2,696 research outputs found

    Future benefits and applications of intelligent on-board processing to VSAT services

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    The trends and roles of VSAT services in the year 2010 time frame are examined based on an overall network and service model for that period. An estimate of the VSAT traffic is then made and the service and general network requirements are identified. In order to accommodate these traffic needs, four satellite VSAT architectures based on the use of fixed or scanning multibeam antennas in conjunction with IF switching or onboard regeneration and baseband processing are suggested. The performance of each of these architectures is assessed and the key enabling technologies are identified

    Convergence, digitisation and new technologies: Toward the next generation network

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    https://doi.org/10.23962/10539/19838https://doi.org/10.23962/10539/1983

    IP-based virtual private networks and proportional quality of service differentiation

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    IP-based virtual private networks (VPNs) have the potential of delivering cost-effective, secure, and private network-like services. Having surveyed current enabling techniques, an overall picture of IP VPN implementations is presented. In order to provision the equivalent quality of service (QoS) of legacy connection-oriented layer 2 VPNs (e.g., Frame Relay and ATM), IP VPNs have to overcome the intrinsically best effort characteristics of the Internet. Subsequently, a hierarchical QoS guarantee framework for IP VPNs is proposed, stitching together development progresses from recent research and engineering work. To differentiate IP VPN QoS, the proportional QoS differentiation model, whose QoS specification granularity compromises that of IntServ and Diffserv, emerges as a potential solution. The investigation of its claimed capability of providing the predictable and controllable QoS differentiation is then conducted. With respect to the loss rate differentiation, the packet shortage phenomenon shown in two classical proportional loss rate (PLR) dropping schemes is studied. On the pursuit of a feasible solution, the potential of compromising the system resource, that is, the buffer, is ruled out; instead, an enhanced debt-aware mechanism is suggested to relieve the negative effects of packet shortage. Simulation results show that debt-aware partially curbs the biased loss rate ratios, and improves the queueing delay performance as well. With respect to the delay differentiation, the dynamic behavior of the average delay difference between successive classes is first analyzed, aiming to gain insights of system dynamics. Then, two classical delay differentiation mechanisms, that is,proportional average delay (PAD) and waiting time priority (WTP), are simulated and discussed. Based on observations on their differentiation performances over both short and long time periods, a combined delay differentiation (CDD) scheme is introduced. Simulations are utilized to validate this method. Both loss and delay differentiations are based on a series of differentiation parameters. Though previous work on the selection of delay differentiation parameters has been presented, that of loss differentiation parameters mostly relied on network operators\u27 experience. A quantitative guideline, based on the principles of queueing and optimization, is then proposed to compute loss differentiation parameters. Aside from analysis, the new approach is substantiated by numerical results

    Performance evaluation of HIP-based network security solutions

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    Abstract. Host Identity Protocol (HIP) is a networking technology that systematically separates the identifier and locator roles of IP addresses and introduces a Host Identity (HI) name space based on a public key security infrastructure. This modification offers a series of benefits such as mobility, multi-homing, end-to-end security, signaling, control/data plane separation, firewall security, e.t.c. Although HIP has not yet been sufficiently applied in mainstream communication networks, industry experts foresee its potential as an integral part of next generation networks. HIP can be used in various HIP-aware applications as well as in traditional IP-address-based applications and networking technologies, taking middle boxes into account. One of such applications is in Virtual Private LAN Service (VPLS), VPLS is a widely used method of providing Ethernet-based Virtual Private Network that supports the connection of geographically separated sites into a single bridged domain over an IP/MPLS network. The popularity of VPLS among commercial and defense organizations underscores the need for robust security features to protect both data and control information. After investigating the different approaches to HIP, a real world testbed is implemented. Two experiment scenarios were evaluated, one is performed on two open source Linux-based HIP implementations (HIPL and OpenHIP) and the other on two sets of enterprise equipment from two different companies (Tempered Networks and Byres Security). To account for a heterogeneous mix of network types, the Open source HIP implementations were evaluated on different network environments, namely Local Area Network (LAN), Wireless LAN (WLAN), and Wide Area Network (WAN). Each scenario is tested and evaluated for performance in terms of throughput, latency, and jitter. The measurement results confirmed the assumption that no single solution is optimal in all considered aspects and scenarios. For instance, in the open source implementations, the performance penalty of security on TCP throughput for WLAN scenario is less in HIPL than in OpenHIP, while for WAN scenario the reverse is the case. A similar outcome is observed for the UDP throughput. However, on latency, HIPL showed lower latency for all three network test scenarios. For the legacy equipment experiment, the penalty of security on TCP throughput is about 19% compared with the non-secure scenario while latency is increased by about 87%. This work therefore provides viable information for researchers and decision makers on the optimal solution to securing their VPNs based on the application scenarios and the potential performance penalties that come with each approach.HIP-pohjaisten tietoliikenneverkkojen turvallisuusratkaisujen suorituskyvyn arviointi. Tiivistelmä. Koneen identiteettiprotokolla (HIP, Host Identity Protocol) on tietoliikenneverkkoteknologia, joka käyttää erillistä kerrosta kuljetusprotokollan ja Internet-protokollan (IP) välissä TCP/IP-protokollapinossa. HIP erottaa systemaattisesti IP-osoitteen verkko- ja laite-osat, sekä käyttää koneen identiteetti (HI) -osaa perustuen julkisen avainnuksen turvallisuusrakenteeseen. Tämän hyötyjä ovat esimerkiksi mobiliteetti, moniliittyminen, päästä päähän (end-to-end) turvallisuus, kontrolli-informaation ja datan erottelu, kohtaaminen, osoitteenmuutos sekä palomuurin turvallisuus. Teollisuudessa HIP-protokolla nähdään osana seuraavan sukupolven tietoliikenneverkkoja, vaikka se ei vielä olekaan yleistynyt laajaan kaupalliseen käyttöön. HIP–protokollaa voidaan käyttää paitsi erilaisissa HIP-tietoisissa, myös perinteisissä IP-osoitteeseen perustuvissa sovelluksissa ja verkkoteknologioissa. Eräs tällainen sovellus on virtuaalinen LAN-erillisverkko (VPLS), joka on laajasti käytössä oleva menetelmä Ethernet-pohjaisen, erillisten yksikköjen ja yhden sillan välistä yhteyttä tukevan, virtuaalisen erillisverkon luomiseen IP/MPLS-verkon yli. VPLS:n yleisyys sekä kaupallisissa- että puolustusorganisaatioissa korostaa vastustuskykyisten turvallisuusominaisuuksien tarpeellisuutta tiedon ja kontrolliinformaation suojauksessa. Tässä työssä tutkitaan aluksi HIP-protokollan erilaisia lähestymistapoja. Teoreettisen tarkastelun jälkeen käytännön testejä suoritetaan itse rakennetulla testipenkillä. Tarkasteltavat skenaariot ovat verrata Linux-pohjaisia avoimen lähdekoodin HIP-implementaatioita (HIPL ja OpenHIP) sekä verrata kahden eri valmistajan laitteita (Tempered Networks ja Byres Security). HIP-implementaatiot arvioidaan eri verkkoympäristöissä, jota ovat LAN, WLAN sekä WAN. Kaikki testatut tapaukset arvioidaan tiedonsiirtonopeuden, sen vaihtelun (jitter) sekä latenssin perusteella. Mittaustulokset osoittavat, että sama ratkaisu ei ole optimaalinen kaikissa tarkastelluissa tapauksissa. Esimerkiksi WLAN-verkkoa käytettäessä turvallisuuden aiheuttama häviö tiedonsiirtonopeudessa on HIPL:n tapauksessa OpenHIP:iä pirnempi, kun taas WAN-verkon tapauksessa tilanne on toisinpäin. Samanlaista käyttäytymistä havaitaan myös UDP-tiedonsiirtonopeudessa. HIPL antaa kuitenkin pienimmän latenssin kaikissa testiskenaarioissa. Eri valmistajien laitteita vertailtaessa huomataan, että TCP-tiedonsiirtonopeus huononee 19 ja latenssi 87 prosenttia verrattuna tapaukseen, jossa turvallisuusratkaisua ei käytetä. Näin ollen tämän työn tuottama tärkeä tieto voi auttaa alan toimijoita optimaalisen verkkoturvallisuusratkaisun löytämisessä VPN-pohjaisiin sovelluksiin

    Analysis Effectiveness VOIP Over MPLS-IPVPN For State Government Network

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    The performance of the Voice over IP (VoIP) protocol is of interest when planning for public access. The technologies, which work well for limited use often, fail to scale-up to the user requirements. High-quality VoIP services are required as for the Internet communications to be an alternative towards Public Switched Telephone Network (PSTN). The deployment of VoIP in the Internet network does not promise a good Quality of Service (QoS), since Internet is a kind of best-effort networks. The privacy consideration is also of importance when provisioning voice services on the Internet; particularly from the business use perspective. A full study, which comes up with a definitive set of recommendations would require considerable work over a substantial period of time, however some information on the performance may be obtained by reenacting the most commonly occurring conditions in the lab to ascertain the sensitivity of the VoIP to its key QoS parameters. The aim of this project is to analyze effective VOIP technique and analyze the performance of VoIP communications by observing the QoS parameters variation with respect to the some of the pertinent communication aspects on State Government Network. The aspect chosen in this regard comprise the call signaling protocols, the networking environments, and VPN protocols. Some similar studies have also been used as a comparative measurement towards the results obtained from this research

    VOIP adoption and bussiness prospective in Bangladeh

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    This thesis report is submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Computer Science and Engineering, 2007.Cataloged from PDF version of thesis report.Includes bibliographical references (page 30).Voice over Internet protocol - VoIP, or IP telephony is a technology by which the routing of voice communications are done through Internet or any other Internet Protocol (IP) based networks. Here the voice data is transmitted over a general purpose packet-switched network instead of dedicated traditional circuit-switched voice transmission lines. Voice Over Internet Protocol (VoIP) is a telephony technology used to transmit ordinary telephone calls over the Internet. VoIP takes analogue audio signals and turns them into digital signals (packets) that are transmitted using Internet Protocol (IP) networks. VoIP’s advantages include low cost, flexibility, and mobility. Conversely, VoIP’s disadvantages include sound quality such as latency (delay), jitter, and packet loss. VoIP has a number of cultural, social, and regulatory impacts that solution providers must consider when marketing their services.Our target is to learn the basics of VoIP, to focus on the current problems of VoIP, to find out the solutions, to Setup a VoIP business.Md. RuhanuzzamanNahid MahmudB. Computer Science and Engineerin

    IP and ATM integration: A New paradigm in multi-service internetworking

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    ATM is a widespread technology adopted by many to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia communication together with the increasing massive utilization of IP-based applications urgently require redesign of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex top-down architecture is unlikely to be applicable. Instead, an approach based on finding out the best match between realistic service requirements and the pragmatic, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, we look at both IP and ATM internetworking in order to investigating a few of the most crucial topics/ issues related to the IP and ATM integration perspective. This research would also address various means of internetworking the Internet Protocol (IP) and Asynchronous Transfer Mode (ATM) with an objective of identifying the best possible means of delivering Quality of Service (QoS) requirements for multi-service applications, exploiting the meritorious features that IP and ATM have to offer. Although IP and ATM often have been viewed as competitors, their complementary strengths and limitations from a natural alliance that combines the best aspects of both the technologies. For instance, one limitation of ATM networks has been the relatively large gap between the speed of the network paths and the control operations needed to configure those data paths to meet changing user needs. IP\u27s greatest strength, on the other hand, is the inherent flexibility and its capacity to adapt rapidly to changing conditions. These complementary strengths and limitations make it natural to combine IP with ATM to obtain the best that each has to offer. Over time many models and architectures have evolved for IP/ATM internetworking and they have impacted the fundamental thinking in internetworking IP and ATM. These technologies, architectures, models and implementations will be reviewed in greater detail in addressing possible issues in integrating these architectures s in a multi-service, enterprise network. The objective being to make recommendations as to the best means of interworking the two in exploiting the salient features of one another to provide a faster, reliable, scalable, robust, QoS aware network in the most economical manner. How IP will be carried over ATM when a commercial worldwide ATM network is deployed is not addressed and the details of such a network still remain in a state of flux to specify anything concrete. Our research findings culminated with a strong recommendation that the best model to adopt, in light of the impending integrated service requirements of future multi-service environments, is an ATM core with IP at the edges to realize the best of both technologies in delivering QoS guarantees in a seamless manner to any node in the enterprise

    Cost-effective Information and Communication Technology (ICT) infrastructure for Tanziania

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    The research conducted an Information and Communication Technology (ICT) field survey, the results revealed that Tanzania is still lagging behind in the ICT sector due to the lack of an internationally connected terrestrial ICT infrastructure; Internet connectivity to the rest of the world is via expensive satellite links, thus leaving the majority of the population unable to access the Internet services due to its high cost. Therefore, an ICT backbone infrastructure is designed that exploits optical DWDM network technology, which un-locks bandwidth bottlenecks and provides higher capacity which will provide ICT services such as Internet, voice, videos and other multimedia interactions at an affordable cost to the majority of the people who live in the urban and rural areas of Tanzania. The research analyses and compares the performance, and system impairments, in a DWDM system at data transmission rates of 2.5 Gb/s and 10 Gb/s per wavelength channel. The simulation results show that a data transmission rate of 2.5 Gb/s can be successfully transmitted over a greater distance than 10 Gb/s with minimum system impairments. Also operating at the lower data rate delivers a good system performance for the required ICT services. A forty-channel DWDM system will provide a bandwidth of 100 Gb/s. A cost analysis demonstrates the economic worth of incorporating existing optical fibre installations into an optical DWDM network for the creation of an affordable ICT backbone infrastructure; this approach is compared with building a completely new optical fibre DWDM network or a SONET/SDH network. The results show that the ICT backbone infrastructure built with existing SSMF DWDM network technology is a good investment, in terms of profitability, even if the Internet charges are reduced to half current rates. The case for building a completely new optical fibre DWDM network or a SONET/SDH network is difficult to justify using current financial data

    Loop detection and prevention mechanism in multiprotocol label switching

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    The extended color thread algorithm is based on running a thread hop by hop before the labels are distributed inside a MPLS Cloud Since the path for the data packets is set beforehand, the loop formation occurs at the control path. The shortest paths between selected source and destination have been calculated using Dijkstra\u27s shortest path algorithm and threads are allowed to extend through the routers. With the passage of each next hop, a distributed procedure is executed within the thread, generating a unique color at nodes. This keeps a track on router\u27s control path and at the same time ensures that no loop formation occurs. In loop prevention mode, a router transmits a label mapping, when it rewinds the thread for that particular LSP. Likewise, if a router operates in loop detection mode, it returns a label-mapping message without a thread object, after receiving a colored thread. The scheme is a loop prevention scheme, thus, ensuring loop detection and loop mitigation. The same algorithm is then extended to a proposed MPLS environment with global label space. (Abstract shortened by UMI.)

    Designing and optimization of VOIP PBX infrastructure

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    In the recent decade, communication has stirred from the old wired medium such as public switched telephone network (PSTN) to the Internet. Present, Voice over Internet Protocol (VoIP) Technology used for communication on internet by means of packet switching technique. Several years ago, an internet protocol (IP) based organism was launched, which is known as Private Branch Exchange "PBX", as a substitute of common PSTN systems. For free communication, probably you must have to be pleased with starting of domestic calls. Although, fairly in few cases, VoIP services can considerably condense our periodical phone bills. For instance, if someone makes frequent global phone calls, VoIP talk service is the actual savings treat which cannot achieve by using regular switched phone. VoIP talk services strength help to trim down your phone bills if you deal with a lot of long-distance (international) and as well as domestic phone calls. However, with the VoIP success, threats and challenges also stay behind. In this dissertation, by penetration testing one will know that how to find network vulnerabilities how to attack them to exploit the network for unhealthy activities and also will know about some security techniques to secure a network. And the results will be achieved by penetration testing will indicate of proven of artefact and would be helpful to enhance the level of network security to build a more secure network in future
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