Application-layer Overlay Networks Research Articles

Cost-Effective Resource Allocation of Overlay Routing Relay Nodes A Survey

Today Internet is a very popular and vastly growing application. It added support for various new services as compared to past 3 decades Internet. The services like mobility, real time support and much more requires continuous evolution in Internet techniques and infrastructure. As number of users increasing day by day, Internet suffers from various problems such as bottleneck, congestion, path and server failure etc. To overcome or minimize these problems Internet wants new schemes with little or no change in present routing infrastructure. Overlays are the best solution; which provides new functionalities and improves previous properties without making any change in routing standards and network infrastructure. Overlay is an additional virtual layer providing new functionalities to present routing infrastructure. Overlay network constructed on top of surviving network. Some present overlay networks are oTCP, RON, Detour, G-ISP designed to provide some functionalities. oTCP is an Overlay network, it increase TCP performance of connection by converting a TCP connection into multiple pipelined sub-connection. Each sub-connection follows end to end nature of TCP. RON is designed to provide fast fault recovery. RON is an application layer overlay network so it route packet according to application specific routing metrics. Instead of dedicated links Detour takes alternate paths to increase performance and availability. Detour routers form a virtual layer of functionality by tunneling packets over standard Internet. The inter-domain routing functionalities such as end to end inter-AS QoS, multicasting are offered by G-ISP to its customers , which today's Internet doesn't provide.

Multicasting over Overlay Networks - A Critical Review

Multicasting technology uses the minimum network resources to serve multiple clients by duplicating the data packets at the closest possible point to the clients. This way at most only one data packets travels down a network link at any one time irrespective of how many clients receive this packet. Traditionally multicasting has been implemented over a specialized network built using multicast routers. This kind of network has the drawback of requiring the deployment of special routers that are more expensive than ordinary routers. Recently there is new interest in delivering multicast traffic over application layer overlay networks. Application layer overlay networks though built on top of the physical network, behave like an independent virtual network made up of only logical links between the nodes. Several authors have proposed systems, mechanisms and protocols for the implementation of multicast media streaming over overlay networks. In this paper, the author takes a critical look at these systems and mechanism with special reference to their strengths and weaknesses.

A survey on the design, applications, and enhancements of application-layer overlay networks

This article presents a survey of recent advancements in application-layer overlay networks. Some of the most important applications that have been proposed for overlays include multicast, QoS support, denial-of-service (DoS) defense, and resilient routing. We look at some of the important approaches proposed for these applications and compare the advantages and disadvantages of these approaches. We also examine some of the enhancements that have been proposed in overlay topology design, enhanced routing performance, failure resistance, and the issues related to coexistence of overlay and native layers in the Internet. We conclude the article with a comment on the purist vs pluralist argument of overlay networks that has received much debate recently. Finally, we propose a new deployment model for service overlays that seeks to interpose between these two approaches.

MTreebone: A Collaborative Tree-Mesh Overlay Network for Multicast Video Streaming

Recently, application-layer overlay networks have been suggested as a promising solution for live video streaming over the Internet. To organize a multicast overlay, a natural structure is a tree, which, however, is known vulnerable to end-hosts dynamics. Data-driven approaches address this problem by employing a mesh structure, which enables data exchanges among multiple neighbors, and thus, greatly improves the overlay resilience. It unfortunately suffers from an efficiency-delay trade-off, because data have to be pulled from mesh neighbors by using extra notifications periodically. In this paper, we closely examine the contributions of overlay nodes, and argue that performance of a mesh overlay closely depends on a small set of stable backbone nodes. This is validated through a real trace study on PPLive, the largest commercial application-layer live streaming system to date. Motivated by this observation, we then suggest a novel collaborative tree-mesh design that leverages both mesh and tree structures. The key idea is to identify a set of stable nodes to construct a tree-based backbone, called treebone, with most of the data being pushed over this backbone. These stable nodes, together with others, are further organized through an auxiliary mesh overlay, which facilitates the treebone to accommodate node dynamics and fully exploit the available bandwidth between overlay nodes. This hybrid design, referred to as mTreebone, brings a series of unique and critical design challenges. In particular, the identification of stable nodes and seamless data delivery using both push and pull methods. In this paper, we present optimized solutions to these problems, which reconcile the two overlays under a coherent framework with controlled overhead. We evaluate mTreebone through both simulations and PlanetLab experiments. The results demonstrate the superior efficiency and robustness of this hybrid solution in both static and dynamic scenarios.

A Dynamic Skip List-Based Overlay for On-Demand Media Streaming with VCR Interactions

Media distribution through application-layer overlay networks has received considerable attention recently, owing to its flexibility and readily deployable nature. On-demand streaming with asynchronous requests and, in general, with VCR-like interactions nevertheless remains a challenging task in overlay networks. In this paper, we introduce the dynamic skip list (DSL), a novel randomized and distributed structure that inherently accommodates dynamic and asynchronous clients. We establish the theoretical foundations of the DSL and demonstrate a practical DSL-based streaming overlay. In this overlay, the costs for typical operations, including join, leave, fast-forward, rewind, and random seek, are all sublinear to the client population. The model also seamlessly integrates a smart data scheduling algorithm using linear network coding, yielding fast and robust downloading from multiple suppliers. Our simulation results show that the DSL-based overlay is highly scalable. It delivers reasonably smooth playback with diverse client interactivities while keeping the computation and bandwidth overheads low.

On the analysis of overlay failure detection and recovery

Application-layer overlay networks have been proposed as an alternative method to overcome IP-layer path anomalies and provide users with improved routing services. Running at the application layer, overlay networks usually rely on probing mechanisms for IP-path performance monitoring and failure detection. Their service performance is jointly determined by their topology, parameters of probing mechanism and failure restoration methods. In this paper, we first define metrics to evaluate the performance of overlay networks in terms of failure detection and recovery, network stability and overhead. Second, we model the overlay-based failure detection and recovery process. Through extensive simulations, we investigate how different IP-layer path failure characteristics and overlay topologies, detection and restoration parameters affect service performance of overlay networks. In particular, we examine the tradeoffs among different overlay performance metrics and the optimal performance conditions. Our study helps to understand overlay-based failure recovery and provides practical guidance to overlay network designers and administrators.

OEvolve : Toward Evolutionary Overlay Topologies for High-Bandwidth Data Dissemination

In this paper, we consider the problem of data dissemination from a source to multiple receivers over application-layer overlay networks, and seek to significantly improve end-to-end throughput of data dissemination sessions by constructing topologies of high quality. We propose oEvolve, a distributed algorithm that uses the strategy of progressively and adaptively evolving the overlay topology over time toward high-quality topologies, especially with respect to end-to-end throughput of data dissemination. To validate the effectiveness and efficiency of oEvolve, we present a fully distributed real-world oEvolve implementation over PlanetLab , a global-scale wide-area overlay network testbed. Our implementation consists of a framework of components that involves a high-performance data forwarding engine and a centralized performance monitoring facility.

OStream: Asynchronous Streaming Multicast in Application-Layer Overlay Networks

Although initially proposed as the deployable alternative to Internet protocol multicast, the application-layer overlay network actually revolutionizes the way network applications can be built, since each overlay node is an end host and is able to carry out more functions than simply forwarding packets. The paper addresses the on-demand media distribution problem in the context of an overlay network. We take advantage of the strong buffering capabilities of end hosts, and propose a novel overlay multicast strategy, oStream. We have performed extensive analysis and performance evaluation with respect to the scalability and the efficiency of oStream. With respect to the required server bandwidth, we show that oStream defeats the theoretical lower bound of traditional multicast-based approaches, under both sequential and nonsequential stream access patterns. oStream is also robust against bursty requests. With respect to bandwidth consumption on the backbone network, we show that the benefit introduced by oStream overshadows the topological inefficiency (e.g., link stress and stretch) introduced by using application-layer multicast.

Multicast With Network Coding in Application-Layer Overlay Networks

All of the advantages of application-layer overlay networks arise from two fundamental properties: 1) the network nodes in an overlay network, as opposed to lower-layer network elements such as routers and switches, are end systems and have capabilities far beyond basic operations of storing and forwarding; 2) the overlay topology, residing above a densely connected Internet protocol-layer wide-area network, can be constructed and manipulated to suit one's purposes. We seek to improve end-to-end throughput significantly in application-layer multicast by taking full advantage of these unique characteristics. This objective is achieved with two novel insights. First, we depart from the conventional view that overlay nodes can only replicate and forward data. Rather, as end systems, these overlay nodes also have the full capability of encoding and decoding data at the message level using efficient linear codes. Second, we depart from traditional wisdom that the multicast topology from source to receivers needs to be a tree, and propose a novel and distributed algorithm to construct a two-redundant multicast graph (a directed acyclic graph) as the multicast topology, on which network coding is applied. We design our algorithm such that the costs of link stress and stretch are explicitly considered as constraints and minimized. We extensively evaluate our algorithm by provable analytical and experimental results, which show that the introduction of two-redundant multicast graph and network coding may indeed bring significant benefits, essentially doubling the end-to-end throughput in most cases.