Internet Protocol (internet + protocol)

Distribution by Scientific Domains

Selected Abstracts

Optimal Design of the Online Auction Channel: Analytical, Empirical, and Computational Insights,

Ravi Bapna
ABSTRACT The focus of this study is on business-to-consumer (B2C) online auctions made possible by the advent of electronic commerce over an open-source, ubiquitous Internet Protocol (IP) computer network. This work presents an analytical model that characterizes the revenue generation process for a popular B2C online auction, namely, Yankee auctions. Such auctions sell multiple identical units of a good to multiple buyers using an ascending and open auction mechanism. The methodologies used to validate the analytical model range from empirical analysis to simulation. A key contribution of this study is the design of a partitioning scheme of the discrete valuation space of the bidders such that equilibrium points with higher revenue structures become identifiable and feasible. Our analysis indicates that the auctioneers are, most of the time, far away from the optimal choice of key control factors such as the bid increment, resulting in substantial losses in a market with already tight margins. With this in mind, we put forward a portfolio of tools, varying in their level of abstraction and information intensity requirements, which help auctioneers maximize their revenues. [source]

End-to-end network delay model for heavy-tailed environments

David Muñoz-Rodríguez
Adequate quality of Internet Protocol (IP) services demand low transmission delays. However, packets traveling in a network are subject to a variety of delays that degrade severely the quality of service in real-time applications. This paper presents a general packet jitter-assessment methodology for a multi-node path in the presence of heavy-tailed traffic. Using the extreme-value theory, it is shown that delay performance is governed by a proposed networking-processing factor |T|lambda dependent on the traffic characteristics, the processing time along the path segments and the number of nodes in a route. |T|lambda allows the establishment of design constraints and the definition of a feasibility space for a routing algorithm in order to guarantee a quality of service (QoS). Copyright © 2003 AEI. [source]

Performance of delay-sensitive traffic in multi-layered satellite IP networks with on-board processing capability

Suzan Bayhan
Abstract In this article, performance of delay-sensitive traffic in multi-layered satellite Internet Protocol (IP) networks with on-board processing (OBP) capability is investigated. With OBP, a satellite can process the received data, and according to the nature of application, it can decide on the transmission properties. First, we present a concise overview of relevant aspects of satellite networks to delay-sensitive traffic and routing. Then, in order to improve the system performance for delay-sensitive traffic, specifically Voice over Internet Protocol (VoIP), a novel adaptive routing mechanism in two-layered satellite network considering the network's real-time information is introduced and evaluated. Adaptive Routing Protocol for Quality of Service (ARPQ) utilizes OBP and avoids congestion by distributing traffic load between medium-Earth orbit and low-Earth orbit layers. We utilize a prioritized queueing policy to satisfy quality-of-service (QoS) requirements of delay-sensitive applications while evading non-real-time traffic suffer low performance level. The simulation results verify that multi-layered satellite networks with OBP capabilities and QoS mechanisms are essential for feasibility of packet-based high-quality delay-sensitive services which are expected to be the vital components of next-generation communications networks. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Impact of Redhat IPv6 router on heterogeneous host connections

Sulaiman Syed Mohamed
Abstract Internet's popularity has been expanding on dramatic pace and the number of people getting connected to it multiplies regularly. With this high demand, the current Internet Protocol (IPv4) has reached its limits. The next generation Internet Protocol version6 (IPv6) has been incorporated into various operating systems. The motivation behind this work is how well IPv6 co-operates with various operating systems. The performance of the IP stack, together with the behaviour of the OS greatly affects the efficiency of network applications built on top of it. The acceptance of IPv6 implementations on various operating systems heavily relies on the end-user performance. In this paper, we propose to analyse these various IPv6 implementations for its host and router-level supports. In this paper, we investigate the impact of Redhat-based IPv6 router on IPv6 stacks of three different operating systems namely, Windows2003, Redhat Linux 9.0 (Redhat9.0) and FreeBSD4.9. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Preparing network configurations for IPv6 renumbering

Damien Leroy
The difficulty of renumbering a network,i.e., adding and removing an Internet Protocol (IP) prefix due to a provider change or a network merger,is a real issue for most network administrators. In this paper, we propose a set of macros that can be used in configuration files. These allow network administrators to write generic configurations that are independent of the public IPv6 prefixes allocated to their network. We explain how to apply our macros to key configuration files, namely firewall access lists, Domain Name Service and Dynamic Host Configuration Protocol, and how to use this mechanism in a full renumbering process. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Study of delay patterns of weighted voice traffic of end-to-end users on the VoIP network

Jeong-Soo Han
In this paper we study delay patterns of weighted voice traffic of end-to-end users on the Voice over Internet Protocol (VoIP) network. We compare the delay performance of voice traffic which varies with queue management techniques such as First-In First-Out (FIFO) and Weighted Fair Queuing (WFQ) and voice codec algorithms such as G.723 and G.729 and select an optimal algorithm. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Experience with Delay-Tolerant Networking from orbit,

W. Ivancic
Abstract We describe the first use from space of the Bundle Protocol for Delay-Tolerant Networking (DTN) and lessons learned from experiments made and experience gained with this protocol. The Disaster Monitoring Constellation (DMC), constructed by Surrey Satellite Technology Ltd (SSTL), is a multiple-satellite Earth-imaging low-Earth-orbit sensor network in which recorded image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a disruption-tolerant network. Originally developed for the ,Interplanetary Internet,' DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a ,bundle' architecture and protocol. The DMC is technically advanced in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites' use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation's UK-DMC satellite. Earth images are downloaded from the satellites using a custom IP-based high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with the use of DTNRG bundle concepts onboard the UK-DMC satellite, by examining how Saratoga can be used as a DTN ,convergence layer' to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. Our practical experience with the first successful use of the DTNRG Bundle Protocol in a space environment gives us insights into the design of the Bundle Protocol and enables us to identify issues that must be addressed before wider deployment of the Bundle Protocol. Published in 2010 by John Wiley & Sons, Ltd. [source]

Fusion of digital television, broadband Internet and mobile communications,Part I: Enabling technologies

F. L. C. Ong
Abstract The introduction of digital video broadcasting (DVB) satellite systems has become an important tool for future mobile communication and is currently a focus in several research areas such as the integration of DVB satellite systems with different wireless technologies. This tutorial consists of two parts, Enabling technologies and Future service scenarios, which aims to provide an introduction to the current state-of-the-art of DVB standards over satellite and its fusion with mobile and Internet technologies. This paper, Enabling technologies, focuses on providing an overview of the different technologies and issues that facilitates better understanding of the current and future operational scenarios, whereas the second paper, Future service scenarios will emphasize future research directions in this research area. In the first part, the paper will initially be focused on the introduction of different DVB satellite systems, i.e. DVB- via satellite (DVB-S), DVB return channel by satellite (DVB-RCS) and second-generation DVB system for broadband satellite services (DVB-S2). This is then followed by a description of the different Internet Protocol (IP) technologies used to support macro- and micro-mobility and the migration strategies from IP version 4 (IPv4) to IP version 6 (IPv6). Finally, the different security mechanisms for the DVB system and end-to-end satellite network are addressed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

On the impact of the solution representation for the Internet Protocol Network Design Problem with max-hop constraints

L. De Giovanni
Abstract The IP (Internet Protocol) Network Design Problem can be shortly stated as follows. Given a set of nodes and a set of traffic demands, we want to determine the minimum cost capacity installation such that all the traffic is routed. Capacity is provided by means of links of a given capacity and traffic must be loaded on the network according to the OSPF-ECM (Open Shortest Path First,Equal Commodity Multiflow) protocol, with additional constraints on the maximum number of hops. The problem is strongly NP-Hard, and the literature proposes local search-based heuristics that do not take into account max-hop constraints, or assume a simplified OSPF routing. The core in a local search approach is the network loading algorithm for the evaluation of the neighbor solutions costs. It presents critical aspects concerning both computational efficiency and memory requirements. Starting from a tabu search prototype, we show how these aspects deeply impact on the design of a local search procedure, even at the logical level. We present several properties of the related network loading problem, that allow to overcome the critical issues and lead to an efficient solution evaluation. © 2004 Wiley Periodicals, Inc. NETWORKS, VoL. 44(2), 73,83 2004 [source]

Optimization of Internet Protocol network design and routing

Kaj Holmberg
Abstract We consider network design and routing for Internet Protocol (IP) traffic. The design problem concerns capacity dimensioning of communication links, where the design cost consists of fixed charges and linear capacity expansion costs. The optimization problem also concerns determining the amount of traffic demand to be carried by the network and the metric used by a shortest path routing protocol. We present a novel linear mixed-integer mathematical formulation and two heuristic solution procedures. The first heuristic uses mixed-integer programming to generate a sequence of routing solutions. The second solution approach is a simulated annealing meta heuristic. Computational experiments for synthesized and real-life networks show that high-quality solutions can be obtained by both approaches. © 2003 Wiley Periodicals, Inc. [source]

Authenticating displayed names in telephony

Stanley T. Chow
In both traditional and Internet Protocol (IP) telephony, a caller ID number is subject to control and verification, whereas the displayable caller ID name is a convenience feature which operators have no control over. It may be arbitrarily set by the caller. Voice phishing can exploit this weakness,e.g., make a call spoofing the name of a bank and ask for account information. We present a framework that allows each call participant to authenticate the displayed name of other parties via public name registries and International Telecommunication Union Telecom Standardization Sector (ITU-T) X.509 certificates. The authentication can work end-to-end, on-demand, for both called and calling party's name, for Voice over Internet Protocol (VoIP), landline, or mobile endpoints. The framework is flexible, does not require global public key infrastructure (PKI), and allows concerned financial, medical, and legal institutions to delegate the use of their authenticated names to employees outside the office as well as outsourcing companies. A proof-of-concept implementation is also presented. © 2009 Alcatel-Lucent. [source]

Caching architectures and optimization strategies for IPTV networks

Bill Krogfoss
This paper looks at the issue of optimization for caching architectures for Internet Protocol (IP) router networks for unicast video. There are several optimization challenges when designing caching architectures. These include where the caches should be located, how much memory is needed per cache, which services should be cached where, and whether hierarchical or single level caching should be used. This paper investigates topology issues and the difficulty of caching long tail content. We propose some solutions to cache architecture optimization and partitioning and look at the issue of caching long tail content. © 2008 Alcatel-Lucent. [source]

Protecting IPTV against packet loss: Techniques and trade-offs

Natalie Degrande
Packet loss ratios that are harmless to the quality of data and Voice over Internet Protocol (VoIP) services may still seriously jeopardize that of Internet Protocol television (IPTV) services. In digital subscriber line (DSL)-based access networks, the last mile in particular suffers from packet loss, but other parts of the network may do so too. While on the last mile link, the packet loss is due to bit errors, in other parts of the network it is caused by buffers overflowing or the network experiencing (short) outages due to link or node failures. To retrieve lost packets, the application layer (AL) can use either a forward error correction (FEC) or a retransmission scheme. These schemes, when properly tuned, increase the quality of an IPTV service to an adequate level, at the expense of some overhead bit rate, extra latency, and possibly an increase in channel change time. This paper compares the performance of FEC schemes based on Reed-Solomon (RS) codes with that of retransmission schemes, all tuned to conform to the same maximum overhead bit rate allowed on the last mile link and on the feeder link, and their possible impact on the channel change time. We take into account two kinds of loss processes that can occur: isolated packet losses and burst packet losses. In almost all scenarios, retransmission outperforms FEC. © 2008 Alcatel-Lucent. [source]

IMS network signaling peering: Challenges and proposal

Jean-Philippe Joseph
IP Multimedia Subsystem (IMS) network peering is a key enabler that will help accelerate deployment of next-generation IMS-based networks. Today's early deployments of dispersed IMS networks require public switched telephone network (PSTN)/public land mobile network (PLMN) bridges for network interconnection between IMS islands. The PSTN/PLMN bridging arrangement is inefficient, however, in that it results in unnecessary settlements for the carriers. It further impedes the implementation of rich multimedia and Voice over IP (VoIP)-related services that require end-to-end Internet Protocol (IP) connectivity. Last, it perpetuates the reliance on the existing PSTN/PLMN network for voice calls among subscribers served by different IMS-based carriers. This paper analyzes in detail the IMS peering challenges from the perspective of Session Initiation Protocol (SIP) signaling peering. It discusses issues related to the routing of SIP messages, and addressing, address resolution, and discovery of peering points for IMS signaling peering. It further establishes that a new routing algorithm is needed that will allow signaling peering points to dynamically discover the "best" transit network among others for reaching a destination. In closing, it presents a high-level IMS signaling routing process that includes, among other benefits, support for number portability as a key function for inter-carrier IMS peering. © 2008 Alcatel-Lucent. [source]

Advanced IMS client supporting secure signaling

Ramana Isukapalli
With recent advances in core and access networks and the availability of increased bandwidth and sophisticated devices for end users, there is an increased demand for client applications running on mobile devices, such as laptops and handheld devices, to support real time applications like Voice over Internet Protocol (VoIP) and streaming video, apart from traditional applications like web browsing. This paper presents a prototype IP Multimedia Subsystem (IMS) client, which serves as a VoIP client to set up calls between Internet Protocol (IP) devices and interworks with circuit-switched networks to deliver calls to public switched telephone network (PSTN) phones. It implements supplementary services (including call waiting, call transfer, and call forwarding); supports multimedia ringing, short message service/multimedia messaging service (SMS/MMS), audio/video conferencing, and peer-to-peer video; and it can deliver a call to a user (as opposed to a device) by simultaneously ringing multiple devices registered by the user. Further, to address various security concerns, the client supports Hypertext Transfer Protocol (HTTP) digest authentication using Message Digest 5 (MD5) cryptographic function authentication and key agreement (AKA) and can create secure tunnels to the core network using IP security (IPsec). © 2008 Alcatel-Lucent. [source]

Monitoring infrastructure for converged networks and services

Shipra Agrawal
Network convergence is enabling service providers to deploy a wide range of services such as Voice over Internet Protocol (VoIP), Internet Protocol television (IPTV), and push-to-talk on the same underlying IP networks. Each service has unique performance requirements from the network, and IP networks have not been designed to satisfy these diverse requirements easily. These requirements drive the need for a robust, scalable, and easy-to-use network management platform that enables service providers to monitor and manage their networks to provide the necessary quality, availability, and security. In this paper, we describe monitoring mechanisms that give service providers critical information on the performance of their networks at a per-user, per-service granularity in real time. This allows the service providers to ensure that their networks adequately satisfy the requirements of the various services. We present various methods to acquire data, which can be analyzed to determine the performance of the network. This platform enables service providers to offer carrier grade services over their converged networks, giving their customers a high-quality experience. © 2007 Alcatel-Lucent. [source]

CDMA 1x Ev-DO security

Semyon Mizikovsky
CDMA 1x evolution,data optimized (1x EV-DO) is defined in the TIA/EIA IS-856 and IS-835 standards. The security of 1x EV-DO offers authentication, integrity, and encryption capabilities. 1x EV-DO supports authentication of the access terminal (AT) to authorize access to the wireless network, as well as authentication of a subscription to authorize access to the Internet Protocol (IP) network. The system also provides session security via re-authenticating the AT during a session to prevent 1x EV-DO session hijacking and to protect integrity of the user packets. This paper will outline security threats to the 1x EV-DO system, security algorithms, authentication and authorization procedures, and ciphering procedures. The 1x EV-DO security will be detailed here for key exchange, authentication, and encryption functions by supporting the following protocols: security protocol, key exchange protocol, authentication protocol, and encryption protocol. Finally, a summary of 1x EV-DO security evolution will be presented © 2007 Alcatel-Lucent. [source]

Optimal availability and security for IMS-based VoIP networks

Himanshu Pant
Consumers are continuously looking for ways of improving their productivity, simplifying their tasks, and streamlining communications both domestically and globally. This has resulted in the need to support different applications and thus the ongoing process of migrating many network services from traditional circuit-switched networks to Internet Protocol (IP) to converged networks. The circuit-switched public switched telephone network (PSTN) was a closed network where cyber-security threats were not amajor issue. With the advent of converged networks and IP-based services, service providers, government, and enterprises are concerned about the growing security threat. The new networks and equipment will be subject to many types of threats and their vulnerabilities may expose mission critical applications and infrastructure to risk. Realization of these threats can lead to service outage. Today's communications service provider must decide how to treat the effects of security breaches so as to minimize service downtime. This paper highlights amethodology, with examples to identify the effect of security-related failures and the critical design factors to be considered when modeling service reliability. The ITU-T X.805 standard (now also ISO standard 18028-2), based on the Bell Labs security model, is used to evaluate potential high impact threats and vulnerabilities. The analysis uses the Bell Labs domain technique known as security domain evaluation. One of the critical outputs provides a prioritized understanding of the threats the network is exposed to and the vulnerabilities in the security architecture. The next step in themethodology includes incorporating the threats (vulnerabilities) identified in a reliability model and quantifying the corresponding service degradation. In this paper, these concepts are applied to IP Multimedia Subsystem (IMS)-based VoIP (Voice over IP) networks. Using reliability metrics, our analysis shows that reliability models are optimistic if we do not consider security. We demonstrate how reliability models can be enhanced to take security issues into account and that the X.805 standard can be used to identify the security threats. Finally, the model shows themitigation in downtime by including intrusion-tolerance features in the product and network design. Consideration of security-caused downtimewill lead to increased focus on preventing security vulnerabilities that can lead to service outages and also allow service providers to save on maintenance costs. © 2006 Lucent Technologies Inc. [source]

Adaptive measurement-based traffic engineering in small differentiated services domains

Sven Krasser
In this paper, we propose a framework for measurement-based traffic engineering and connection admission control in small-differentiated services domains. The domain investigated is a wired radio access network based on the Internet protocol (IP). This framework is evaluated by simulation using the popular network simulator ns-2. The framework is adaptive to changes in the network load and supports multiple types of service. All traffic-engineering decisions are made by edge routers (ERs) at the rim of the network domain. Multiple disjoint paths are configured between those ERs. Network state information is gathered in two different fashions. We evaluate a scheme based on the states of the queues on each alternative path and a scheme based on end-to-end probe packet transmission characteristics on each alternative path. Both schemes are compared to a shortest path first (SPF) routing approach. Copyright © 2006 AEIT [source]

Call admission control for voice over IP

Huseyin Uzunalioglu
Abstract Voice over Internet protocol (VoIP) is a technology that enables the transmission of voice over an IP network. Recent years have witnessed heavy investment in this area in the commercial world. For VoIP to replace Public Switched Telephone Network (PSTN), it should provide voice quality comparable to circuit-switched PSTN networks. This paper addresses the mechanisms to guarantee VoIP quality of service (QoS). The focus is given to the call admission control, which blocks voice calls when the required resources are not available to guarantee the QoS for the call. We review call admission control approaches that can be applied to VoIP, and describe the advantages and disadvantages of each approach. In the second part of the paper, we present a measurement-based admission control scheme that achieves QoS in an efficient and scalable manner. The scheme uses voice traffic load measurements at each router link to compute link-level blocking policies for new call attempts. Then, these policies are translated into path-level blocking policies, which are applied to new call set-up requests. The performance of the scheme is presented for single and multiple-priority voice calls. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Satellite communications: the contribution of the 5th framework programme and future perspectives

Bernard Barani
Abstract The telecommunication sector is of key importance for the European economy. Digitization, secure broadband access and mobility are expected to shift an ever-growing proportion of the economy on line, thus creating new markets and business opportunities. With the eEurope 2002 and eEurope 2005 initiatives, the European Union has initiated a number of policy actions aiming at favouring the rapid introduction of innovative communication systems, services and applications. Research and development, as supported under the IST programme of the Union, is closely associated to the overall policy picture. The IST programme is notably instrumental in supporting, with a longer-term approach, key policy orientations such as the pervasive introduction of low cost broadband access, introduction of advanced mobile systems, or migration of networks towards the next generation of Internet protocol, IPv6. Satellite communication form an integral part of this diversified communication landscape, and has also been significantly supported under the 5th Framework Programme. Even if the problematic of the satcom industry are to some extent similar to those of the terrestrial players (e.g. catalysing take up of broadband and advanced mobile markets), the strategies followed by the satcom sector differ from those followed by the terrestrial players. This paper review the current technological approaches of the satcom industry, their relevance in the context of the policy goals of the Union, and how they have been supported under the IST programme. It also introduces briefly how co-ordination with ESA work has been achieved, and the perspectives for further support, notably under the now starting 6th Framework Programme. Copyright © 2004 John Wiley & Sons, Ltd. [source]

The effect of physical and link layers on IP QoS

Jeffrey H. Dunn
In the traditional Internet Engineering Task Force (IETF) network model, Internet protocol (IP) provided only an unreliable, best-effort delivery service. As a result, the effects of the physical and data-link layers on IP performance were ignored. In the current Internet service provider (ISP) environment, service-level agreements (SLA) require that IP-based services provide quality of service (QoS) guarantees. These guarantees (e.g., asynchronous transfer mode [ATM], connection admission control, and frame relay [FR] traffic policing) are often based on or enforced through physical and link-layer provisioning parameters. In this paper, we examine the effects of the ATM and FR physical and data-link layers and their interworking on IP performance. Specifically, we characterize the impact of ATM and FR impairments, traffic policing, and interworking on IP traffic. © 2003 Lucent Technologies Inc. [source]

Service control for next-generation applications in wireless IP multimedia networks

Lynell E. Cannell
Within the 3rd Generation Partnership Project (3GPP), the thrust of the session initiation protocol (SIP)-based Internet protocol (IP) multimedia subsystem (IMS) is envisaged to allow a swift progression towards the provision of multimedia applications for increasingly demanding end users. The paradigm of service programmability using open network application programming interfaces (APIs), with open service access (OSA) as its main exponent, is helping to drive this development together with the use of SIP. The focal point of this paper will be the multimedia services architecture in the IMS by providing details of the interaction of the IMS and the application servers in the form of the OSA gateway and the SIP application server. The paper aims to assess the value of the IMS service control (ISC) interface on application server interaction in the IMS. The paper will provide an OSA application use case, and will also present the presence server as an example of a SIP application server that fits in with the IMS. © 2003 Lucent Technologies Inc. [source]

Emerging uses of SIP in service provider networks

Guy J. Zenner
The session initiation protocol (SIP) has emerged as a viable protocol for providing numerous services within today's networks. SIP was closely modeled after http to make it an easily extensible protocol that could provide connectivity in new converged Internet protocol (IP) networks. The inherent extensibility of SIP has allowed SIP to be used in many ways not envisioned by its creators. What started as a simple protocol for setting up a media stream between two endpoints has since found numerous seemingly unrelated uses. With many solutions using SIP being proposed and implemented, it is often hard to determine how best to use SIP for a particular solution. The purpose of this paper is to give the reader a framework for categorizing various SIP capabilities through the concept of usage models and to help the reader understand the various ways SIP can be used in both evolutionary and revolutionary ways in real-world networks. This paper assumes the reader has a basic understanding of SIP and its inner workings. © 2003 Lucent Technologies Inc. [source]

Performance of soft phones and advances in associated technology

Christopher Chrin
Soft-phone technology for Internet protocol (IP) voice is growing in importance. However, soft phones exhibit poorer quality than public switched telephone network (PSTN) phones. A goal is to improve that quality, perhaps even to the point that the communication experience is better than with PSTN phones. This letter presents an analysis of soft-phone performance and describes acoustic echo cancellation and other technologies that improve soft-phone performance. © 2002 Lucent Technologies Inc. [source]

Modelling of wireless TCP for short-lived flows,

Sangheon Pack
Abstract The transmission control protocol (TCP) is one of the most important Internet protocols. It provides reliable transport services between two end-hosts. Since TCP performance affects overall network performance, many studies have been done to model TCP performance in the steady state. However, recent researches have shown that most TCP flows are short-lived. Therefore, it is more meaningful to model TCP performance in relation to the initial stage of short-lived flows. In addition, the next-generation Internet will be an unified all-IP network that includes both wireless and wired networks integrated together. In short, modelling short-lived TCP flows in wireless networks constitutes an important axis of research. In this paper, we propose simple wireless TCP models for short-lived flows that extend the existing analytical model proposed in [IEEE Commun. Lett. 2002; 6(2):85,88]. In terms of wireless TCP, we categorized wireless TCP schemes into three types: end-to-end scheme, split connection scheme, and local retransmission scheme, which is similar to the classification proposed in [IEEE/ACM Trans. Networking 1997; 756,769]. To validate the proposed models, we performed ns-2 simulations. The average differences between the session completion time calculated using the proposed model and the simulation result for three schemes are less than 9, 16, and 7 ms, respectively. Consequently, the proposed model provides a satisfactory means of modelling the TCP performance of short-lived wireless TCP flows. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Secure parallel file distribution through a streaming worm network

Michael J. Sheehan
This paper introduces the novel concept of streaming worms and applies the concept to secure parallel file transfer. A streaming worm (sworm) is a powerful class of software that can replicate itself as well as a chunk of arbitrary payload code on a predetermined set of nodes in a network very quickly, while streaming data between all of the nodes in parallel. By harnessing the parallelism and scalability of sworms in a file distribution application, large gigabyte files can be efficiently and securely distributed to a large number of nodes over a Transmission Control Protocol/Internet Protocol (TCP/IP) network without congesting the network. But unlike traditional file transfer tools such as File Transfer Protocol (FTP), remote copy (RCP), or secure copy (SCP), the total sworm transfer time is relatively independent of the number of target nodes for large files. As such, this method of parallel file distribution is particularly useful when a large array or cluster of similar computers has to be quickly updated with a large amount of identical software or data. © 2007 Alcatel-Lucent. [source]

Robotic pyeloplasty using internet protocol and satellite network-based telesurgery

C. Y. Nguan
Abstract Background In North America, the urological community has embraced surgical robotic technology in the performance of complex laparoscopic surgery. The performance of complex long-distance telesurgery requires further investigation prior to clinical application. Methods The feasibility of laparoscopic robot-assisted pyeloplasty in a porcine model was assessed using the Zeus robot and the internet protocol virtual private network (IP-VPNe) and satellite links. Eighteen pyeloplasty procedures were performed, using real-time, IP-VPNe and satellite network connection (six of each). Network and objective operative data were collected. Results Despite network delays and jitter, it was feasible to perform the pyeloplasty procedure without significant detriment in operative time or surgical results compared with real-time surgery. Conclusion The completion of complex tasks such as robotic pyeloplasty is feasible using both land-line and satellite telesurgery. However, the clinical relevance of telesurgery requires further assessment. Copyright © 2008 John Wiley & Sons, Ltd. [source]

xBCI: A Generic Platform for Development of an Online BCI System

I Putu Susila Non-member
Abstract A generic platform for realizing an online brain,computer interface (BCI) named xBCI was developed. The platform consists of several functional modules (components), such as data acquisition, storage, mathematical operations, signal processing, network communication, data visualization, experiment control, and real-time feedback presentation. Users can easily build their own BCI systems by combining the components on a graphical-user-interface (GUI) based diagram editor. They can also extend the platform by adding components as plug-ins or by creating components using a scripting language. The platform works on multiple operating systems and supports parallel (multi-threaded) data processing and data transfer to other PCs through a network transmission control protocol/internet protocol or user datagram protocol (TCP/IP or UDP). A BCI system based on motor imagery and a steady-state visual evoked potential (SSVEP) based BCI system were constructed and tested on the platform. The results show that the platform is able to process multichannel brain signals in real time. The platform provides users with an easy-to-use system development tool and reduces the time needed to develop a BCI system. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]