NETEMBED: A Network Resource Mapping Service for Distributed Applications

Emerging configurable infrastructures such as large-scale overlays and grids, distributed testbeds, and sensor networks comprise diverse sets of available computing resources (e.g., CPU and OS capabilities and memory constraints) and network conditions (e.g., link delay, bandwidth, loss rate, and jitter) whose characteristics are both complex and time-varying. At the same time, distributed applications to be deployed on these infrastructures exhibit increasingly complex constraints and requirements on resources they wish to utilize. Examples include selecting nodes and links to schedule an overlay multicast file transfer across the Grid, or embedding a network experiment with specific resource constraints in a distributed testbed such as PlanetLab. Thus, a common problem facing the efficient deployment of distributed applications on these infrastructures is that of "mapping" application-level requirements onto the network in such a manner that the requirements of the application are realized, assuming that the underlying characteristics of the network are known. We refer to this problem as the network embedding problem. In this paper, we propose a new approach to tackle this combinatorially-hard problem. Thanks to a number of heuristics, our approach greatly improves performance and scalability over previously existing techniques. It does so by pruning large portions of the search space without overlooking any valid embedding. We present a construction that allows a compact representation of candidate embeddings, which is maintained by carefully controlling the order via which candidate mappings are inserted and invalid mappings are removed. We present an implementation of our proposed technique, which we call NETEMBED – a service that identify feasible mappings of a virtual network configuration (the query network) to an existing real infrastructure or testbed (the hosting network). We present results of extensive performance evaluation experiments of NETEMBED using several combinations of real and synthetic network topologies. Our results show that our NETEMBED service is quite effective in identifying one (or all) possible embeddings for quite sizable queries and hosting networks – much larger than what any of the existing techniques or services are able to handle.National Science Foundation (CNS Cybertrust 0524477, NSF CNS NeTS 0520166, NSF CNS ITR 0205294, EIA RI 0202067

Network Architectures for Live Peer-to-Peer Media Streaming

Peer-to-Peer (P2P) media streaming networks, motivated by the huge success of P2P file downloading networks, have recently attracted a lot of research interest. However, it is challenging to design P2P media streaming networks because of the stringent time constraints on the delivered media streams, which require more efficient and resilient overlay architectures. In this paper, we focus on live P2P media streaming networks, a promising application flourishing in the Internet and which requires the distribution of live (not stored) multimedia content to subscribers. We review the architectures for live P2P media streaming networks, and consider both overlay topologies and their construction

View-Upload Decoupling: A Redesign of Multi-Channel P2P Video Systems

Abstract—In current multi-channel live P2P video systems, there are several fundamental performance problems including exceedingly-large channel switching delays, long playback lags, and poor performance for less popular channels. These performance problems primarily stem from two intrinsic characteristics of multi-channel P2P video systems: channel churn and channelresource imbalance. In this paper, we propose a radically different cross-channel P2P streaming framework, called View-Upload Decoupling (VUD). VUD strictly decouples peer downloading from uploading, bringing stability to multichannel systems and enabling cross-channel resource sharing. We propose a set of peer assignment and bandwidth allocation algorithms to properly provision bandwidth among channels, and introduce substream swarming to reduce the bandwidth overhead. We evaluate the performance of VUD via extensive simulations as well with a PlanetLab implementation. Our simulation and PlanetLab results show that VUD is resilient to channel churn, and achieves lower switching delay and better streaming quality. In particular, the streaming quality of small channels is greatly improved. I

Collaborative communications among multiple points.

Zhang Xinyan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves [78]-[85]).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Multiple Point Communication --- p.1Chapter 1.2 --- Major Contributions --- p.2Chapter 1.3 --- Thesis Organization --- p.4Chapter 2 --- Related Work --- p.5Chapter 2.1 --- Peer-to-Peer Networks --- p.5Chapter 2.2 --- Application Layer Multicast --- p.11Chapter 2.3 --- Internet Traffic Engineering --- p.19Chapter 3 --- MultiServ: Application Layer Multiple Path Routing --- p.23Chapter 3.1 --- Motivation --- p.24Chapter 3.2 --- MultiServ Overlay Construction --- p.28Chapter 3.3 --- MultiServ Routing --- p.33Chapter 3.3.1 --- The importance of routing strategy --- p.33Chapter 3.3.2 --- Solutions for IP network --- p.35Chapter 3.3.3 --- MultiServ routing --- p.37Chapter 3.3.4 --- MultiServ routing with bounded complexity --- p.39Chapter 3.3.5 --- Routing implementation --- p.41Chapter 3.4 --- Performance Evaluation --- p.45Chapter 3.4.1 --- End-to-end streaming --- p.45Chapter 3.4.2 --- Application-layer multicast --- p.50Chapter 3.4.3 --- Experiments in real network --- p.54Chapter 3.5 --- Summary and Future Work --- p.57Chapter 4 --- DDS: Distributed Dynamic Streaming --- p.59Chapter 4.1 --- Motivation --- p.59Chapter 4.2 --- Distributed Dynamic Streaming --- p.61Chapter 4.2.1 --- DDS overlay construction --- p.62Chapter 4.2.2 --- DDS streaming --- p.64Chapter 4.3 --- Performance Analysis in Dynamic User Environment --- p.66Chapter 4.3.1 --- Basic definition and user model --- p.67Chapter 4.3.2 --- Data outage in tree topology --- p.68Chapter 4.3.3 --- Data outage in DDS --- p.70Chapter 4.4 --- Performance Evaluation --- p.73Chapter 4.4.1 --- Simulation setup --- p.73Chapter 4.4.2 --- Simulation results --- p.74Chapter 4.5 --- Summary and Future Work --- p.75Chapter 5 --- Concluding Remarks --- p.76Bibliography --- p.7

Exploring the design space of cooperative streaming multicast

Video streaming over the Internet is rapidly rising in popularity, but the availability and quality of video content is currently limited by the high bandwidth costs and infrastructure needs of server-based solutions. Recently, however, cooperative end-system multicast (CEM) has emerged as a promising paradigm for content distribution in the Internet, because the bandwidth overhead of disseminating content is shared among the participants of the CEM overlay network. In this thesis, we identify the dimensions in the design space of CEMs, explore the design space, and seek to understand the inherent tradeoffs of different design choices. In the first part of the thesis, we study the control mechanisms for CEM overlay maintenance. We demonstrate that the control task of neighbor acquisition in CEMs can be factored out into a separate control overlay that provides a single primitive: a configurable anycast for peer selection. The separation of control from data overlay avoids the efficiency tradeoffs that afflict some of the current systems. The anycast primitive can be used to build and maintain different data overlay organizations like single-tree, multi-tree, mesh-based, and hybrids, by expressing appropriate policies. We built SAAR, a reusable, shared control overlay for CEMs, that efficiently implements this anycast primitive, and thereby, efficiently serves the control needs for CEMs. In the second part of the thesis, we focus on techniques for data dissemination. We built a common framework in which different CEM data delivery techniques can be faithfully compared. A systematic empirical comparison of CEM design choices demonstrates that there is no single approach that is best in all scenarios. In fact, our results suggest that every CEM protocol is inherently limited in certain aspects of its performance. We distill our observations into a novel model that explains the inherent tradeoffs of CEM design choices and provides bounds on the practical performance limits of any future CEM protocol. In particular, the model asserts that no CEM design can simultaneously achieve all three of low overhead, low lag, and high streaming quality

Session Management in Multicast

As a new network technique to efficiently distribute information from a small number of senders to large numbers of receivers, multicast encounters many problems in scalability, membership management, security, etc. These problems hinder the deployment of multicast technology in commercial applications. To overcome these problems, a more general solution for multicast technology is needed. In this paper, after studying current multicast technologies, we summarized the technical requirements for multicast, including data delivery, scalability, security, group management, reliability, and deployment. In order to understand and meet the requirements, we define a life cycle model that most multicast sessions should follow. According to the requirements and the life cycle model, we propose and design a general solution that can control each phase of a session and satisfy most requirements for multicast technology. This general solution has three parts: hierarchical topology auto-configuration algorithm, Session Management Mechanism, and techniques supporting different multicast protocols. To verify the feasibility of our solution and compare its performance with other multicast techniques, we simulate our solution and compare it with PIM-SM and ESM

Security and Privacy Issues in Wireless Mesh Networks: A Survey

This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio

A one hop overlay system for Mobile Ad Hoc Networks

Peer-to-Peer (P2P) overlays were initially proposed for use with wired networks. However, the very rapid proliferation of wireless communication technology has prompted a need for adoption of P2P systems in mobile networks too. There are many common characteristics between P2P overlay networks and Mobile Ad-hoc Networks (MANET). Self-organization, decentralization, a dynamic nature and changing topology are the most commonly shared features. Furthermore, when used together, the two approaches complement each other. P2P overlays provide data storage/retrieval functionality and MANET provides wireless connectivity between clients without depending on any pre-existing infrastructure. P2P overlay networks can be deployed over MANET to address content discovery issues. However, previous research has shown that deploying P2P systems straight over MANET does not exhibit satisfactory performance. Bandwidth limitation, limited resources and node mobility are some of the key constraints. This thesis proposes a novel approach, OneHopOverlay4MANET, to exploit the synergies between MANET and P2P overlays through cross-layering. It combines Distributed Hash Table (DHT) based structured P2P overlays with MANET underlay routing protocols to achieve one logical hop between any pair of overlay nodes. OneHopOverlay4MANET constructs a cross-layer channel to permit direct exchange of routing information between the Application layer, where the overlay operates, and the MANET underlay layer. Consequently, underlay routing information can be shared and used by the overlay. Thus, OneHopOverlay4MANET reduces the typical management traffic when deploying traditional P2P systems over MANET. Moreover, as a result of building one hop overlay, OneHopOverlay4MANET can eliminate the mismatching issue between overlay and underlay and hence resolve key lookups in a short time, enhancing the performance of the overlay. v In this thesis, we present OneHopOverlay4MANET and evaluate its performance when combined with different underlay routing protocols. OneHopOverlay4MANET has been combined with two proactive underlays (OLSR and BATMAN) and with three reactive underlay routing protocols (DSR, AODV and DYMO). In addition, the performance of the proposed system over OLSR has been compared to two recent structured P2P over MANET systems (MA-SP2P and E-SP2P) that adopted OLSR as the routing protocol. The results show that better performance can be achieved using OneHopOverlay4MANET