Application-level Multicast Research Articles

Context-aware RAON middleware for opportunistic network

Application development and deployment on Mobile Ad Hoc Networks (MANET) is a major challenge in the widespread use of MANET. The increasing D2D communication in 5G networks has renewed interest in an effective middleware design for MANET where application developers face various challenges such as unstable connectivity, high error rate, mobility induced disruption and disconnection, and limited battery power. We find that unstructured overlay network provides a good abstraction to facilitate application development and deployment on MANET. In this paper, we present the design of a middleware that builds a Resource-Aware Overlay Network (RAON), which is an unstructured overlay network of nodes engaged in the application that employs a query–reply mechanism for resource discovery. RAON is enhanced with features such as proactive neighbor replacement, congestion-aware data download and cooperative caching. Simulation results show that these features are effective in reducing query delay, improving data availability, and balancing node power consumption with protocol performance. We also present the middleware software design that offers the API based on node and path abstractions to applications. The middleware implements a generic context framework for acquiring device and user context. We discuss the implementation of application-level multicast and credit-based file-sharing applications using the middleware API. The middleware is implemented in Java J2ME on Android, which is tested in an ad hoc network of Nexus 7 devices running OLSR.

The Application Level Multicast Technique Algorithms Oriented to P2P Video

Firstly challenges in P2P media streaming applications were pointed out, then some recent research results such as application-level multicast tree, heterogeneity of network and incentive mechanism and so on were introduced. This paper has proposed a new model of application level multicast named DHCM (density-based hierarchical clustering multicast)which has improved IHC arithmetic．DHCM divides the hosts into many hierarchies according to their density，and constructs a density tree to realize the shortest routing．The tree delivers the content of video server to each host in density tree and uses a P2P scheme in data transmission．By this way the application-level multicast has been realized．This density tree has the homogeneity and monotonic properties．The experiment result has proved that DHCM can transmit the video stream efficiently and robustly.

A Media Stream Multicast Model Based on Proxy

Although Application-level multicast is a new multi-point data transmission model, there is no mature and effective scheme for network heterogeneity problem. This paper proposes an agent-based adaptive media multicast system, i.e., the so-called iPALM system (Proxy based Application-level Multicast). It uses efficiently data transmission of IP multicast in LAN, and every IP multicast area sets one agent server named MPN, the backbone network composed of MPNs transmits data using application-level multicast. At the same time, iPALM provides the head format of system protocol, and the definition of transmission message in XML format which demonstrates that iPALM system can satisfy every different application requirement, and improves the media service quality in heterogeneous environment.

A new Application-Level Multicast technique for stable, robust and efficient overlay tree construction

Even though Application Level Multicast (ALM) protocols are proposed as an efficient alternative to the classical IP multicast model, they still suffer from the same rearrangement overhead problem. Indeed, when a member joins or leaves the multicast session, a part of the overlay tree should be rearranged. This rearrangement overhead can significantly disturb the fluidity of the application data stream received by other members. In addition, the efficiently of the constructed overlay tree depends entirely on the honesty and the cooperation of all participating members. However such behavior cannot be guaranteed and some selfish and non-cooperative nodes may take profit from the honesty of other members in the overlay. In this paper we present a new technique, called Membership Duration Aware ALM (MDA technique), that takes advantage of the announced membership duration of each new joining member in order to construct a more stable and robust overlay trees. Our technique can be used together with any existing centralized or distributed ALM protocol to reduce the overall rearrangement overhead. Simulation results confirm the efficiency of our technique when applied to both centralized and distributed ALM protocol. Then, we analyze in depth the impact of cheating nodes on the performances and the stability of overlay trees constructed by our MDA-ALM protocol.

Agent based infrastructure for real-time applications

In this paper we propose a new infrastructure for real-time applications. As a preliminary, we describe basic characteristics of the most popular real-time services like VoIP, videoconferencing, live media streaming, and network multiplayer games. We focus on the end-to-end latency, bandwidth and efficient transmission methods. Next, we present our project concepts, infrastructure model, details of implementation and our testing environment which was designed for testing many aspects of real-time services. The system combines mechanisms for ensuring best possible connection quality (QoS), load balance of servers in infrastructure and gives control over the packet routing decisions. Additionally, provided security mechanisms make it a good choice even in the environment where a high security level is required. The system is based on the Peer-to-Peer (P2P) model and data between users is routed over an overlay network, consisting of all participating peers as network nodes. This overlay can by used for application level multicast or live media stream. In the logging process each user is assigned to a specific node (based on his geographic location and nodes load). Because nodes are participating in data transmission, we have control over the data flow route. It is possible to specify the desired route, so, regardless of the external routing protocol, we can avoid paths that are susceptible to eavesdropping. Another feature of the presented system is usage of agents. Each agent acts within the single node. Its main task is to constantly control the quality of transmission. It analyzes such parameters like link bandwidth use, number of lost packets, time interval between each packet etc. The information collected by the agents from all nodes allows to build a dynamic routing table. Every node uses the Dijkstra's algorithm to find the best at the moment route to all other nodes. The routes are constantly modified as a consequence of changes found by agents or updates sent by other nodes. In VoD services agents also analyze popularity of streamed media, which helps build intelligent video cache. To ensure greater security and high reliability of the system, we have provided a reputation mechanism. It is used during bringing up to date the information about possible routes and their quality, given by other nodes. Owing to this solution nodes and routes which are more reliable get higher priority.

Minimising delay for video conference with network coding

Video conference is an attractive and promising application which allows immersive communication and discussion among people at different and distant places. However, its stringent delay and bandwidth requirements limit its scale and spread over current internet. This paper attempts to introduce the prosperous technology of network coding (NC) into video conference to minimise the maximal transmission delay between source and all the participants while retaining high bandwidth utilisation at the same time. Extensive numerical analysis and PlanetLab experiments demonstrate that the proposed innovative NC scheme can significantly improve the delay performance for video conference like multi-party interactive multimedia applications than conventional application level multicast.

PPmcast: a novel P2P-based application-level multicast using Kamulia

The rapid growth and popularity of networked meeting environments such as video conference in recent years have spawned a series of research interests in constructing large-scale environments. For increasing scalability and decreasing the cost of management and deployment, more and more studies propose using peer-to-peer (P2P) architectures to construct large-scale application-level multicast algorithm for games, multimedia and other applications. In order to improve the applications' performance, high efficiency multicast algorithm is required. This paper focuses on developing a novel P2P application-level multicast algorithm based on Kamulia protocol. In the proposed algorithm, all nodes of P2P network are organized into structured overlay network by distributed hash table (DHT). The distance metric between two nodes is obtained by computing the exclusive or (XOR) value. The theoretical analysis indicates the proposed algorithm has better time complexity degree compared with other similar algorithms. The simulation experiments also show that the proposed algorithm has better performance on the following aspects, control expenses, loss ratio after failure, and waiting time to the first packet.

A Self-organized Clustering-based Overlay Network for Application Level Multicast

Peer-to-Peer Overlay networks enabling an end-end application level-multicast service have drawn enormous attention. This paper proposes a self-organized -Multicast Overlay Network ( - MON) that enables an efficient end-end application level multicast. The -MON is organized into MON-Clusters, where δ is the maximum physical number of hops between any two end-nodes in each MON-Cluster. Thus, end-users accessing from different areas are able to broadcast data into each MON-Cluster within a constant δ physical number of hops. However in a dense-mode, increasing the size of MON-Clusters induces a long logical diameter that manifests high stress per physical links and high delay to disseminate data. Thus, this paper limits the expansion of each MON-Cluster within a specific logical diameter μ. Each MON-Cluster is constructed with at most μ logical hops over δ physical hops. Thus, end-users are able to efficiently disseminate data into each MON-Cluster within μ logical hops over δ physical hops with reasonable stress per physical links and bandwidth consumption.

Editorial: Special issue on mobile P2P networking and computing

Peer-to-Peer networking first emerged as an overlay technique to support distributed file sharing over the Internet. Since then, P2P networking and computing have gradually evolved into a system framework that delivers a broad range of distributed and scalable resource discovery and sharing applications including efficient search of data items and people using context/key based routing, application level multicast, redundant storage, video streaming, etc. Striving for automated formation, distributed operation and effective resource sharing, peers form self-organizing overlay networks and offer services beyond the traditional client-server paradigm of Internet by entrusting symmetry in roles and requiring no or fewer pre-established servers. Today, mobile end devices are one of the major participants in information gathering, processing, dissemination and consumption. Supporting the P2P networking and computing paradigm in this ever growing mobile communications environment has become an appealing idea. The key attraction of the Mobile P2P (MP2P) paradigm is its ability to scale without requiring expensive and manually configured servers, and to sustain failure points through automatic recovery of a fully distributed structure. Compared with wired networks, it is generally more difficult to set up and maintain centralized servers in some mobile networks, such as in the Mobile Ad hoc Network (MANET). It may also be generally possible to harvest efficiency gains through sharing applications and contents among peer mobile end devices directly rather than backhauling them to a centralized server in the fixed backbone network. Though the P2P paradigm may naturally suit well the distributed and dynamic wireless communications environment, support of MP2P is particularly challenging considering the special characteristics of the mobile networks. The highly variable connectivity, frequent disconnection, locationdependency, energy and resource constraints, diversity in wireless end devices and as well the carrier-grade performance requirements when offering business level applications bring about some critical issues in facilitating the MP2P paradigm. The mobility of the users may increase dramatically the churn in the peer systems to engender extra overhead when employing P2P overlay protocols. The limited bandwidth and constrained battery resource available to the wireless device aggravate the hindrance and may even render the P2P overlay mechanism infeasible in operation. Due to resource limitations, mobile peers can be inclined to the selfish freerider behaviour in data sharing and downloading. The Peer-to-Peer Netw Appl (2009) 2:179–181 DOI 10.1007/s12083-009-0040-z

TKS: a transition key management scheme for secure application level multicast

The Application Level Multicast (ALM) simplifies the implementation of group communication. However, it still suffer from the same management overhead in case of highly dynamic sessions. In this paper, we propose an efficient key management protocol, called Transition Key Scheme (TKS), for ALM communication. TKS aims to reduce the key management overhead in case of highly dynamic membership sessions by using a unique Traffic Encryption Key (TEK), for the group, and a small number of individual transition keys to temporally manage members who recently joined the group. Simulation results confirm that TKS reduces significantly key management overhead, compared to other existing ALM key management protocols. In addition, we validated our scheme using AVISPA validation tool, and the results show that TKS is safe against intruder attacks.

Cheatproof Dual-Tree Application-Level Multicast for Bulk Data Distribution

Application-level multicast has drawn a lot of attention as an alternative to IP multicast. In application-level multicast, multicast related features, such as group membership management, packet replication and packet forwarding are implemented at end-hosts instead of routers. The host perceived transmission quality and multicast forwarding responsibility depend on its position in the multicast distribution tree. This nature of application-level multicast motivates selfish members to alter their position by unrightful means to maximize their private benefits. Uncooperative behaviors of these selfish members, i.e. cheating, increase unfairness between selfish members and faithful members. In the context of bulk data distribution, this unfairness between members significantly impacts the receiver throughput. In this paper, to alleviate the negative impact of cheating members, we propose a new tree building protocol which builds dual multicast trees. Our proposed protocol constructs a shortest-widest path tree as the 1st tree. The members having lower position in the 1st tree are located at higher position in the 2nd tree in exchange for their unfairness. To investigate performance of our proposed protocol, it is compared with the existing application-level multicast protocol. Our simulation results show that our protocol outperforms the existing protocol from the view point of throughput and resource utilization against member cheating.

The Orchard Algorithm: Building Multicast Trees for P2P Video Multicasting Without Free-Riding

The main purpose of many current peer-to-peer (P2P) networks is off-line file sharing. However, a potentially very promising use of such networks is to share video streams (e.g., TV programs) in real time. In order to do so, the peers in a P2P network who are interested in the same video stream may employ Application Level Multicasting (ALM). In existing P2P networks, peers may exhibit behavior which is problematic for ALM: they are not always willing to donate resources (free-riding), and they may arrive and depart at a high rate (churn). In this paper we propose the Orchard algorithm for creating and maintaining ALM trees in P2P networks, which deals with both these problems. By employing a technique called Multiple Description Coding, we split a video stream into several substreams. Orchard creates a dynamic spanning tree for each of these substreams in such a way that in the resulting forest, no peer has to forward more substreams than it receives. Based on an analysis of the expected performance of Orchard and on experiments in a real system, we find that Orchard is capable of maintaining a multicast forest, even when peers join and leave the forest at a high rate.

DirectStream: A directory-based peer-to-peer video streaming service

Providing video streaming service over the Internet is a challenging task. Recent works show that peer-to-peer networking is a promising technique to address the scalability issues faced by video streaming service. Peer-to-peer video streaming allows users distributed across the Internet to collaborate and bring computation and storage resources into the system, hence reducing the workload placed on the server and increasing the number of clients served. In this paper, we propose DirectStream, a directory-based peer-to-peer video streaming service that efficiently and cost-effectively provides video-on-demand service with VCR operation support. In addition, we develop an application-level multicast based directory service tailored for DirectStream, known as AMDirectory service. We analytically and experimentally examine the system performance, and show that the proposed scheme significantly reduces the workload posed on the origin server, and that it scales extremely well as the popularity of the video increases even if participating clients behave non-cooperatively. Furthermore, AMDirectory service allows DirectStream to perform well in the face of a large number of concurrent users. We also discuss how DirectStream supports basic VCR operations, and provides continuous playback in the presence of the users’ early departures and bandwidth starvation.

PeerCast: Churn-resilient end system multicast on heterogeneous overlay networks

The lack of wide deployment of IP multicast in the Internet has prompted researchers to propose end system multicast or application-level multicast as an alternate approach. However, end system multicast, by its very nature, suffers from several performance limitations, including, high communication overheads due to duplicate data transfers over same physical links, uneven load distribution caused by widely varying resource availabilities at nodes, and highly failure-prone nature of end-hosts. This paper presents a self-configuring, efficient and churn-resilient end-system multicast system called PeerCast. Three unique features distinguish PeerCast from existing approaches to application-level multicasting. First, with the aim of exploiting network proximity of end-system nodes for efficient multicast subscription management and fast information dissemination, we propose a novel Internet-landmark signature technique to cluster the end-hosts of the overlay network. Second, we propose a capacity aware overlay construction technique to balance the multicast workload among heterogeneous end-system nodes. Third, we develop a dynamic passive replication scheme to provide reliable end system multicast services in an inherently dynamic environment of unreliable peers. We also present a set of experiments showing the feasibility and the effectiveness of the proposed mechanisms and techniques.

Application of Peer-to-Peer Network for Real-Time Online Collaborative Computer-Aided Design

The Internet has revolutionized the way software systems work. Many applications, such as online games and instant messengers, have utilized Web-related technologies to cooperate over the Internet. Recently, some researchers have utilized Web-related technologies in computer-aided design to allow real-time collaboration between users over the Web. All these systems are based on the client-server model. In this kind of collaborative design environment, the system grouping, operation, and communication all have to rely on the central server. In order to improve accessibility and flexibility in collaborative design and to provide a more load-balanced and extensible environment, this paper presents a prototype implementation of collaborative design tools based on a peer-to-peer (P2P) model. The users can conveniently form design groups by connecting directly to each other, anytime and anywhere, without the presence of a central server. All peers are equal in functionalities and computing loads. In addition, application level multicast (ALM) technology is adopted in the proposed system to improve efficiency in Internet communication. Based on the P2P network model and ALM communication scheme, several mechanisms are proposed in this paper to form a working model of this system. Then, the object model design and implementation of this P2P system is presented.

Advanced networking services for distributed multimedia streaming applications

Increased network speeds coupled with new services delivered via the Internet have increased the demand for intelligence and flexibility in network systems. This paper argues that both can be provided by new hardware platforms comprised of heterogeneous multi-core systems with specialized communication support. We present and evaluate an experimental network service platform that uses an emergent class of devices--network processors--as its communication support, coupled via a dedicated interconnect to a host processor acting as a computational core. A software infrastructure spanning both enables the dynamic creation of application-specific services on the network processor, mediated by middleware and controlled by kernel-level communication support. Experimental evaluations use a Pentium IV-based computational core coupled with an IXP 2400 network processor. The sample application services run on both include an image manipulation application and application-level multicasting.

Algorithms and Trade-Offs in Multicast Service Overlay Design

The Multicast Service Overlay Network (MSON) has been recently introduced to address some of the deployment and maintenance problems of IP multicast and application-level multicast. An MSON is essentially a backbone service overlay provisioned by an MSON provider and designed to “multiplex” multiple-user overlays. It consists of service nodes or proxies deployed by the provider. The proxies are strategically deployed to form a backbone overlay and provide multicasting functionalities for supporting many user groups simultaneously. The MSON provider designs the backbone overlay for a large user population and can therefore enjoy large-scale economies and benefits. Since the deployment of an MSON is a capital-intensive investment, it is very imperative to carefully design the MSON so that the provider can make the best revenue out of this investment. In this article, the authors formulate the MSON design problem by taking into account operational costs of the MSON provider. They then explore three subproblems: overlay proxy placement, overlay link selection, and bandwidth dimensioning. For each of these subproblems, the authors present several algorithms and discuss their design trade-offs. By simulations, they investigate the effectiveness of different overlay design algorithms, analyze their impact on multicast performance, and suggest some practical solutions for MSON design.

Lateral error recovery for media streaming in application-level multicast

We consider media streaming using application-level multicast (ALM) where packet loss has to be recovered via retransmission in a timely manner. Since packets may be lost due to congestion, node failures, and join and leave dynamics, traditional "vertical" recovery approach where upstream nodes retransmit the lost packets is no longer effective. We therefore propose lateral error recovery (LER). In LER, hosts are divided into a number of planes, each of which forms an independent ALM tree. Since error correlation across planes is low, a node effectively recovers its error by "laterally" requesting retransmission from nearby nodes in other planes. We present analysis on the complexity and recovery delay on LER. Using Internet-like topologies, we show via simulations that LER is an effective error recovery mechanism. It achieves low overhead in terms of delivery delay (i.e., relative delay penalty) and physical link stress. As compared with traditional recovery schemes, LER attains much lower residual loss rate (i.e., loss rate after retransmission) under a certain deadline constraint. The performance can be substantially improved in the presence of some reliable proxies.

Explicit routing in multicast overlay networks

Application Level Multicast is a promising approach to overcome the deployment problems of IP level multicast by establishing delivery trees using overlay links among end systems. This paper presents algorithms to support traffic engineering, to improve the reliability of multicast delivery, and to facilitate secure group communications. First, we introduce the so-called backup multicast tree algorithm to compute a set of n − 1 backup multicast delivery trees from the default multicast tree. Each backup multicast tree has exactly one link of the default multicast tree that is replaced by a backup link from the set of available links. The algorithm can calculate this set of trees with a complexity of O ( m log n), which is identical with the complexity of well known minimum spanning tree algorithms. The so-called reduced multicast tree algorithm is based on the backup multicast tree algorithm and can calculate a tree from the default multicast tree by removing a particular node and by replacing the links of the removed node. Using the algorithms trees can be calculated individually by each of the nodes but it requires global topology knowledge. We therefore discuss distributed versions of the algorithms.

Construction of a Robust Multicast Tree for Application-Level Multicast

Application-level multicast (ALM) is a feasible alternative to IP multicast. In ALM, multicast related features, such as group membership management, multicast routing and packet replication, are implemented at end-hosts instead of routers. A multicast distribution tree is constructed in the application layer, so all nodes in this tree are end-hosts. Packet transmission between end-hosts uses conventional IP unicast service. Therefore, all end-hosts can enjoy multicast communications without IP multicast service. However, ALM has a serious problem that the multicast distribution tree is intrinsically fragile and an end-host failure causes tree partitions. In this paper, to deal with this problem, we propose a new tree construction protocol which makes outdegrees of intermediate nodes be balanced. The degree-balanced distribution tree can reduce the average number of nodes decoupled by tree partitions. To investigate performance of our protocol, it is compared with an existing ALM protocol. Our simulation results show that our protocol outperforms the existing protocol from the viewpoints of robustness, loss probability and receiver-perceived delay.