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Showing papers presented at "Testbeds and Research Infrastructures for the DEvelopment of NeTworks and COMmunities in 2009"


Proceedings ArticleDOI
06 Apr 2009
TL;DR: The spectrum measurement setup is presented, a new model for the duty cycle distribution is introduced and it is shown that the primary user signal bandwidth has major impact on the correlation properties of theduty cycle in the frequency domain.
Abstract: Several measurement campaigns have shown that numerous spectrum bands are vacant although licenses have been issued by the regulatory agencies. Dynamic spectrum access (DSA) has been proposed in order to alleviate this problem and increase the spectral utilization. In this paper we present our spectrum measurement setup and discuss lessons learned during our measurement activities. We compare measurement results gathered at three locations and show differences in the background noise processes. Additionally, we introduce a new model for the duty cycle distribution that has multiple applications in the DSA research. Finally, we show that the primary user signal bandwidth has major impact on the correlation properties of the duty cycle in the frequency domain.

105 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: A new multilevel clustering algorithm for Vehicular Ad-Hoc Networks (VANET) which is focused on the formation of stable, long living clusters for reliable communication, and which performs better than the popular classic approach (the Lowest Id algorithm).
Abstract: In this paper we present a new multilevel clustering algorithm for Vehicular Ad-Hoc Networks (VANET), which we will call the Density Based Clustering (DBC) algorithm. Our solution is focused on the formation of stable, long living clusters for reliable communication. Cluster formation is based on complex clustering metric which takes into account density of connection graph, link quality and traffic conditions. Tests performed in the simulation environment composed from VanetMobiSim and JiST/SWANS have shown that algorithm performs better than the popular classic approach (the Lowest Id algorithm [1]) - the clusters stability is significantly increased.

81 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: This work proposes a TCP performance evaluation testbed, called SVEET, on which real implementations of the TCP variants can be accurately evaluated under diverse network configurations and workloads in large-scale network settings.
Abstract: The ability to establish an objective comparison between high-performance TCP variants under diverse networking conditions and to obtain a quantitative assessment of their impact on the global network traffic is essential to a community-wide understanding of various design approaches. Small-scale experiments are insufficient for a comprehensive study of these TCP variants. We propose a TCP performance evaluation testbed, called SVEET, on which real implementations of the TCP variants can be accurately evaluated under diverse network configurations and workloads in large-scale network settings. This testbed combines real-time immersive simulation, emulation, machine and time virtualization techniques. We validate the testbed via extensive experiments and assess its capabilities through case studies involving real web services.

49 citations


Proceedings ArticleDOI
Timothy R. Newman1, An He1, Joseph Gaeddert1, Ben Hilburn1, Tamal Bose1, Jeffrey H. Reed1 
06 Apr 2009
TL;DR: An open cognitive radio network testbed provides the infrastructure for researchers at Virginia Tech and partner institutions to evaluate independently developed cognitive radio engines, sensing techniques, applications, protocols, performance metrics, and algorithms in a real world wireless environment, in contrast to a computer simulation or single node-to-single node environment.
Abstract: The Wireless @ VT research group has embarked on a effort to develop a unique testbed named the Virginia Tech Cognitive Radio Network (VT-CORNET), for the development, testing, and evaluation of cognitive engine techniques and cognitive radio network applications. An open cognitive radio network testbed provides the infrastructure for researchers at Virginia Tech and partner institutions to evaluate independently developed cognitive radio engines, sensing techniques, applications, protocols, performance metrics, and algorithms in a real world wireless environment, in contrast to a computer simulation or single node-to-single node environment.

35 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: The history of the project, the software architecture, the supported services and results of the various interoperability tests that have been performed between the UCT IMS Client and other freely available IMS Clients are described.
Abstract: The UCT IMS Client is a free open source implementation of a 3GPP IMS Client. The project was started with the goal of creating a flexible and extensible code base for researchers and industry specialists to use the many communication services offered by the IMS. Since its inception in 2006 the client has grown, both in terms of its stability and its feature set, and is used worldwide by IMS enthusiasts as a means to experiment with IMS without any associated risks or costs. This paper describes the history of the project, the software architecture, the supported services and provides results of the various interoperability tests that have been performed between the UCT IMS Client and other freely available IMS Clients.

32 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: A detailed path-latency model is introduced to be able to determine the overall propagation delays along the network paths more accurately, which leads to more precise geographic distance estimation between network routers and measurement nodes.
Abstract: This study outlines two novel techniques which can be used in the area of IP geolocation. First we introduce a detailed path-latency model to be able to determine the overall propagation delays along the network paths more accurately. This knowledge then leads to more precise geographic distance estimation between network routers and measurement nodes. In addition to the application of the detailed path-latency model, we describe a method which utilizes high-precision one-way delay measurements to further increase the accuracy of router geolocation techniques. The precise one-way delay values are used as a “path-constraint” to limit the overall geographic distance between the measurement nodes. The approach introduced in this paper can be used to localize all the network routers along the network path between the measurement nodes and can be combined with other existing geolocation techniques. The introduced techniques are validated in a wide range of experiments performed in the ETOMIC measurement infrastructure.

25 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: The VAN Testbed is described, developed under the Virtual Ad hoc Network (VAN) project, for testing applications over ad hoc networks, with a special focus on network management applications, and employs Xen-based virtualization to achieve resource scalability.
Abstract: Testing of applications for ad hoc networks poses a special technical challenge due to the difficulty of conducting experiments in an ad hoc network environment at a scale larger than a few nodes. One approach is to conduct experiments in a testbed that can imitate an ad hoc network. This requires the development of technologies that enable multiple instances of unmodified application software on a set of hosts to communicate via a simulated network that behaves like a real ad hoc network. In this paper, we describe the testbed developed under the Virtual Ad hoc Network (VAN) project1 for testing applications over ad hoc networks, with a special focus on network management applications. The testbed employs Xen-based virtualization to achieve resource scalability. The infrastructure for the testbed provides an integrated platform consisting of virtual nodes running the actual software under test, augmented with a simulated network environment. Our goal is to enable software testing over large-scale (500–1000 nodes) ad hoc networks using the VAN Testbed.

24 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: The proposed MRL-CC, a Multi-agent Reinforcement Learning based multi-hop mesh Cooperative Communication mechanism for wireless sensor networks performs well in terms of a number of QoS metrics, and fits well in large-scale networks and highly dynamic environments.
Abstract: Cooperative communications have been demonstrated to be effective in combating the multiple fading effects in wireless networks, and improving the network performance in terms of adaptivity, reliability, data throughput and network life time. In this paper, we investigate the use of cooperative communications for quality of service (QoS) provisioning in resource-constrained wireless sensor networks, and propose MRL-CC, a Multi-agent Reinforcement Learning based multi-hop mesh Cooperative Communication mechanism for wireless sensor networks. In order to disseminate data reliably in MRL-CC, a multi-hop mesh cooperative structure is first constructed. Then a cooperative mechanism with cooperative partner assignments, and coding and transmission schemes is implemented using a multi-agent reinforcement learning algorithm. We compare the network performance of MRL-CC with MMCC [1], a Multi-hop Mesh structure based Cooperative Communication scheme, and investigate the impacts of network traffic load, interference and sensor node's mobility on the network performance. Simulation results show that MRL-CC performs well in terms of a number of QoS metrics, and fits well in large-scale networks and highly dynamic environments.

24 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper proposes a novel method which dynamically adapts the transmission rate and FEC for video multicast over multirate wireless networks and results show that the proposed system significantly improves the multicast system performance.
Abstract: Video multicast over Wireless Local Area Networks (WLANs) faces many challenges due to varying channel conditions and limited bandwidth. A promising solution to this problem is the use of packet level Forward Error Correction (FEC) mechanisms. However, the adjustment of the FEC rate is not a trivial issue due to the dynamic wireless environment. This decision becomes more complicated if we consider the multi-rate capability of the existing wireless LAN technology. In this paper, we propose a novel method which dynamically adapts the transmission rate and FEC for video multicast over multirate wireless networks. In order to evaluate the system experimentally, we implemented a prototype using open source drivers and socket programming. Our experimental results show that the proposed system significantly improves the multicast system performance.

23 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper presents the design of a prototype intersection collision warning system based on Vehicle Infrastructure Integration (VII), in which appropriate alarm messages are disseminated by the roadside unit in case it predicts a potential collision at the intersection to notify endangered vehicles of the moving car which is about to cross the red light.
Abstract: Vehicle collisions at intersections account for a large percentage of overall traffic accidents, a good portion of which are fatal. A large number of these accidents can be avoided by a warning system which makes a driver aware of potential collisions on the road, thus allowing the driver enough time to prevent such situations. This paper presents the design of a prototype intersection collision warning system based on Vehicle Infrastructure Integration (VII). Moreover, we design a system consisting of roadside and on-board units, in which appropriate alarm messages are disseminated by the roadside unit in case it predicts a potential collision at the intersection to notify endangered vehicles of the moving car which is about to cross the red light. Furthermore, we implemented the proposed configuration in a real world scenario whose promising results in the form of negligible probability of false alarm, renders the system a fine benchmark for future more detailed and realistic studies. Underlying the system are wireless communications, positioning technology, and information technology that ensure accurate and timely safety information.

20 citations


Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper focuses on a proof-of-concept implementation that integrates IEEE 802.21 services and a pre-authentication framework, realizing different possible usage scenarios to optimize handover performance.
Abstract: Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies together with increasing use of real time multimedia applications is creating strong demand for handover solutions that can seamlessly and securely transfer user sessions across different access technologies. In this paper, we discuss how the IEEE 802.21 standard and its services address the challenges of seamless mobility for multi-interface devices. We focus on a proof-of-concept implementation that integrates IEEE 802.21 services and a pre-authentication framework, realizing different possible usage scenarios to optimize handover performance. We describe the implementation of two handover scenarios using the 802.21 Services: the first one is initiated by the mobile node and the second one is initiated by the operator network. We compare the two scenarios and discuss their respective benefits. Finally, we describe the implementation challenges and lessons learned through this exercise.

Proceedings ArticleDOI
Yue Zhao1, Xuming Fang1, Xiaopeng Hu1, Zhengguang Zhao1, Yan Long1 
06 Apr 2009
TL;DR: A new fractional frequency reuse scheme to assign radio resources in OFDMA multi-hop networks to reduce inter-cell interference and maintain the sector frequency reuse factor at 1.
Abstract: For the next generation wireless communication systems, inter-cell interference (ICI) is the primary cause of performance degradation in cell edge mobile stations of OFDMA multi-hop cellular networks with the frequency reuse pattern (1, 3, 1). This paper introduces a new fractional frequency reuse scheme to assign radio resources in OFDMA multi-hop networks to reduce inter-cell interference and maintain the sector frequency reuse factor at 1. Through the numerical analysis, we find that this scheme can yield higher SINR and improve the system capacity. Furthermore, the results also indicate that fractional frequency reuse relay system with local forwarding scheme can achieve higher throughput than local forwarding scheme in conventional relay system.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: In this paper an integral VANET testbed is evaluated, using 802.11b and a multi-hop network managed by the Optimized Link State Routing protocol (OLSR) and results differ from traditional two-hop and staticroute tests, presenting a more realistic study.
Abstract: Evaluation of vehicular ad-hoc networks (VANETs) over real environments is still a remaining issue for most researchers. There are some works dealing with common 802.11 analysis over real vehicular environments, which carry out performance tests to measure the quality of the communication channel and justify results according to physical and MAC conditions. There are only a few works regarding multi-hop experimentation in this field, and even less (if not none) testing multi-hop protocols. In this paper an integral VANET testbed is evaluated, using 802.11b and a multi-hop network managed by the Optimized Link State Routing protocol (OLSR). Up to four vehicles are used over urban and highway environments to study the VANET performance, and different metrics are used to analyse the results in terms of delay, bandwidth, packet loss and distance between nodes. Furthermore, a deeper analysis is carried out to study the route followed by packets end to end, which enables us to count the number of hops and detect the links where packets are lost. Because a routing protocol is used, results differ from traditional two-hop and staticroute tests, presenting a more realistic study. OLSR is considered as a good reference point for the research community, although it is not the most suitable protocol for vehicular environments, as results show.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This document proposes a techno-economic model to support the new requirements of fixed and nomadic users and the increasing demand of “quad-play” services, including video, voice, data and mobility.
Abstract: The two main challenges for the access networks are the increasing bandwidth demand and mobility trends. The “triple play” services required (Internet, telephone and TV services) lead to a great increase in bandwidth demand. However, the existing access networks are not able to support this increase, and the capacity to delivery broadband services remain as a challenge (“last mile problem”). The access network remains a bottleneck in terms of the bandwidth and service quality it affords the end user. Besides the bandwidth, other great challenge to access networks is the mobility and the user need to have internet access anywhere and anytime. Then, the increasing demand of “quad-play” (also known as quadruple-play) services, including video, voice, data and mobility, have created new challenges to the modern broadband wireless/wired access networks. This document proposes a techno-economic model to support the new requirements of fixed and nomadic users.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: An architecture for creating experimental environments across multiple cooperating Emulab-based testbeds, called the DETER Federation Architecture (DFA), which uses cooperative resource allocation and multiple-level testbed access to create a cohesive environment for experimentation.
Abstract: We describe an architecture for creating experimental environments across multiple cooperating Emulab-based testbeds, called the DETER Federation Architecture (DFA). The system uses cooperative resource allocation and multiple-level testbed access to create a cohesive environment for experimentation. Testbeds that contribute resources continue to exert their own resource allocation and access policies. The architecture is designed to scale. We describe a prototype implementation.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: It is found that a video-specific utility function achieves significant improvements on received video quality over a general purpose utility function, indicating the efficacy of cross-layer design and more importantly, the need for adopting dynamic situation- and application-aware utility functions at the CE, rather than a predefined static one.
Abstract: Cognitive Radio (CR) is a new wireless communications and networking paradigm that is enabled by the Software Defined Radio (SDR) technology and a recent change in spectrum regulation policy. As the first commercial application of CR technology, IEEE 802.22 wireless regional area networks (WRAN) aim to offer broadband wireless access by efficiently utilizing “white spaces” in the broadcast TV bands. In this paper, we evaluate the performance of an IEEE 802.22 WRAN base station (BS) cognitive engine (CE) testbed developed at Wireless@Virginia Tech on supporting video applications. We investigate the important problem of utility function selection and its impact on the received video quality. Through testbed experiments, we find that a video-specific utility function achieves significant improvements on received video quality over a general purpose utility function, indicating the efficacy of cross-layer design and more importantly, the need for adopting dynamic situation- and application-aware utility functions at the CE, rather than a predefined static one.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This work presents Sensei - a nomadic, relocatable, wireless sensor network (WSN) testbed with support for mobile nodes and supports reproducibility mobility in the testbed, using robots or humans as actuators with movement patterns defined in mobility scripts.
Abstract: We present Sensei - a nomadic, relocatable, wireless sensor network (WSN) testbed with support for mobile nodes. The nomadism makes it possible to evaluate a WSN application in different environments ranging from lab environments to in-situ installations to prototype deployments. Other WSN testbeds are often static and can not easily mobed between sites. We also support reproducibility mobility in the testbed, using robots or humans as actuators with movement patterns defined in mobility scripts.

Journal ArticleDOI
06 Apr 2009
TL;DR: Two tools are developed for the DETER testbed to aid in worm experimentation: the PAWS simulator for Internet-wide worm propagation studies and the THE AUTHORS emulator for analysis of worm spread and defense strategies in local area networks.
Abstract: Worm experimentation is challenging for researchers today because of the lack of standardized tools to simulate and emulate worm spreads in a realistic setting. We have developed two tools for the DETER testbed to aid in worm experimentation: the PAWS simulator for Internet-wide worm propagation studies and the WE emulator for analysis of worm spread and defense strategies in local area networks. We evaluate performance and fidelity of our tools by replicating results from recently published research. Both tools can be easily configured as per user specifications, facilitate comparison with past research and reduce the barrier to entry for worm research.

Journal ArticleDOI
06 Apr 2009
TL;DR: Experimental results show that the overhead when using a service composition scheme does not prevent the grid from giving fast workflow execution, and a service-oriented grid testbed is evaluated, able to get executions in the order of five times faster using the grid when compared to the local execution.
Abstract: Grid computing has emerged as a powerful environment for parallel processing. Nowadays, many organizations participate in one or more grid computing infrastructures, sharing computational resources to achieve high computational power and/or very large storage capacities. Mostly, these grids provide application interfaces for the user to submit jobs or workflows. These interfaces receive the submissions and distribute them among the grid resources. In this paper we evaluate a service-oriented grid testbed. Jobs are submitted through a workflow manager using a workflow composition language which allows services to be invoked sequentially or in parallel. Experimental results show that the overhead when using a service composition scheme does not prevent the grid from giving fast workflow execution. In our testbed, for a median filter application, we were able to get executions in the order of five times faster using the grid when compared to the local execution.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper presents MINER, a programmable measurement infrastructure that integrates existing measurement tools and provides its users higher-level services on top of them, which enables users to define measurement activities, schedule executions and retrieve their results.
Abstract: Network measurements often require the coordinated use of multiple tools on distributed vantage points. Without any form of supporting command and control system, the management and execution of a systematic measurement study is a tedious mission. In this paper we present MINER which seeks to simplify this task. MINER is a programmable measurement infrastructure that integrates existing measurement tools and provides its users higher-level services on top of them. It enables users to define measurement activities, schedule executions and retrieve their results. The services are accessible via a tool-agnostic and unified programming interface with which measurement applications can be developed. We discuss MINER's requirements and design considerations and present a modular implementation that can be flexibly extended through plugins. Finally, we report on usage scenarios and directions for future work.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: In this paper, experiments on interoperability testing of presence service on IMS platform find that a number of functionalities could not be tested because they are not supported by IMS clients.
Abstract: In this paper, we perform experiments on interoperability testing of presence service on IMS platform. Open source implementations such as an IMS platform, a presence server, an XCAP server, and IMS clients are deployed to establish testbed for interoperability testing of presence service. Test cases for SIMPLE presence protocol developed by OMA are applied to our testbed and test results are analyzed in detail. In our experiments, we covered the basic functionalities of the presence service and the interaction between a client and an XCAP server for intra-domain case. And then we explained the testbeds for inter-domain cases and discussed briefly the differences with intra-domain case. As a result, we found that a number of functionalities could not be tested because they are not supported by IMS clients. Also we found a number of problems in presence server and IMS clients, which results in a number of fail verdicts for some test cases.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: The design issues in building a large-scale WLAN testbed for evaluating centralized control algorithms and how these requirements are met are discussed, and experimental results that showcase the testbed's unique characteristics are presented.
Abstract: In this paper, we describe a wireless testbed for centralized control. Centralized WLAN systems make use of a central controller that dynamically configures the network based on measured environmental conditions. Such networks are becoming increasingly common in many enterprise and campus deployments today. However, many aspects of centralized WLAN architectures, such as wired delay and delay jitter properties are poorly understood. This necessitates an in-depth empirical study of such systems. We describe the design issues in building a large-scale WLAN testbed for evaluating centralized control algorithms. The need for centralized control introduces some key requirements that cannot be met by earlier designs. We discuss these requirements, show how they are met by our testbed, and present experimental results that showcase the testbed's unique characteristics.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper presents a bandwidth occupied time proportion fair MAC algorithm (BOTP-FMAC) for WLAN and Wireless Mesh Network (WMN) that substantially improves the fairness and attains a greater aggregate throughput.
Abstract: This paper presents a bandwidth occupied time proportion fair MAC algorithm (BOTP-FMAC) for WLAN and Wireless Mesh Network (WMN). It aims to address the unfairness problem in enhanced distributed channel access (EDCA) mechanism, in which higher-priority streaming traffic flows intend to severely deprive the access opportunity of lower-priority traffic flows due to the capture effect, especially when the network load is near saturation. By dynamically tuning the parameters of channel contention and the threshold of bandwidth occupied time proportion for priority queue adaptively, BOTP-FMAC algorithm can achieve a weighted fair allocation of the bandwidth resource among different traffic flows. The simulation results indicate that our proposed algorithm substantially improves the fairness and attains a greater aggregate throughput. Additionally, it is easy to carry out without generating network overhead.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: The Pan-European laboratory - Panlab - is based on federation of distributed testbeds that are interconnected, providing access to required platforms, networks and services for broad interoperability testing and enabling the trial and evaluation of service concepts, technologies, system solutions and business models.
Abstract: The Pan-European laboratory - Panlab - is based on federation of distributed testbeds that are interconnected, providing access to required platforms, networks and services for broad interoperability testing and enabling the trial and evaluation of service concepts, technologies, system solutions and business models. In this context a testbed federation is the interconnection of two or more independent testbeds for the temporary creation of a richer environment for testing and experimentation, and for the increased multilateral benefit of the users of the individual independent testbeds. The technical infrastructure that supports the federation is based on a web service through which available testing resources can be queried and requested. The available resources are stored in a repository, and a processing engine is able to identify, locate and provision the requested testing infrastructure, based on the testing users' requirements. The concept is implemented using a gateway approach at the border of each federated testbed. Each testbed is an independent administrative domain and implements a reference point specification in its gateway.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: DORII (Deployment of Remote Instrumentation Infrastructure) is to build and operate a test bed addressing different areas of eScience, including oceanographic applications, earthquake engineering, and large-scale physics experiments on synchrotron light.
Abstract: Much interest has arisen recently on the access to and management of remote instrumentation and laboratory equipment in general. The complexity of activities related to these topics can be summarized under the name of Remote Instrumentation Services, where the term “instrumentation” includes any kind of experimental equipment, and the term “services” underlines the general framework whereby the instrumental resources should be accessed (i.e., the Service Oriented Architecture). Building on the foundations of previous European projects, the aim of DORII (Deployment of Remote Instrumentation Infrastructure) is to build and operate a test bed addressing different areas of eScience. These include oceanographic applications, earthquake engineering, and large-scale physics experiments on synchrotron light. The paper describes the characteristics and the design of the test bed stemming from the applications' requirements, in terms of networking and middleware, and its current status of development.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: A Multilayered Policy Control architecture is proposed that extends the general resource management function being standardized; this extended architecture gives application developers greater control over the way their services are treated in the transport layer.
Abstract: Policy Based Resource Management will form the cornerstone of service differentiation that will drive IMS service deployment. While the IMS specifications are largely finalized, the policy based QoS provisioning architecture still faces many deployment challenges including flexible, application driven policy control, end to end policy provisioning and policy refinement. To accelerate the maturity of this technology open test-beds are necessary to expose the complex systems to an open set of developers. This paper proposes a Multilayered Policy Control architecture that extends the general resource management function being standardized; this extended architecture gives application developers greater control over the way their services are treated in the transport layer. Furthermore the architecture is implemented in the form of a 3GPP compliant, open source and freely distributed test-bed architecture - the open areas of policy representation, application-policy interaction, policy profiling and policy refinement are addressed. This open test-bed will serve to foster innovation in the field, increase collaborative co-operation and accelerate the maturity of these technologies. The framework is subjected to vigorous validation and evaluation tests - while the effects the architecture has on session setup delay and signaling overhead are not insignificant they are found to be acceptable.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper designed and implemented a real native IPv6 UMTS-LAN testbed equipped with novel IPv6-based mobile technologies, such providing ideal conditions for SCTP multihoming performance analysis and shows that accurate S CTP parameter setup can significantly decrease the handover delay and eliminate the data transmission interrupts.
Abstract: Multihoming is one of the most attractive features of SCTP (Stream Control Transmission Protocol) aiming to make this prosperous transport scheme competitive in mobile environments when the mobile hosts are equipped with multiple interfaces. The complementary characteristic of the 3G UMTS (Universal Mobile Telecommunications System) and WLAN (Wireless Local Area Network) architectures motivates operators to integrate these two successful technologies. Recently spreading wireless devices are increasingly provided with multiple networking interfaces such enabling end-users to access Internet services using e.g. the WLAN's higher bandwidth wherever available, and connecting to the UMTS network in other cases. This paper investigates the performance of multihomed SCTP hosts through extensive experimental studies in such an integrated heterogeneous environment. In order to do this we designed and implemented a real native IPv6 UMTS-LAN testbed equipped with novel IPv6-based mobile technologies, such providing ideal conditions for SCTP multihoming performance analysis. In this testbed architecture we analyzed numerous settings to measure the handover behavior of the protocol in terms of handover effectiveness, link changeover characteristics, throughput and transmission delay. As our results show, accurate SCTP parameter setup can significantly decrease the handover delay and eliminate the data transmission interrupts.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: An emulation platform based on open-source software that allows to evaluate a Carrier Ethernet variant called Ethernet Label Switching (ELS) and has the possibility to perform time and performance benchmarking and traffic generation using standard Linux software.
Abstract: Last decades bridged Ethernet has been the de facto standard layer 2 technology for LAN environments. This is mainly because it is easy to deploy, it has low cost and is relatively robust. These attractive properties together with highly increasing PHY speeds result in several initiatives of research projects and standardization bodies to extend Ethernet such as to use the technology in carrier environments. However these Carrier Ethernet solutions are difficult to test with given simulation tools. This paper presents an emulation platform based on open-source software that allows to evaluate a Carrier Ethernet variant called Ethernet Label Switching (ELS). The platform allows various topology setups and has the possibility to perform time and performance benchmarking and traffic generation using standard Linux software. We will present the architecture of the emulation framework and show promising results in base setups.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: This paper presents a testbed implementation of an inter-carrier GMPLS (Generalized Multi Protocol Label Switching) service architecture recently proposed, which couples the Path Computation Element (PCE)-based control plane with a service plane managing discovery, composition and activation functions of inter- carrier service elements.
Abstract: This paper presents a testbed implementation of an inter-carrier GMPLS (Generalized Multi Protocol Label Switching) service architecture recently proposed. This architecture couples the Path Computation Element (PCE)-based control plane with a service plane managing discovery, composition and activation functions of inter-carrier service elements. The testbed implements the required PCE Communication Protocol (PCEP) and Resource Reservation Protocol with Traffic Engineering (RSVP-TE) extensions, together with service request filtering operations performed with a policy based architecture1.

Proceedings ArticleDOI
06 Apr 2009
TL;DR: A system, where digital video can be corrupted according to established loss patterns and the effect is measured automatically and the corrupted video is then used as input for user tests and their results are analyzed and compared with the automatically generated results.
Abstract: Currently, a complete system for analyzing the effect of packet loss on a viewer's perception is not available. Given the popularity of digital video and the growing interest in live video streams where channel coding errors cannot be corrected, such a system would give great insight into the problem of video corruption through transmission errors and how they are perceived by the user. In this paper we introduce such a system, where digital video can be corrupted according to established loss patterns and the effect is measured automatically. The corrupted video is then used as input for user tests. Their results are analyzed and compared with the automatically generated. Within this paper we present the complete testing system that makes use of existing software as well as introducing new modules and extensions. With the current configuration the system can test packet loss in H.264 coded video streams and produce a statistical analysis detailing the results. The system is fully modular allowing for future developments such as other types of statistical analysis, different video measurements and new video codecs.