Publications
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2009
Overhead and Performance Study of the General Internet Signaling Transport (GIST) Protocol ,
Christian Dickmann , Xiaoming Fu , Hannes Tschofenig , Henning Schulzrinne and Dieter Hogrefe, ACM/IEEE Transactions on Networking (to appear),
April 2009.
Read abstract
The General Internet Signaling Transport (GIST) protocol is currently being developed as the base protocol component in the IETF Next Steps In Signaling (NSIS) protocol stack to support a variety of signaling applications. We present our study on the protocol overhead and performance aspects of GIST. We quantify network-layer protocol overhead and observe the effects of enhanced modularity and security in GIST. We developed a first open source GIST implementation at the University of Goettingen, and study its performance in a Linux testbed. A GIST node serving 45,000 signaling sessions is found to consume average only 1.1 ms for processing a signaling message and 2.4 KB of memory for managing a session. Individual routines in the GIST code are instrumented to obtain a detailed profile of their contributions to the overall system processing. Important factors in determining performance, such as the number of sessions, state management, refresh frequency, timer management and signaling message size are further discussed. We investigate several mechanisms to improve GIST performance so that it is comparable to an RSVP implementation.
PDF [210.7 kB]
Routing and Scheduling for WiMAX Mesh Networks ,
Xiaoming Fu , Jianhua He, Jie Xiang, Yan Zhang and Zuoyin Tang, in: Y. Zhang (ed.), WiMAX Network Planning and Optimization, 320 pages,
Auerbach Publications, Taylor&Francis Group, USA, ISBN 1420066625, February 2009.
2008
Diameter WebAuth: An AAA-based Identity Management Framework for Web Applications ,
Xiaoming Fu , Niklas Neumann , The 51th Annual IEEE Global Telecommunications Conference (GLOBECOM 2008), Computer and Communications Network Security Symposium, New Orleans, LA, USA,
IEEE, December 2008.
Read abstract
With an increasing number of personalized information and services offered on the Internet, especially the World WideWeb, effective identity management solutions are demanded by application providers. Instead of a web-based stand-alone approach, we extend existing network-based AAA mechanisms to be usable for identity management by web applications. Our proposal, Diameter WebAuth, allows to seamlessly integrate web-based services into a Diameter infrastructure for authentication, authorization, credit-control and identity management purposes. Diameter WebAuth offers comparable features to web-based identity management solutions, benefits from the maturity and wide deployment of the Diameter protocol, and takes advantage of existing AAA setups.
PDF [253.4 kB]
Performance Study of the NSIS QoS-NSLP Protocol ,
Mayutan Arumaithurai , Xiaoming Fu , Bernd Schloer , Hannes Tschofenig , The 51th Annual IEEE Global Telecommunications Conference (GLOBECOM 2008), Next Generation Networks, Protocols, and Services Symposium, New Orleans, LA, USA,
IEEE, December 2008.
Read abstract
This paper presents an evaluation of the Quality of Service Signalling Layer Protocol (QoS-NSLP) of the NSIS (Next Steps In Signalling) protocol suite. The QoS-NSLP in combination with the NSIS Transport Layer Protocol (NTLP) is proposed by the Internet Engineering Task Force (IETF) as an alternative to the Resource reSerVation Protocol (RSVP). We describe our implementations of the software architecture, both on a network simulator and on a Linux implementation. Both implementations are used in a complimentary manner to illustrate the performance of the QoS-NSLP protocol. The results show the performance of QoS-NSLP with respect to resource consumption, packet processing time, session set up time, refresh interval and protocol overhead. Furthermore, we analyse the protocol performance during route change scenarios.
PDF [328.7 kB]
A Cross-Layer Approach for Improving TCP Performance in Mobile Environments ,
Xiaoming Fu , Deguang Le , Dieter Hogrefe, Wireless Personal Communications, special issue on "Resource and Mobility Management and Cross-Layer Design for the Support of Multimedia Services in Heterogeneous Emerging Wireless Networks",
Springer Verlag, October 2008.
Read abstract
Network-layer mobility protocols have been developed to keep continuous connectivity for mobile hosts while transparent to the higher layers. However, Due to its distinct characteristics of different from traditional TCP/IP environment, mobility poses substantial impacts on TCP performance in mobile environments.
This paper proposes a new cross-layer approach, by introducing a mobility detection element in the network layer which interacts with the transport layer to optimize TCP operations. As changes are only made to the endpoints, this approach preserves the end-to-end semantics of TCP. Different from most exiting works, which utilize either transport or network layer alone without much cross-layer cooperation, our approach allows the use of mobility information in TCP. We analytically compare this approach against existing approaches and show that our approach outperforms prior approaches in terms of effective data resumption time. Through performance simulations, our approach demonstrates that it can effectively improve TCP performance in Mobile IPv6-based mobile environments.
PDF [288.3 kB]
Evaluating the benefits of introducing PMIPv6 for localized mobility management ,
Xiaoming Fu , Jun Lei , in the Proceedings of International Wireless Communications and Mobile Computing Conference 2008 (IWCMC 2008), Crete, Greece,
IEEE, August 2008.
Read abstract
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]
Applicability Statement of NSIS Protocols in Mobile Environments ,
Xiaoming Fu , Hannes Tschofenig , Takako Sanda, Seong-Ho Jeong and Jukka Manner, Internet Engineering Task Force, Internet draft (draft-ietf-nsis-applicability-mobility-signaling-10), work in progress, Next Steps in Signaling (NSIS) Working Group,
April 2008.
Read abstract
Mobility of an IP-based node affects routing paths, and as a result, can have a significant effect on the protocol operation and state management. This draft discusses the effects mobility can cause to the NSIS protocol suite, and how the protocols operate in different scenarios, with mobility management protocols.
TXT [85.8 kB]
A Network Virtualisation Concept Based on Ambient Networks SATO System ,
Xiaoming Fu , Martin Stiemerling , and Marcus Brunner, 1. GI/ITG Fachgespraech Virtualisierung, Paderborn, Germany, pages 33 - 36,
February 2008.
Read abstract
Network virtualization can be one way of fixing the shortcomings of todays Internet but also open the venue for new, unforeseen applications. In this extended abstract, we present a novel approach for network virtualisation based on the Service-Aware Transport Overlay (SATO) concept of Ambient Networks. SATOs introduce on-demand overlay creation and new interfaces to ease applications to use overlays.
PDF [295.8 kB]
Reports of Advanced Topics in Computer Networking and Mobile Communications (Summer 2004 - Winter 2006/2007) ,
Xiaoming Fu , and Dieter Hogrefe (editors), Technical Report No. IFI-TB-2008-01, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, February 2008.
Read abstract
This technical report includes the final reports written by students for seminars from summer semester 2004 to winter semester 2006/07 on advanced topics in computer networking/Internet research and mobile communications, including mobile, ad hoc, sensor networks and location-based systems; wireless networks, security and performance optimization issues; mobile applications and mobile devices; overlay, peer-to-peer and application layer multicast, as well as delay tolerant networks.
PDF [8327.7 kB]
GIST State Machine ,
Xiaoming Fu , Hannes Tschofenig , Tseno Tsenov, Cedric Aoun, and Elwyn Davies, Internet Engineering Task Force, Internet draft (draft-ietf-nsis-ntlp-statemachine-05), work in progress, Next Steps in Signaling (NSIS) Working Group,
February 2008.
Read abstract
This document describes the state machines for the General Internet Signaling Transport (GIST). The states of GIST nodes for a given flow and their transitions are presented in order to illustrate how GIST may be implemented.
PDF [633.8 kB]
General Internet Signaling Transport (GIST) over SCTP ,
Christian Dickmann , Xiaoming Fu , and Jon Crowcroft, Internet Engineering Task Force, Next Steps in Signaling (NSIS) Working Group,
February 2008.
Read abstract
The General Internet Signaling Transport (GIST) protocol currently uses TCP or TLS over TCP for connection mode operation. This document describes the usage of GIST over the Stream Control Transmission Protocol (SCTP). The use of SCTP can take the advantage of features provided by SCTP, namely streaming-based transport, support of multiple streams to avoid head of line blocking, and the support of multi-homing to provide network level fault tolerance. Additionally, the support for the Partial Reliability Extension of SCTP is discussed.
TXT [22.0 kB]
Probe-aided MulTCP: An Aggregate Congestion Control Mechanism ,
Xiaoming Fu , Fang-Chun Kuo , ACM SIGCOMM Computer Communication Review, Vol. 38, No. 1, Pages 19-28,
ACM, ISSN 0146-4833, January 2008.
Read abstract
An aggregate congestion control mechanism, namely Probe-Aided MulTCP (PA-MulTCP), is proposed in this paper. It is based on MulTCP, a proposal for enabling an aggregate to emulate the behavior of multiple concurrent TCP connections. The objective of PA-MulTCP is to ensure the fair sharing of the bottleneck bandwidth between the aggregate and other TCP or TCP-friendly flows while keeping lightweightness and responsiveness. Unlike MulTCP, there are two congestion window loops in PA-MulTCP, namely the probe window loop and the adjusting window loop. The probe window loop constantly probes the congestion situation and the adjusting window loop dynamically adjusts the congestion window size for the arriving and leaving flows within the aggregate. Our simulations demonstrate that PA-MulTCP is more stable and fairer than MulTCP over a wide range of the weight N in steady conditions as well as in varying congestion conditions. PA-MulTCP is responsive to flow-arriving/leaving and thus reduces the latency of short-lived transfers. Furthermore, PA-MulTCP is lightweight, since it enjoys above advantages at the cost of only an extra probe window loop, which has a marginal influence on the implementation complexity. Finally, the design of PA-MulTCP decouples the congestion management from the other functionalities in the aggregate flow management. As a result, PA-MulTCP could be potentially applied to a wider range of scenarios, e.g. wireless TCP proxies, edge-to-edge overlays, QoS provisioning and mass data transport.
PDF [758.8 kB]
2007
Optimized FMIPv6 Using IEEE802.21 MIH Services in Vehicular Networks ,
Xiaoming Fu , Qazi Mussabbir, Wenbing Yao and Zeyun Niu, IEEE Transactions on Vehicular Technology, Special Issue on Vehicular Communications Networks, Volume 56, Issue 6, Pages 3397 - 3407,
IEEE, ISSN 0018-9545, November 2007.
Read abstract
In this paper, we optimize the handover procedure in Fast Handover for Mobile IPv6 (FMIPv6) protocol by using IEEE 802.21 Media Independent Handover (MIH) services. FMIPv6 is used to enhance the performance of handovers in Mobile IPv6 (MIPv6) and its basic extension for Network Mobility (NEMO), the fundamental mobility management protocols used in vehicular networks. With the aid of the lower three layers information of the mobile node/router (MN/MR) and the neighboring access networks, we tackle the radio access discovery and candidate Access Router (AR) discovery issues of FMIPv6. We introduce an Information Element Container to store static and dynamic Layer 2 (L2) and Layer 3 (L3) information of neighboring access networks, and propose to use a special cache maintained by the MN/MR to reduce the anticipation time in FMIPv6, thus increasing the probability of the predictive mode of the FMIPv6 operation. Furthermore, we propose a cross-layer mechanism for making intelligent handover decisions in FMIPv6. Lower layer information of the available links obtained by MIH services as well as the higher layer information such as quality of service parameter requirements of the applications are used by a Policy Engine (PE) to make intelligent handover decision. We will show through analysis and simulations of the signaling procedure that the overall expected handover (both L2 and L3) latency in FMIPv6 can be significantly reduced in the proposed mechanism.
PDF [214.6 kB]
A New Decentralized Mobility Management Service Architecture for IPv6-based Networks ,
Xiaoming Fu , Deguang Le , Jun Lei , 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.
Read abstract
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 NSIS-based Approach for Firewall Traversal in Mobile IPv6 Networks ,
Xiaoming Fu , Niklas Steinleitner , Hannes Tschofenig , Dieter Hogrefe, and Thomas Schreck, Third Annual International Wireless Internet Conference (WICON 2007), Austin, Texas, USA,
ACM Press, October 2007.
Read abstract
Firewalls have been successfully deployed in todays network infrastructure in various environments and will also be used in IPv6 networks. However, most of the current firewalls do not support Mobile IPv6, the best known standardized solution for mobility support in IPv6. As a result, Mobile IPv6 traffic will be most likely dropped when used without an appropriate firewall traversal solution.
This paper describes the problems and impacts of having firewalls in Mobile IPv6 environments and presents a firewall traversal solution based on the IETFs Next Steps In Signaling framework to address these issues. Compared with other candidates such as STUN, TURN, ICE, ALG, MIDCOM
and COPS, this approach does not rely on specific firewall placements and can be applied in various operational modes without additional introducing entities. In this paper we also explore security aspects since they are typically difficult to handle.
PDF [372.2 kB]
An Experimental Analysis of Joost Peer-to-Peer VoD Service ,
Xiaoming Fu , Jun Lei , Lei Shi , Technical Report No. IFI-TB-2007-03, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, October 2007.
Read abstract
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]
An overview of digital TV standards in China ,
Xiaoming Fu , Xiaodong Yang , Roland A. Burger, Giovanni Iacovoni, Cliff Reader, and Wang Hui, Proceedings of ChinaCom 2007, Shanghai, China, Special Session on Digital Broadcasting and Mobile Convergence,
IEEE, August 2007.
Read abstract
This paper presents an updated overview of the different proposed standards on the market for mobile TV in China as of June 2007 and analyzes the different trade-offs, strengths and weaknesses. Furthermore the used video codecs are compared with special emphasis on the usage in mobile TV in China.
PDF [4370.5 kB]
Comparative Studies on Authentication and Key Exchange Methods for 802.11 Wireless LAN ,
Xiaoming Fu , Jun Lei , Dieter Hogrefe, Jianrong Tan, Computers & Security, Volume 26, Issue 5, Pages 401-409,
Elsevier, ISSN 0167-4048, August 2007.
Read abstract
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 ,
Xiaoming Fu , Jun Lei , Technical Report No. IFI-TB-2007-02, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, June 2007.
Read abstract
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]
Probe-Aided MulTCP: An Aggregate Congestion Control Mechanism ,
Xiaoming Fu , Fang-Chun Kuo , Technical Report No. IFI-TB-2007-01, Institute of Computer Science, University of Goettingen, Goettingen, Germany,
ISSN 1611-1044, April 2007.
Read abstract
A number of new application scenarios, e.g. mobile/wireless TCP proxies, edge to edge overlays, QoS provisioning and mass data transport, are calling for aggregate flow management. In this paper we show that applying a single flowshare to an aggregate flow will result in unfairness in the bandwidth sharing between the aggregate traffic and the background flows sharing the same bottleneck. To overcome this problem, we propose an aggregate congestion control mechanism, namely probe-aided MulTCP, which dynamically adjusts the congestion window loop to support multiple flowshares for an aggregate. The probe-aided MulTCP differs from existing works, such as MPAT, CP, MulTCP, in the following aspects. Firstly, our simulations show that against the traditional MulTCP the probe-aided MulTCP could maintain relatively stable, smooth and fair performance over a wide range of weight N in steady conditions as well as in varied congestion conditions. Secondly, an adjusting window loop is introduced to constantly probe the congestion situation and dynamically adjust the congestion window size for the newly arriving and leaving flows within the aggregate. This integration of congestion information improves the startup performance for new arriving flows, especially for short-lived ones. Thus, the probe-aided MulTCP is lightweight since only one extra probe window loop is used. Our extensive simulation studies show that with the probe-aided MulTCP, the improved performance and fairness will overweight the complexity caused by two congestion window loops.
PDF [665.8 kB]
ENABLE QoS Services for Large Operational IP Mobility Networks ,
Xiaoming Fu , Ivano Guardini, Presented at the 1st OpenNet Workshop, Brussels, Belgium,
March 2007.
E2T: End-to-End Tunnelling Extension to Mobile IPv6 ,
Xiaoming Fu , Dieter Hogrefe , Deguang Le , and Xiaoyuan Gu, in Proceedings of the 4th IEEE Consumer Communications and Networking Conference (CCNC 2007), Las Vegas, Nevada, USA,
IEEE Communications Society, January 2007.
Read abstract
In the standard Mobile IPv6 (MIPv6), the bidirectional tunnelling through the home agent or the route optimization show inefficiency in per-packet routing, especially when both communicating endpoints are mobile. To be scalable and compatible, mobile devices packets should be routed efficiently with minimal changes to the network infrastructure. However, the current solutions do not provide any means for the end systems to perform optimized packet routing during the operation of the mobile devices. In this paper, we present an end-to-end tunnelling extension to MIPv6 (E2T) for mobile routing packets, which reduces the per-packet routing cost for the communications of mobile devices through the lower packet routing overhead. Besides, our approach requires little change to MIPv6, but allows the more efficient routing behavior with the shorter end-to-end transmission latency between communicating endpoints. The simulation results show our approach is suitable for real-time multimedia applications.
PDF [357.5 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , 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.
Read abstract
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]
2006
MobiArch'06 - Proceedings of the First ACM/IEEE International Workshop on Mobility in the Evolving Internet Architecture ,
Xiaoming Fu , Katherine Guo, and Jon Crowcroft (editors), San Francisco, CA, USA,
ACM Press, ISBN 1-59593-566-5, December 2006.
Beyond QoS Signaling: a Generic IP Signaling Framework ,
Xiaoming Fu , Hannes Tschofenig , and Dieter Hogrefe, Computer Networks, Volume 50, Issue 17, pages 3416-3433,
Elsevier, December 2006.
Read abstract
This paper describes the design principles and an introduction of a framework and protocols for generic IP signaling, namely the Cross-Application Signaling Protocol (CASP) and its signaling applications. While reusing certain features of the existing RSVP protocol, CASP overcomes its shortcomings and may be deployed as a replacement technology to provide simpler, mobility-supported, more extensible and more secure signaling services in IP based networks. This paper discusses challenges of todays IP signaling protocols and addresses fundamentals and key aspects of CASP and its current signaling applications. In addition, a comparison with previous signaling protocol proposals and an outlook of future work in this area are also given.
PDF [602.3 kB]
From Resource Reservation to Extensible IP Signaling ,
Xiaoming Fu , Habilitation Thesis, Mathematische Fakultaet, Universitaet Goettingen, Goettingen, Germany, 146 pages,
October 2006.
Dynamic Mesh-based overlay Multicast Protocol (DMMP) ,
Xiaoming Fu , Dieter Hogrefe , Jun Lei , Internet Research Task Force, Internet draft (draft-lei-samrg-dmmp-01), work in progress, Scalable Adaptive Multicast (SAM) Research Group,
October 2006.
Read abstract
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]
Securing the Next Steps in Signalling (NSIS) Protocol Suite ,
Xiaoming Fu , Hannes Tschofenig , International Journal of Internet Protocol Technology, Volume 1, No. 4, pages 271-282,
InderScience Publishers, ISSN 1743-8209, August 2006.
Read abstract
The Next Steps In Signalling (NSIS) protocol suite represents an extensible framework for enabling various signalling applications over IP-based networks. The framework consists of two layers that need different types of security protection; the lower layer mainly deals with the discovery of adjacent peers and establishment of channel security to protect the delivery of signalling messages between two peers, while the upper layer provides the signalling application specific functionalities. Different security properties are required at the two layers with stronger authorisation functionality at the signalling application layer. In this paper we examine how various security vulnerabilities can be utilised by an adversary, including eavesdropping, Man-In-The-Middle (MITM) attacks, fraud and Denial of Service (DoS) attacks. Moreover, we describe how to protect against a number of selected security threats and highlight some security challenges that require further research.
PDF [431.5 kB]
Implementation and Performance Study of a New NAT/Firewall Signaling Protocol ,
Xiaoming Fu , Henning Peters , Niklas Steinleitner , Hannes Tschofenig , in Proceedings of the 26th International Conference on Distributed Computing Systems-Workshops (ICDCSW 2006), the 5th International Workshop on Assurance in Distributed Systems and Networks (ADSN2006), Lisboa, Portugal,
IEEE Computer Society, ISBN 0-7695-2541-5, July 2006.
Read abstract
The NAT/Firewall NSIS Signaling Layer Protocol (NAT/FW NSLP) is a path-coupled signaling protocol for explicit Network Address Translator and firewall configuration within an extensible IP signaling framework currently being developed by the IETF Next Steps in Signaling (NSIS) working group. This new protocol allows end hosts to signal along a path to configure NATs and firewalls according to the data flow needs. In this paper we present a first open source implementation and performance evaluation of the NAT/FW NSLP protocol. The implementation utilizes a generic state machine template and can automatically generate source code for message handling classes. The performance study shows that our implementation scales well and is able to support firewall signaling for up to tens of thousands of flows in parallel even in a low-end PC testbed environment. The overall performance bottleneck is found to lie in the utilized firewall implementation, not depending on the NAT/FW NSLP implementation.
PDF [394.6 kB]
DMMP: A New Dynamic Mesh-based Overlay Multicast Protocol Framework ,
Xiaoming Fu , Jun Lei , Technical Report No. IFI-TB-2006-05, Institute of Computer Science, University of Goettingen, Germany,
ISSN 1611-1044, July 2006.
Read abstract
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]
Modelling Soft-State Protocols with SDL ,
Xiaoming Fu , Dieter Hogrefe , IEE Proceedings Communications,
ISSN 1350-2425, Volume 153, Issue 3, pages 365-375, June 2006.
GONE: an Infrastructure Overlay for Resilient, DoS-Limiting Networking ,
Xiaoming Fu , and Jon Crowcroft, Proceedings of the 16th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV 2006), Newport, Rhode Island, USA,
ACM, May 2006.
Read abstract
With today's penetration in volume and variety of information flowing across the Internet, data and services are experiencing various issues with the TCP/IP infrastructure, most notably availability, reliability and mobility. Therefore, a critical infrastructure is highly desireable, in particular for multimedia streaming applications. So far the proposed approaches have focused on applying application-layer routing and path monitoring for reliability and on enforcing stateful packet filters in hosts or network to protect against Denial of Service (DoS) attacks. Each of them solves its own aspect of the problem, trading scalability for availability and reliability among a relatively small set of nodes, yet there is no single overall solution available wh
