitives to express information-monitoring requests. The PeerCQ development has three unique characteristics. First, we develop a systematic and serverless approach to large scale information monitoring, aiming at providing a fully distributed, highly scalable, and self-configurable architecture for scalable and reliable processing of a large number of CQs over a network of loosely coupled, heterogeneous, and possibly unreliable nodes (peers). Second, we introduce an effective service partitioning scheme at the P2P protocol layer to distribute the processing of CQs over a peer-to-peer information monitoring overlay network while maintaining a good balance between system utilization and load balance in the presence of peer joins, departures, and failures. A unique feature of our service partitioning scheme is its ability to incorporate strategies for handling hot spot monitoring requests and peer heterogeneity into the load balancing scheme in PeerCQ. Third, but not least, we develop a dynamic passive replication scheme to enable reliable processing of long-running information monitoring requests in an environment of inherently unreliable peers, including an analytical model to discuss its fault tolerance properties. We report a set of experiments demonstrating the feasibility and the effectiveness of the PeerCQ approach to large-scale peer-to-peer information monitoring.

Peering by exploiting peer heterogeneity

Resource discovery in peer‐to‐peer (P2P) systems have been extensively studied. Unfortunately, most of the systems studied are not designed to take advantage of the heterogeneity in peer nodes. In this paper, we propose a novel P2P overlay called RATTAN, which serves as an underlay of a Gnutella‐like network. RATTAN exploits the heterogeneity of peer nodes by structuring capable nodes as the core of the overlay. Using a tree‐like structure, RATTAN can maximize the search scope with a minimal number of query messages. We evaluate RATTAN with simulation. The experiments show the following interesting results. First, RATTAN is robust by exploiting redundant overlay links. Second, the maximum bandwidth demand for processing the protocol of a single RATTAN overlay is nearly 1M bits/sec. However, around 80% of the nodes merely take 66 bits/sec. One implication is that we can use a small number of relatively capable peers (e.g., stable machines with a 100M bits/sec network interface) to process the 1M bits/sec protocol overhead and serve other peers that only need to spend 66 bits/sec for processing protocol overhead.

A hybrid architecture for cost-effective on-demand media streaming

We propose a new architecture for on-demand media streaming centered around the peer-to-peer (P2P) paradigm. The key idea of the architecture is that peers share some of their resources with the system. As peers contribute resources to the system, the overall system capacity increases and more clients can be served. The proposed architecture employs several novel techniques to: (1) use the often-underutilized peers’ resources, which makes the proposed architecture both deployable and cost-effective, (2) aggregate contributions from multiple peers to serve a requesting peer so that supplying peers are not overloaded, (3) make a good use of peer heterogeneity by assigning relatively more work to the powerful peers, and (4) organize peers in a network-aware fashion, such that nearby peers are grouped into a logical entity called a cluster. The network-aware peer organization is validated by statistics collected and analyzed from real Internet data. The main benefit of the network-aware peer organization is that it allows to develop efficient searching (to locate nearby suppliers) and dispersion (to disseminate new files into the system) algorithms. We present network-aware searching and dispersion algorithms that result in: (i) fast dissemination of new media files, (ii) reduction of the load on the underlying network, and (iii) better streaming service. We demonstrate the potential of the proposed architecture for a large-scale on-demand media streaming service through an extensive simulation study on large, Internet-like, topologies. Starting with a limited streaming capacity (hence, low cost), the simulation shows that the capacity rapidly increases and many clients can be served. This occurs for all studied arrival patterns, including constant rate arrivals, flash crowd arrivals, and Poisson arrivals. Furthermore, the simulation shows that a reasonable client-side initial buffering of 10–20 s is sufficient to ensure full quality playback even in the presence of peer failures.