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An Experimental Analysis of Joost Peer-to-Peer VoD Service,
Jun Lei, Lei Shi, Xiaoming Fu, Peer-to-Peer Networking and Applications, Volume 3, Number 4, Pages 351-362,
Springer Verlag, ISSN 1936-6442, December 2010.
Despite strong interest in peer-to-peer (P2P) Video-on-Demand (VoD) services, existing studies mostly focus on peer-to-peer or overlay protocol design based on simulations under various topological constraints. We believe experimental studies on a real-life P2P VoD system will provide valuable information to ISPs, network administrators, and content owners. In this paper we present a comprehensive analytical and experimental study on Joost, one of the first commercial P2P VoD systems used for distributing various forms of video over the Internet. Our extensive experiments prove that Joost is a server-assisted peer-to-peer VoD system. With several envisioned typical scenarios we have further investigated the peer management in terms of time pattern, bandwidth consumption and locality considerations. Our major findings include: (1) the current Joost system is capable of providing high-quality VoD service through the use of an overlay network deployed with a set of centralized content servers; (2) inter-continental links are often used regardless of the number of local users, which may pose a high burden on the network providers; (3) easily reachable, high-capacity nodes are selected as main relaying nodes, similar to super nodes in Skype, to facilitate the traversal of symmetric NATs and firewalls. We also provide insights on the potential ways to construct more efficient P2P VoD systems (e.g. considering topological locality-awareness, using adaptive/layered video).
PDF.pdf [601.9 kB]
D-MORE: Dynamic Mesh-based Overlay Peer-to-Peer Infrastructure,
Jun Lei, Xiaoming Fu, and Dieter Hogrefe, Computer Communications: The International Journal for the Computer and Telecommunications Industry, Volume 33, Issue 10, Pages 1191-1201,
Elsevier, June 2010.
Traditionally, Internet Service Providers (ISPs) have to interconnect with content providers to provide network services to customers. The current business model that connectivity and bandwidth become commodities has motivated ISPs to distribute content and other application-specific services directly to their customers. Hence, it is desirable for ISPs to economize existing infrastructure to support a variety of applications and services.
We propose a dynamic mesh-based overlay peer-to-peer infrastructure (D-MORE) and illustrate its example usage case among other potentials. We describe several key techniques, namely capacity classification, locality-awareness and incentive mechanisms for construction of the tiered infrastructure. Through extensive simulations, we show D-MORE scales well with an increasing number of hosts, in terms of control overhead and link stress, for supporting media distribution services. We propose further improvements to enhance the D-MORE performance, which brings up to 35% network resource savings and up to 200% control overhead reduction in our simulations.
PDF [586.3 kB]
Interest-based Peer-to-Peer Group Management,
Jun Lei, Xiaoming Fu, Second IEEE/ACM International Workshop on Future Multimedia Networking (FMN 2009), Coimbra, Portugal,
Springer LNCS, June 2009.
Peer-to-Peer systems become popular applications but suffer from insufficient resource availability which is caused by free-riders and inefficient lookup algorithms. To address the first cause, a number of recent works have focused on providing appropriate incentive mechanisms to encourage participants to contribute their resources to the P2P systems. To improve the lookup efficiency, locality-aware peer management has been introduced into the research community. However, existing proposals attempt to optimize the service performance during the data transmission period mostly after performing the neighboring lookup, which cannot address the fundamental concern of reducing lookup traffic. Besides, existing implementations select available contributors among random neighbors suggested by a specific server. Therefore, this paper proposes interest-based peer-to-peer management (IPM) protocol to facilitate the peering lookup. Our design philosophy differs from existing work that IPM is a client-only approach and can be represented as either an alternative or a complementary to the current proposals. With additional locality-awareness considerations, IPM can reduce the lookup overhead while optimizing the P2P traffic performance. The simulation results essentially state that IPM can largely improve the efficiency and reliability of P2P media distribution systems, for instance, reduces control overhead by 50% on average and reduces average packet loss rate up to 34.7%.
PDF [234.0 kB]
I-PMIP: An Inter-Domain Mobility Extension for Proxy Mobile IP,
Niklas Neumann, Jun Lei, Xiaoming Fu, Gong Zhang, in the Proceedings of 5th International Wireless Communications and Mobile Computing Conference (IWCMC 2009), Leipzip, Germany,
ACM Digital Library, June 2009.
Proxy Mobile IP (PMIP) provides a solution for network-based localized mobility management which in contrast to host-based mobility solutions, like Mobile IP (MIP), does not require changes to the end-hosts and avoids tunneling overhead between the mobile node and it's network access point. Within a PMIP-enabled mobility domain, the mobile node is able to maintain the same IP address when it moves. However, if the mobile node leaves this domain the mobility support breaks. This paper proposes an extension to PMIP, called I-PMIP which allows to interconnect multiple PMIP-enabled mobility domains to provide continuous mobility support for a mobile user. I-PMIP is based on an architecture that can provide a mobile node with an anchor point that is placed very close towards the mobile. Numerical analysis show that the approach is comparable to other approaches that provide inter-domain mobility.
PDF [231.4 kB]
A Unified Security Backplane for Trust and Reputation Systems in Decentralized Networks,
Florian Tegeler, Jun Lei, and Xiaoming Fu, IEEE INFOCOM 2009 Student Workshop,
Trust and Reputation (TR) systems are a recently proposed means to address free-rider issues in decentralized networks such as P2P, DTNs, and wireless mesh networks. Basically, TR systems identify malicious node behaviors by observation and direct interaction experience. However, these systems often lack a security framework to prevent a variety of attacks, such as identity spoofing or capturing and false reports on nodes behavior. We present a security backplane preventing such attacks by providing authentication, non-repudiation and other security services without predetermining the exact TR algorithm on node interaction selection and the metrics on the evaluation of nodes. Utilizing this security framework, multiple proposed algorithms such as Scrubber, Eigentrust, CONFIDENT or pricing systems can be implemented with increased and flexible security properties.
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Evaluating the benefits of introducing PMIPv6 for localized mobility management,
Jun Lei, and Xiaoming Fu, in the Proceedings of International Wireless Communications and Mobile Computing Conference 2008 (IWCMC 2008), Crete, Greece, Pages 74-80,
IEEE, August 2008.
Abstract—Since recent years, it has been recognized that using global mobility protocol for managing localized mobility causes a number of problems, such as a long registration delay. To overcome these problems, Proxy Mobile IPv6 is proposed, which can avoid tunneling overhead over the air and support for hosts without an involvement in the mobility management. In this paper, we first discuss the recent localized mobility proposals and explore three major benefits that PMIPv6 can bring. In particular, we evaluate two aspects of the handover performance through a simple mathematical model for Fast Handovers for MIPv6, Hierarchical MIPv6, Fast handovers for HMIPv6 and PMIPv6. These analytical studies show that PMIPv6 may cause high handover latency if the local mobility anchor is located far from the current mobility access gateway. Therefore, some enhancements for PMIPv6 are suggested to further reduce the handover latency. The analysis ascertains that F-PMIPv6 is a promising mobility scheme to efficiently manage the localized mobility.
PDF [206.1 kB]
D-MORE: Dynamic Mesh-based Overlay Peer-to-Peer Infrastructure,
Jun Lei, Xiaoming Fu, and Dieter Hogrefe, Technical Report No. IFI-TB-2008-02, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, August 2008.
Traditionally, Internet Service Providers (ISPs) have
to interconnect with content providers to provide network services
to customers. Current business model that connectivity
and bandwidth become commodities has motivated ISPs to
distribute content and other application-specific services to their
customers using their own infrastructure. It is desirable for
ISPs to economize existing infrastructure to support a variety
of applications and services.
We propose a dynamic mesh-based overlay peer-to-peer infrastructure
and illustrate its two examples usage cases among other
potentials. We describe several key techniques, namely capacity
classification, locality-awareness and incentive mechanisms for
construction of the tiered infrastructure. Through extensive
simulations, we show D-MORE scales well with an increasing
number of hosts, in terms of control overhead, link stress and
data path length, for supporting media distribution services.
We propose further improvements to enhance the D-MORE
performance, which brings up to 35% network resource savings
and up to 200% control overhead reduction in our simulations.
PDF [539.6 kB]
Media Distribution using Overlay Multicast and Peer-to-Peer Technologies,
Jun Lei, PhD thesis, Faculty of Mathematics, University of Goettingen, Germany,
A New Decentralized Mobility Management Service Architecture for IPv6-based Networks,
Deguang Le, Jun Lei, and Xiaoming Fu, in Proceedings of the 3rd ACM International Workshop on Wireless Multimedia Networking and Performance Modeling (WMuNeP'07), in conjunction with the 10th ACM/IEEE International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM'07), Chania, Crete Island, Greece,
ACM Press, New York, NY, USA, October 2007.
In Mobile IPv6, the home network - through a designated home agent - is responsible for distributing all traffic from/to the mobile node in the default bidirectional tunneling mode, when the mobile node is connected to a foreign network. This approach not only lacks sufficient scalability and efficiency of delivery, but also poses a heavy burden on the home network and the global Internet. In this paper we propose a new decentralized mobility management service (DMMS) architecture to address this issue. The idea is to employ a local mobility agent in each access network, which handles node mobility based on local movement information, so that the ongoing communication can be maintained efficiently and scalable without relying on centralized traffic distributing entities.
PDF [297.9 kB]
An Experimental Analysis of Joost Peer-to-Peer VoD Service,
Jun Lei, Lei Shi, and Xiaoming Fu, Technical Report No. IFI-TB-2007-03, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, October 2007.
Most of the current Video-on-Demand (VoD) systems rely on content distribution networks or some local streaming proxies. While these traditional systems offer a means for media delivery and streaming, they also pose a significant performance challenge in terms of scalability and service delay as the number of clients increases. To solve this issue, peer-to-peer (P2P) technologies have been applied to support the VoD systems. Joost is one of such systems for distributing TV shows or other forms of video over the Internet. However, like Skype in its early stage, the mechanisms behind Joost are still unrevealed.
The main purpose of this paper is therefore to study the underlying Joost architecture and its key components, and analyze its media streaming behaviors and peer management mechanisms through close investigations on Joost network traffic. With three envisioned typical scenarios we have further studied the Joost performance in terms of locality awareness, bandwidth capacity and VoD functionalities. Based on extensive experiments, we infer that Joost is a server-assisted peer-to-peer VoD system. It mainly relies on a set of delicate infrastructure nodes (e.g. content servers) for video distribution. To our best knowledge, this paper is the first analytical and performance study on commercial P2P VoD services.
PDF [436.4 kB]
Comparative Studies on Authentication and Key Exchange Methods for 802.11 Wireless LAN,
Jun Lei, Xiaoming Fu, Dieter Hogrefe, and Jianrong Tan, Computers & Security, Volume 26, Issue 5, Pages 401-409,
Elsevier, ISSN 0167-4048, August 2007.
IEEE 802.11 wireless LAN has become one of the hot topics on the design and development of network access technologies. In particular, its authentication and key exchange (AKE) aspects, which form a vital building block for modern security mechanisms, deserve further investigation. In this paper we first identify the general requirements used for WLAN authentication and key exchange (AKE) methods, and then classify them into three levels (mandatory, recommended, and additional operational requirements). We present a review of issues and proposed solutions for AKE in 802.11 WLANs. Three types of existing methods for addressing AKE issues are identified, namely, the legacy, layered and access control-based AKE methods. Then, we compare these methods against the identified requirements. Based on the analysis, a multi-layer AKE framework is proposed, together with a set of design guidelines, which aims at a flexible, extensible and efficient security as well as easy deployment.
PDF [116.1 kB]
Evaluating the Benefits of Introducing PMIPv6 for Localized Mobility Management,
Jun Lei, and Xiaoming Fu, Technical Report No. IFI-TB-2007-02, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, June 2007.
Since recent years, it has been recognized that using global mobility protocol for managing localized mobility causes a number of problems, such as long registration delay. To overcome these problems, host-based and network-based localized mobility approaches have been proposed. Moreover, network based mobility management is more desirable since it requires no host software stack changes. Proxy Mobile IPv6 (PMIPv6) provides a solution for network-based mobility management that can avoid tunneling overhead over the air and support for hosts without an involvement in the mobility management.
We first review the localized mobility proposals and explore three major benefits that PMIPv6 can bring. In particular, we evaluate two aspects of the handover performance through a mathematical model for Fast Handovers for MIPv6 (FMIPv6), Hierarchical MIPv6 (HMIPv6), Fast handovers for HMIPv6 (F-HMIPv6) and PMIPv6. These analytical studies show that PMIPv6 may cause high handover latency if the local mobility anchor (LMA) is located far from the current mobility access gateway (MAG).
In this paper, we therefore propose an enhancement for PMIPv6, so-called fast handovers for PMIPv6 (F-PMIPv6) to further reduce the handover latency. The analysis result ascertains that F-PMIPv6 is a promising mobility scheme to efficiently manage the localized mobility.
PDF [184.3 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework,
Jun Lei, Xiaoming Fu, and Dieter Hogrefe, Proceedings of the 2007 IEEE Consumer Communications and Networking Conference - Workshop on Peer-to-Peer Multicasting (P2PM 2007), Las Vegas, Nevada, USA,
IEEE Communications Society, January 2007.
Multicasting can provide an efficient way of delivering data from a sender to a group of receivers. It has received much attention over the past decade because of an increasing demand for group communication applications such as multimedia streaming. However, native IP multicast has not become widespread largely due to its technical and operational issues. To overcome these obstacles of deployment, various application layer and overlay multicast approaches have been proposed. Compared with IP multicast, they provide a new way of handling multicast without upgrading the infrastructure in a large scale. Nevertheless, they introduce a number of challenges and are still plagued with concerns on scalability, heterogeneity and dynamic performance. In this paper we propose a new protocol framework for addressing these issues, so-called the Dynamic Mesh-based Overlay Multicast Protocol or DMMP, which intends to provide an efficient and resilient multicast support by dynamically managing an overlay core comprised of end hosts. Moreover, DMMP can be used for media streaming which is contracted by a limited resource in stream supplying entities and requires good scalability and reliability. Initial analysis shows that DMMP has the potential to efficiently deliver multicast services for large groups.
PDF [311.3 kB]
Dynamic Mesh-based overlay Multicast Protocol (DMMP),
Jun Lei, Xiaoming Fu, and Dieter Hogrefe, Internet Research Task Force, Internet draft (draft-lei-samrg-dmmp-01), work in progress, Scalable Adaptive Multicast (SAM) Research Group,
This document describes a Dynamic Mesh-based overlay Multicast Protocol (DMMP) to support multicast data delivery applications without relying on classic IP multicast, including multicast group management, overlay hierarchy establishment, multicast tree construction and data forwarding scheme from the source to a number of receivers. The DMMP framework builds on control plane functions which dynamically manage an overlay core and a multicast tree layer. The key idea is a number of end hosts self-organize into an overlay mesh, and dynamically maintain such a mesh. Based on the constructed mesh, some core-based clusters are built with capacity-aware trees inside. Then, a multicast tree consisting of DMMP-aware end hosts (and/or specific routers) is built on the top of the overlay core for the efficient delivery of the multicast data.
PDF [64.0 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework,
Jun Lei, Xiaoming Fu, and Dieter Hogrefe, Technical Report No. IFI-TB-2006-05, Institute of Computer Science, University of Goettingen, Germany,
ISSN 1611-1044, July 2006.
Multicasting provides an efficient way of delivering data from a sender to a group of receivers. It has been gained much attention over the past decade because of an increasing demand for group communication applications such as multimedia streaming. Compared with network layer multicast solutions, recent application-layer multicast and overlay multicast approaches provide a new way of handling multicast without upgrading the infrastructure in a large scale. Meanwhile, they introduce a number of challenges and are still plagued with concerns pertaining to scalability, deployment, heterogeneity and dynamic performance. In this paper we propose a new protocol framework for relieving these issues, so-called the Dynamic Mesh-based Overlay Multicast Protocol or DMMP, which intends to provide an efficient and reliable multicast support by dynamically managing an overlay core comprised of end hosts. Although more analysis and evaluation is necessary, this paper sheds light on several identified design issues with DMMP and initially analyzes its performance.
PDF [689.2 kB]
Architectural Thoughts and Requirements Considerations on Video Streaming over the Internet,
Jun Lei, Ingo Juchem, Xiaoming Fu, and Dieter Hogrefe, Technical Report No. IFI-TB-2005-06, Institute of Computer Science, University of Goettingen, Germany,
ISSN 1611-1044, November 2005.
With increasing demands of multimedia information over the Internet, video streaming has been received explosive attentions. With respect to the real-time nature of video streaming, instable bandwidth, latency, noise, packet loss, retransmission and out of order packet delivery are all problems that can affect video streaming over the Internet. However, the traditional Internet traffic is not sensitive to these problems. Based on the general video streaming architecture, we give out some considerations on design and architectural mechanisms, namely, media server, media compression, media QoS control, media distribution services, media security mechanisms and protocol stacks for video streaming. For each of these areas, we present some existing methods and implementations. Then we propose architecture via overlay multicast integrated with proxy caching to achieve efficiency, flexibility and scalability. Finally, we conclude this issue and point out the research direction.
PDF [503.1 kB]
Video Image-based Intelligent Architecture for Human Motion Capture,
Jun Lei, Dieter Hogrefe, and Jianrong Tan, ICGST International Journal on Graphics, Vision and Image Processing (GVIP), Volume 5, Issue 5, Pages 11-16,
ISSN 1687-398X, May 2005.
The study of human motion is a fascinating subject in computer vision and has been developed quite a few years. Traditional methods to realize human motion capture mainly use equipments of machinery, electromagnetic, acoustics, optics, graphics and so on. Whereas these are some defects existed in these methods e.g. expensive equipments, the place limited by sensors and localization of sport range, and it has no consistent standards because of different purposes and requirements. Most importantly, they always need a person to execute the long and sterile work for surveillance. Sometimes only by manual operation cannot accord with desires that data should be collected without redundant or unhelpful information. In view of video characters which bring about changes and new opportunities in the human motion capturing technology, this paper presents an actual architecture to automatically capture human motion by comparing video images and extracting surveillant area. Then we provide an effective method for storage. Furthermore, the functionalities of architecture are realized in GOLF sport education example.
PDF [286.2 kB]