The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

A.e. Kamal - One of the best experts on this subject based on the ideXlab platform.

  • Exploiting Multichannel Diversity for Cooperative Multicast in Cognitive Radio Mesh Networks
    IEEE ACM Transactions on Networking, 2014
    Co-Authors: Hisham M. Almasaeid, A.e. Kamal
    Abstract:

    Cognitive radio networks (CRNs) have emerged as a promising, yet challenging, solution to enhance spectrum utilization, thanks to the technology of cognitive radios. A well-known property of CRNs is the potential heterogeneity in channel availability among secondary users. Therefore, multicast throughput in CRNs may suffer from significant degradation because of this property since a link-level broadcast of a frame may only reach a small subSet of Destinations that are able to receive on the same channel. This may necessitate multiple sequential transmissions of the same frame by the source on different channels to guarantee delivery to all receivers in the Destination Set. In case of high data generation rate, delivery delay will be high due to the repeated transmissions by the source. In this paper, we propose an assistance strategy to reduce the effect of the channel heterogeneity property on the multicast throughput in cognitive radio wireless mesh networks (CR-WMNs). This assistance strategy is composed of two main activities: first, allowing multicast receivers to assist the source in delivering the data, and second, allowing the transmission of coded packets so that multicast receivers belonging to different multicast groups can decode and extract their data concurrently. Results show that the proposed assistance paradigm reduces multicast time and increases throughput significantly.

  • Design and provisioning of WDM networks with multicast traffic grooming
    IEEE Journal on Selected Areas in Communications, 2006
    Co-Authors: R. Ul-mustafa, A.e. Kamal
    Abstract:

    In this paper we consider the optimal design and provisioning of WDM networks for the grooming of multicast subwavelength traffic. We develop a unified framework for the optimal provisioning of different practical scenarios of multicast traffic grooming. We also introduce heuristic solutions. Optimal solutions are designed by exploiting the specifies of the problems to formulate Mixed Integer Linear Programs (MILPs). Specifically, we solve the generic multicast problem in which, given a Set of multicast sessions and all Destination nodes of a multicast session requiring the same amount of traffic, all demands need to be accommodated. The objective is to minimize the network cost by minimizing the number of higher layer electronic equipment and, simultaneously, minimizing the total number of wavelengths used. We also solve two interesting and practical variants of the traditional multicast problem, namely, multicasting with partial Destination Set reachability and multicasting with traffic thinning. For both variants, we also provide optimal as well as heuristic solutions. Also, the paper presents a number of examples based on the exact and heuristic approaches

  • On the grooming of multicast traffic in WDM networks
    Proceedings. ISCC 2004. Ninth International Symposium on Computers And Communications (IEEE Cat. No.04TH8769), 2004
    Co-Authors: R. Ul-mustafa, A.e. Kamal
    Abstract:

    In This work we consider the optimal dimensioning of optical networks for multicast traffic grooming problems on WDM networks under two practical scenarios. In both cases, for each multicast session the Destination Set consists of two disjoint subSets. In the first scenario only one subSet of each multicast session must be accommodated while the other subSet can only be accommodated if this results in no additional cost. In the second case, both subSets of each multicast session must be accommodated. However, each subSet has different bandwidth requirements. We develop optimal and heuristic solutions for both the cases.

  • ISCC - On the grooming of multicast traffic in WDM networks
    Proceedings. ISCC 2004. Ninth International Symposium on Computers And Communications (IEEE Cat. No.04TH8769), 2004
    Co-Authors: R. Ul-mustafa, A.e. Kamal
    Abstract:

    In This work we consider the optimal dimensioning of optical networks for multicast traffic grooming problems on WDM networks under two practical scenarios. In both cases, for each multicast session the Destination Set consists of two disjoint subSets. In the first scenario only one subSet of each multicast session must be accommodated while the other subSet can only be accommodated if this results in no additional cost. In the second case, both subSets of each multicast session must be accommodated. However, each subSet has different bandwidth requirements. We develop optimal and heuristic solutions for both the cases.

Panagiotis Tsiotras - One of the best experts on this subject based on the ideXlab platform.

  • CDC - The Markov-Dubins problem in the presence of a stochastic drift field
    2012 IEEE 51st IEEE Conference on Decision and Control (CDC), 2012
    Co-Authors: Ross P. Anderson, Efstathios Bakolas, Dejan Milutinovic, Panagiotis Tsiotras
    Abstract:

    We consider the problem of navigating a small Dubins-type aerial or marine vehicle to a prescribed Destination Set in minimum expected time and in the presence of a stochastic drift field induced by local winds or currents. First, we present a deterministic control law that is independent of the local winds/currents and their statistics. Next, by employing numerical techniques from stochastic optimal control, we compute an optimal feedback control strategy that incorporates the stochastic variation in the wind when driving the Dubins vehicle to its Destination Set in minimum expected time. Our analyses and simulations offer a side-by-side comparison of the optimal deterministic and stochastic optimal feedback control laws for this problem, and they illustrate that the deterministic control can, in many cases, capture the salient features of structure of the stochastic optimal feedback control.

  • The Markov-Dubins problem in the presence of a stochastic drift field
    2012 IEEE 51st IEEE Conference on Decision and Control (CDC), 2012
    Co-Authors: Ross P. Anderson, Efstathios Bakolas, Dejan Milutinović, Panagiotis Tsiotras
    Abstract:

    We consider the problem of navigating a small Dubins-type aerial or marine vehicle to a prescribed Destination Set in minimum expected time and in the presence of a stochastic drift field induced by local winds or currents. First, we present a deterministic control law that is independent of the local winds/currents and their statistics. Next, by employing numerical techniques from stochastic optimal control, we compute an optimal feedback control strategy that incorporates the stochastic variation in the wind when driving the Dubins vehicle to its Destination Set in minimum expected time. Our analyses and simulations offer a side-by-side comparison of the optimal deterministic and stochastic optimal feedback control laws for this problem, and they illustrate that the deterministic control can, in many cases, capture the salient features of structure of the stochastic optimal feedback control.

Vinod M. Vokkarane - One of the best experts on this subject based on the ideXlab platform.

  • Analytical Blocking Model for Generalized Light-tree in Optical WDM Networks
    2018 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN), 2018
    Co-Authors: Vinod M. Vokkarane
    Abstract:

    The manycast communication paradigm is becoming increasingly important in today's optical networks, wherein connection requests from a source node can be routed to a subSet of a candidate Destination Set. This flexibility in choosing different Destinations from a larger candidate Destination Set helps improve the network performance. In this paper, we develop a new analytical model to compute the network-wide blocking performance for generalized manycast routing and wavelength assignment (MRWA) in optical wavelength division multiplexed (WDM) networks. Specifically, we calculate the request blocking on full-wavelength convertible optical networks based on Markov chains and conditional probability analysis. Performance results show that our model is accurate and is verified by extensive simulation results.

  • LANMAN - Analytical Blocking Model for Generalized Light-tree in Optical WDM Networks
    2018 IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN), 2018
    Co-Authors: Vinod M. Vokkarane
    Abstract:

    The manycast communication paradigm is becoming increasingly important in today’s optical networks, wherein connection requests from a source node can be routed to a subSet of a candidate Destination Set. This flexibility in choosing different Destinations from a larger candidate Destination Set helps improve the network performance. In this paper, we develop a new analytical model to compute the network-wide blocking performance for generalized manycast routing and wavelength assignment (MRWA) in optical wavelength division multiplexed (WDM) networks. Specifically, we calculate the request blocking on full-wavelength convertible optical networks based on Markov chains and conditional probability analysis. Performance results show that our model is accurate and is verified by extensive simulation results.

  • Generalized Survivability Models for Many-to-Many Communication
    2018 International Conference on Computing Networking and Communications (ICNC), 2018
    Co-Authors: Dylan A. P. Davis, Vinod M. Vokkarane
    Abstract:

    Network resources are imperfect and vulnerable to failure from a wide variety of sources. Current survivability models guarantee protection against these failures, but at the cost of inflexibility in terms of applicability to different routing standards and in how many additional resources are consumed to provide protection against those failures. We propose several generalized models that utilize the flexibility of many-to-many communication which, when implemented, can solve a large number of existing survivability and routing problems. A key component of these models is a flexible source and Destination Set with which communication between any number of endpoints can be established. These connections can be adjusted through changes to a flexible failure Set to have either end-to-end or partial protection against the failures of both nodes and links. With these models, a framework can be built to tackle the complex survivability problems of an evolving Internet.

  • ICNC - Generalized Survivability Models for Many-to-Many Communication
    2018 International Conference on Computing Networking and Communications (ICNC), 2018
    Co-Authors: Dylan A. P. Davis, Vinod M. Vokkarane
    Abstract:

    Network resources are imperfect and vulnerable to failure from a wide variety of sources. Current survivability models guarantee protection against these failures, but at the cost of inflexibility in terms of applicability to different routing standards and in how many additional resources are consumed to provide protection against those failures. We propose several generalized models that utilize the flexibility of many-to-many communication which, when implemented, can solve a large number of existing survivability and routing problems. A key component of these models is a flexible source and Destination Set with which communication between any number of endpoints can be established. These connections can be adjusted through changes to a flexible failure Set to have either end-to-end or partial protection against the failures of both nodes and links. With these models, a framework can be built to tackle the complex survivability problems of an evolving Internet. 11This work has been supported by the Department of Energy (DOE) PROPER project under grant DE-SC0012115TDD and by the National Science Foundation (NSF) CARGONET project under grant CNS-1406370.

  • Slotted advance reservation for multicast-incapable optical wavelength division multiplexing networks
    IEEE OSA Journal of Optical Communications and Networking, 2014
    Co-Authors: Arush Gadkar, Tim Entel, Jeremy M. Plante, Vinod M. Vokkarane
    Abstract:

    In this paper we investigate techniques for provisioning advance reservation (AR) multicast requests in multicast-incapable (MI) networks, which lack the ability to split an incoming signal to multiple output ports, without performing an O-E-O conversion. AR traffic consists of connection requests that arrive and reserve network resources at some time before they need them to ensure better qualityof service than on-demand requests would receive. The traditional approach of providing multicast support in MI networks is to use an overlay approach in which a Set of lightpaths is established from the source to each multicast Destination member independently. This approach is wasteful of wavelength resources, particularly as the multicast Destination Set grows. We propose two alternative overlay approaches that take advantage of multiple-hop overlay-tree structures to limit the consumption of wavelengths in the network. We investigate static traffic scenarios on various network topologies and develop integer linear programs (ILPs) to optimally solve all three of the overlay-tree problems presented in this work with the goal of minimizing the total number of wavelengths required to service a multicast request Set. We also present efficient heuristics that build and select overlay-trees that lower dynamic connection blocking and wavelength consumption. We compare the heuristics to the optimal ILPs on a small-scale network, and then further evaluate the heuristics on several large-scale topologies. In all scenarios, we are able to conclude that by sacrificing a minimization of O-E-O conversions, our more flexible overlay approaches, called drop at member node (MI-DMN) and dropatany node (MI-DAN), are superiorinterms of resource usage when compared with the traditional naive approach. Further dynamic traffic evaluations reveal that blocking may be lowered over the naive approach by more thantwoordersofmagnitudeatlowtomedium traffic loads.

M.h. Ammar - One of the best experts on this subject based on the ideXlab platform.

  • INFOCOM - On the use of Destination Set grouping to improve inter-receiver fairness for multicast ABR sessions
    Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Socie, 2000
    Co-Authors: Tianji Jiang, M.h. Ammar, E.w. Zegura
    Abstract:

    Multicast applications can involve a large number of receivers with heterogeneous data reception capabilities. In a traditional single-rate multicast session, the transmission rate at the source is chosen to match the lowest capacity path to a receiver in the session. This can cause an under-utilization of higher capacity paths to other receivers. We have previously defined an inter-receiver fairness measure in order to quantify the effect of this underutilization. We also developed protocols that use this measure to guide the choice of the source rate for a single-rate session. In this paper we design and develop a multi-rate protocol in the context of an ATM ABR service to achieve better inter-receiver fairness for a multicast session. The multi-rate protocol we investigate is based on the use of Destination Set grouping (DSG) where the Set of receivers in a multicast session is partitioned into disjoint subgroups. The transmitter carries a separate conversation with each subgroup. Based on a number of grouping heuristics, the DSG protocol attempts to find the partitioning of the receivers that maximizes the inter-receiver fairness of the session. The DSG protocol can result in a session receiving a higher bandwidth allocation when it is split into multiple connections. We address this issue by proposing a mechanism in which the connections split from a single multicast session are treated as a single aggregated-allocation connection (AAC). A Set of examples demonstrate the effectiveness of the DSG scheme incorporating the AAC technique on improving inter-receiver fairness for multicast ABR sessions.

  • Scalable and adaptive video multicast over the internet
    1998
    Co-Authors: Xue Li, M.h. Ammar
    Abstract:

    Multicast distribution of video is an important service for many existing and future Internet applications. Today's Internet lacks support for quality of service (QoS) provision, which makes the transmission of real-time video challenging. In addition, the heterogeneity of the Internet's transmission capacities and end-systems makes it extremely difficult to agree on acceptable traffic characterization among multiple receivers of the same video stream. The thesis presents our work in scalable and adaptive video multicast to meet the above challenges. The objective of our work is to explore the feasibility and techniques for video multicast over large scale heterogeneous networks with end to end control. Such techniques can be applied both in best-effort networks, such as the Internet, and in networks with QoS provision to accommodate variations and inaccuracies in resource reservation. To address the fairness problem of video multicast in a heterogeneous environment, we explore both layered video multicast and replicated stream video multicast. In layered video multicast, the video source compresses video into several layers and multicasts each layer to a separate multicast group. The receivers dynamically adapt to the appropriate video layers according to their processing power and network conditions. We develop a novel scheme to support Hierarchical Rate Control (HRC), which is incorporated into our Layered Video Multicast with Retransmissions (LVMR) protocol. In replicated stream video multicast, we explore the Destination Set Grouping (DSG) approach in which a video source transmits a small number of video streams carrying the same video at different quality levels. Each receiver chooses the appropriate stream to receive. This scheme is shown to improve fairness significantly at a small bandwidth cost. Our work also proposes solutions to improve the bandwidth efficiency of the DSG protocol. To further improve the video transmission quality over best-effort networks, we develop retransmission-based error control mechanisms, utilizing smart retransmission and local recovery. A novel scheme, adaptive playback, is propose to dynamically adapt playback point of video frames in time of congestion to allow more successful retransmission for lost packets. To achieve fair resource sharing among competing sessions, we proposed multi-session video rate control schemes to enhance current layered video multicast rate control protocols, such that improvement in fair resource sharing can be achieved both among multiple video multicast sessions, and between video sessions and TCP sessions.

  • HPDC - Bandwidth control for replicated-stream multicast video distribution
    Proceedings of 5th IEEE International Symposium on High Performance Distributed Computing HPDC-96, 1996
    Co-Authors: Xue Li, M.h. Ammar
    Abstract:

    Real-time multicast video distribution is an important component of many multimedia applications. Our work addresses the fairness problem in feedback-controlled multicast video distribution systems over best effort networks (such as the Internet). We have proposed, implemented and experimented with a scheme called Destination Set grouping (DSG), where a source maintains a small number of video streams, all carrying the same video but each targeted at receivers with different capabilities. Each stream is feedback-controlled within prescribed limits by its group of receivers. Receivers may move among groups as their capabilities or the capabilities of the network paths leading to them change. In this paper, we focus on the potential for network overloading caused by the transmission of multiple replicated streams. We propose a number of mechanisms to be implemented at the source and the receivers that can help avert this problem. We also describe an evaluation of these schemes using simulation, and discuss a comparison of replicated-stream versus layered-encoding approaches.

  • using Destination Set grouping to improve the performance of window controlled multipoint connections
    Computer Communications, 1996
    Co-Authors: Shun Yan Cheung, M.h. Ammar
    Abstract:

    In conventional multicast communication, the source carries a single conversation with all Destination nodes. If a node on the path to any Destination becomes congested, the throughput to all Destinations is reduced, thus treating some Destination nodes unfairly. We consider a window-controlled multipoint connection and study the use of Destination Set grouping, where the Destination Set can be split into disjoint subgroups with the source carrying independent conversations with each subgroup. We present a static grouping heuristic that can obtain near optimum grouping for static network environments and a dynamic grouping protocol which can adjust the grouping and the window sizes per group in response to changing network conditions. The performance of the static grouping heuristic and the dynamic grouping protocol are studied using simulation and compared with single-group multicasting.

  • INFOCOM - On the use of Destination Set grouping to improve fairness in multicast video distribution
    Proceedings of IEEE INFOCOM '96. Conference on Computer Communications, 1996
    Co-Authors: Shun Yan Cheung, M.h. Ammar, Xue Li
    Abstract:

    In a fair multicast video distribution scheme each receiver should receive a video stream with a quality that is commensurate with its capabilities or the capabilities of the path leading to it, regardless of other receivers or network paths. This fairness problem results from the fact that multicast communication trades economy of bandwidth with granularity of control. Distributing video using individual feedback-controlled point-to-point streams results in high bandwidth utilization but the granularity of control is high as communication parameters can be negotiated individually with each receiver. In contrast, using a single multicast stream has good bandwidth economy, but very low granularity of control. In this paper we propose, implement and experiment with a system that spans the spectrum represented by the two extremes above. In the scheme, called Destination Set grouping (DSG), a source maintains a small number of video streams, carrying the same video but each targeted at receivers with different capabilities. Each stream is feedback-controlled within prescribed limits by its group of receivers. Receivers may move among streams as their capabilities or the capabilities of the network paths leading to them change. The scheme is shown to improve fairness significantly at a small bandwidth cost.

D.a. Wood - One of the best experts on this subject based on the ideXlab platform.

  • Using Destination-Set prediction to improve the latency/bandwidth tradeoff in shared-memory multiprocessors
    30th Annual International Symposium on Computer Architecture 2003. Proceedings., 2003
    Co-Authors: M.m.k. Martin, P.j. Harper, D.j. Sorin, M.d. Hill, D.a. Wood
    Abstract:

    Destination Set prediction can improve the latency/bandwidth tradeoff in shared memory multiprocessors. The Destination Set is the collection of processors that receive a particular coherence request. Snooping protocols send requests to the maximal Destination Set (i.e., all processors), reducing latency for cache to cache misses at the expense of increased traffic. Directory protocols send requests to the minimal Destination Set, reducing bandwidth at the expense of an indirection through the directory for cache to cache misses. Recently proposed hybrid protocols tradeoff latency and bandwidth by directly sending requests to a predicted Destination Set. We explore the Destination Set predictor design space, focusing on a collection of important commercial workloads. First, we analyze the sharing behavior of these workloads. Second, we propose predictors that exploit the observed sharing behavior to target different points in the latency/bandwidth tradeoff. Third, we illustrate the effectiveness of Destination Set predictors in the context of a multicast snooping protocol. For example, one of our predictors obtains almost 90% of the performance of snooping while using only 15% more bandwidth than a directory protocol (and less than half the bandwidth of snooping).

  • using Destination Set prediction to improve the latency bandwidth tradeoff in shared memory multiprocessors
    International Symposium on Computer Architecture, 2003
    Co-Authors: M.m.k. Martin, P.j. Harper, D.j. Sorin, M.d. Hill, D.a. Wood
    Abstract:

    Destination-Set prediction can improve the latency/bandwidth tradeoff in shared-memory multiprocessors. The Destination Set is the collection of processors that receive a particular coherence request. Snooping protocols send requests to the maximal Destination Set (i.e., all processors), reducing latency for cache-to-cache misses at the expense of increased traffic. Directory protocols send requests to the minimal Destination Set, reducing bandwidth at the expense of an indirection through the directory for cache-to-cache misses. Recently proposed hybrid protocols trade-off latency and bandwidth by directly sending requests to a predicted Destination Set.This paper explores the Destination-Set predictor design space, focusing on a collection of important commercial workloads. First, we analyze the sharing behavior of these workloads. Second, we propose predictors that exploit the observed sharing behavior to target different points in the latency/bandwidth tradeoff. Third, we illustrate the effectiveness of Destination-Set predictors in the context of a multicast snooping protocol. For example, one of our predictors obtains almost 90% of the performance of snooping while using only 15% more bandwidth than a directory protocol (and less than half the bandwidth of snooping).

  • ISCA - Using Destination-Set prediction to improve the latency/bandwidth tradeoff in shared-memory multiprocessors
    Proceedings of the 30th annual international symposium on Computer architecture - ISCA '03, 2003
    Co-Authors: M.m.k. Martin, P.j. Harper, D.j. Sorin, M.d. Hill, D.a. Wood
    Abstract:

    Destination-Set prediction can improve the latency/bandwidth tradeoff in shared-memory multiprocessors. The Destination Set is the collection of processors that receive a particular coherence request. Snooping protocols send requests to the maximal Destination Set (i.e., all processors), reducing latency for cache-to-cache misses at the expense of increased traffic. Directory protocols send requests to the minimal Destination Set, reducing bandwidth at the expense of an indirection through the directory for cache-to-cache misses. Recently proposed hybrid protocols trade-off latency and bandwidth by directly sending requests to a predicted Destination Set.This paper explores the Destination-Set predictor design space, focusing on a collection of important commercial workloads. First, we analyze the sharing behavior of these workloads. Second, we propose predictors that exploit the observed sharing behavior to target different points in the latency/bandwidth tradeoff. Third, we illustrate the effectiveness of Destination-Set predictors in the context of a multicast snooping protocol. For example, one of our predictors obtains almost 90% of the performance of snooping while using only 15% more bandwidth than a directory protocol (and less than half the bandwidth of snooping).