717 research outputs found
SPAD: a distributed middleware architecture for QoS enhanced alternate path discovery
In the next generation Internet, the network will evolve from a plain communication medium into one that provides endless services to the users. These services will be composed of multiple cooperative distributed application elements. We name these services overlay applications. The cooperative application elements within an overlay application will build a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS experienced on the communication paths of the corresponding overlay association. In this paper, we present SPAD (Super-Peer Alternate path Discovery), a distributed middleware architecture that aims at providing enhanced QoS between end-points within an overlay association. To achieve this goal, SPAD provides a complete scheme to discover and utilize composite alternate end-to end paths with better QoS than the path given by the default IP routing mechanisms
Distributed discovery and management of alternate paths with enhanced quality of service in the internet
La convergence de rĂ©centes avancĂ©es technologiques permet l'Ă©mergence de nouveaux environnements informatiques pervasifs, dans lesquels des terminaux en rĂ©seaux coopĂšrent et communiquent de maniĂšre transparente pour les utilisateurs. Ces utilisateurs demandent des fonctionalitĂ©s de plus en plus avancĂ©es de la part de ces terminaux. Etant donnĂ©es les limites intrinsĂšques des terminaux mobiles, ces fonctionalitĂ©s, au lieu d'ĂȘtre directement implĂ©mentĂ©es dans les terminaux, sont appelĂ©es Ă ĂȘtre fournies par des fournisseurs de services situĂ©s Ă la pĂ©riphĂ©rie du rĂ©seau. Ce derniers devient alors une source illimitĂ©e de services, et non plus seulement un medium de communication. Ces services, ou applications d'overlays, sont formĂ©s de plusieurs Ă©lĂ©ments applicatifs distribuĂ©s qui coopĂšrent et communiquent entre eux via un rĂ©seau de recouvrement dynamique particulier, une association d'overlay. La QualitĂ© de Service (QdS) perçue par les utilisateurs d'une application d'overlay dĂ©pend de la QdS existant au niveau des chemins de communications qui forment l'association d'overlay correspondante. Cette thĂšse montre qu'il est possible de fournir de la QdS Ă une application d'overlay en utilisant des chemins Internet alternatifs, rĂ©sultant de la composition de chemins distincts. De plus, cette thĂšse montre Ă©galement qu'il est possible de dĂ©couvrir, sĂ©lectionner, et composer d'une maniĂšre distribuĂ©e ces chemins Ă©lĂ©mentaires, au sein d'une communautĂ© comprenant un nombre important d'entitĂ©s paires (telles que les prĂ©cĂ©dents fournisseurs de services). Les principales contributions de cette thĂšse sont : i) une description et une analyse des caractĂ©ristiques de QdS de ces chemins alternatifs composĂ©s, ii) une architecture originale appelĂ©e SPAD (Super-Peer based Alternate path Discovery), qui permet la dĂ©couverte et la sĂ©lection de maniĂšre distribuĂ©e de ces chemins alternatifs. SPAD est un systĂšme complĂštement dĂ©centralisĂ©, qui peut ĂȘtre facilement et incrĂ©mentalement dĂ©ployĂ© sur l'Internet actuel. Il permet aux utilisateurs situĂ©s Ă la pĂ©riphĂ©rie du rĂ©seau de dĂ©couvrir et d'utiliser directement des chemins alternatifs. ABSTRACT : The convergence of recent technology advances opens the way to new ubiquitous environments, where network-enabled devices collectively form invisible pervasive computing and networking environments around the users. These users increasingly require extensive applications and capabilities from these devices. Recent approaches propose that cooperating service providers, at the edge of the network, offer these required capabilities (i.e services), instead of having them directly provided by the devices. Thus, the network evolves from a plain communication medium into an endless source of services. Such a service, namely an overlay application, is composed of multiple distributed application elements, which cooperate via a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS on the communication paths of the corresponding overlay association. This thesis asserts and shows that it is possible to provide QoS to an overlay application by using alternate Internet paths resulting from the compositions of independent consecutive paths. Moreover, this thesis also demonstrates that it is possible to discover, select and compose these independent paths in a distributed manner within an community comprising a limited large number of autonomous cooperating peers, such as the fore-mentioned service providers. Thus, the main contributions of this thesis are i) a comprehensive description and QoS characteristic analysis of these composite alternate paths, and ii) an original architecture, termed SPAD (Super-Peer based Alternate path Discovery), which allows the discovery and selection of these alternate paths in a distributed manner. SPAD is a fully distributed system with no single point of failure, which can be easily and incrementally deployed on the current Internet. It empowers the end-users at the edge of the network, allowing them to directly discover and utilize alternate paths
De-ossifying the Internet Transport Layer : A Survey and Future Perspectives
ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful suggestions and comments.Peer reviewedPublisher PD
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Design of interface selection protocols for multi-homed wireless networks
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 10 December 2010.The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of âunreachable zonesâ, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios
Qos Provisioning for Energy Efficiency in Mobile Ad-Hoc Network
In mobile ad-hoc networks Quality of Service QoS of a multicast routing protocol is one of the most key performance metrics Slotconditions and network topology frequently change Topology dynamic and in order to achieve a certain level of QoS complexalgorithms and protocols are needed Network graph conditionsare neglected during the design of aexisting multicast protocol However vulnerability against network graph errors can severely affect theperformance of a multicast protocol To address this here the author proposesanenergy efficient network graph pre-processing approach to enable traffic engineering and enhance the performance of energy efficiency in terms of network efficiency by QoSprovisioning to cater the multicast routing issue in MANETS In this approach prioritized admission control PAC scheme is implemented to improvise D2D Device to Device communications into cellular network to overcome the limitations of MANET
Exploiting the power of multiplicity: a holistic survey of network-layer multipath
The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work
IP and ATM integration: A New paradigm in multi-service internetworking
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
Quality of service routing for real-time traffic
Imperial Users onl
IEEE 802.11s Mesh Deterministic Access : Design and analysis
IEEE 802.11s is a draft IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create an ad-hoc network.
It includes some mesh-specific optional MAC enhancements like Mesh Deterministic Access, Common Channel Framework, Intra-mesh Congestion Control and Power Management.
Mesh Deterministic Access (MDA) is an access method that allows MPs to access the channel at selected times (called MDAOPs) with lower contention than would otherwise be possible.
In this work we study Mesh Deterministic Access (MDA) feature. Specifically: we implement 802.11s in ns-2 simulator and evaluate performance comparing results with those obtained with DCF.
We also propose an improvement called Dynamic Relocation.
Dynamic Relocation permits to overcome MDA limits by reallocating MDAOPs basing on statistics collected during transmission times.
The effectiveness of MDA improved with Dynamic Relocation in a scenario with realistic traffic is then confirmed via a simulation analysis
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