Dynamic multicast traffic grooming in wave-length division multiplexing(WDM)networks was analyzed to minimize networkwide costs and to increase the network resource utilization.A network model was developed for dynami...Dynamic multicast traffic grooming in wave-length division multiplexing(WDM)networks was analyzed to minimize networkwide costs and to increase the network resource utilization.A network model was developed for dynamic multicast traffic grooming with resource constraints and an algorithm that can provide quality of service(QoS)was proposed.The QoS is measured by the maximum number of lightpaths passing between the source and the destinations.The blocking probability of the algorithm was assessed in simulations.The results show that a higher QoS requirement results in higher blocking probability,and when the QoS requirement is low,changes in the QoS require-ments have only small effects on the blocking probability.展开更多
The goal of quality-of-service （QoS） multicast routing is to establish a multicast tree which satisfies certain constraints on bandwidth, delay and other metrics. The network state information maintained at every no...The goal of quality-of-service （QoS） multicast routing is to establish a multicast tree which satisfies certain constraints on bandwidth, delay and other metrics. The network state information maintained at every node is often im- precise in a dynamic environment because of non-negligible propagation delay of state messages, periodic updates due to overhead concern, and hierarchical state aggregation. The existing QoS multicast routing algorithms do not provide satisfactory performance with imprecise state information. We propose a distributed QoS multicast routing scheme based on traffic lights, called QMRI algorithm, which can probe multiple feasible tree branches, and select the optimal or near-optimal branch through the UR or TL mode for constructing a multicast tree with QoS guarantees if it exists. The scheme is designed to work with imprecise state information. The proposed algorithm considers not only the QoS requirements but also the cost optimality of the multicast tree. The correctness proof and the complexity analysis about the QMRI algorithm are also given. In addition, we develop NS2 so that it is able to simulate the imprecise network state information. Extensive simulations show that our algorithm achieves high call-admission ratio and low-cost multicast trees with modest message overhead.展开更多
Group multicast routing algorithms satisfying quality of service requirements of real-time applications are essential for high-speed networks. A heuristic algorithm was presented for group multicast routing with bandw...Group multicast routing algorithms satisfying quality of service requirements of real-time applications are essential for high-speed networks. A heuristic algorithm was presented for group multicast routing with bandwidth and delay constrained. A new metric was designed as a function of available bandwidth and delay of link. And source-specific routing trees for each member were generated in the algorithm by using the metric, which satisfy member′s bandwidth and end-to-end delay requirements. Simulations over random network were carried out to compare the performance of the proposed algorithm with that from literature.Experimental results show that the algorithm performs better in terms of network cost and ability in constructing feasible multicast trees for group members. Moreover,the algorithm can avoid link blocking and enhance the network behavior efficiently.展开更多
To provide scalable and simple Quality of Service(QoS) mechanism for multicast services, Probe-Based Multicast Admission Control (PBMAC) scheme was proposed. In this paper, PBMAC is studied and a so-called subsequent ...To provide scalable and simple Quality of Service(QoS) mechanism for multicast services, Probe-Based Multicast Admission Control (PBMAC) scheme was proposed. In this paper, PBMAC is studied and a so-called subsequent request problem is found in PBMAC, which degrades system performance significantly when the network traffic is heavily loaded. Based on the analysis on subsequent request problem, an Enhance PBMAC (EPBMAC) scheme is proposed, in which complementary probing is devised to solve the problem. Using a new metric of normalized requested equivalent link capacity, the performance of PBMAC and EPBMAC is analyzed and evaluated. Two implementations are proposed for incremental deployment. The paper finally introduces evaluation with packet-based simulations. Both analytical and simulation results show the significant improvement in performance.展开更多
文摘Dynamic multicast traffic grooming in wave-length division multiplexing(WDM)networks was analyzed to minimize networkwide costs and to increase the network resource utilization.A network model was developed for dynamic multicast traffic grooming with resource constraints and an algorithm that can provide quality of service(QoS)was proposed.The QoS is measured by the maximum number of lightpaths passing between the source and the destinations.The blocking probability of the algorithm was assessed in simulations.The results show that a higher QoS requirement results in higher blocking probability,and when the QoS requirement is low,changes in the QoS require-ments have only small effects on the blocking probability.
文摘The goal of quality-of-service （QoS） multicast routing is to establish a multicast tree which satisfies certain constraints on bandwidth, delay and other metrics. The network state information maintained at every node is often im- precise in a dynamic environment because of non-negligible propagation delay of state messages, periodic updates due to overhead concern, and hierarchical state aggregation. The existing QoS multicast routing algorithms do not provide satisfactory performance with imprecise state information. We propose a distributed QoS multicast routing scheme based on traffic lights, called QMRI algorithm, which can probe multiple feasible tree branches, and select the optimal or near-optimal branch through the UR or TL mode for constructing a multicast tree with QoS guarantees if it exists. The scheme is designed to work with imprecise state information. The proposed algorithm considers not only the QoS requirements but also the cost optimality of the multicast tree. The correctness proof and the complexity analysis about the QMRI algorithm are also given. In addition, we develop NS2 so that it is able to simulate the imprecise network state information. Extensive simulations show that our algorithm achieves high call-admission ratio and low-cost multicast trees with modest message overhead.
基金Supported by China Postdoctoral Science Foundation (No.20030056007).
文摘Group multicast routing algorithms satisfying quality of service requirements of real-time applications are essential for high-speed networks. A heuristic algorithm was presented for group multicast routing with bandwidth and delay constrained. A new metric was designed as a function of available bandwidth and delay of link. And source-specific routing trees for each member were generated in the algorithm by using the metric, which satisfy member′s bandwidth and end-to-end delay requirements. Simulations over random network were carried out to compare the performance of the proposed algorithm with that from literature.Experimental results show that the algorithm performs better in terms of network cost and ability in constructing feasible multicast trees for group members. Moreover,the algorithm can avoid link blocking and enhance the network behavior efficiently.
文摘To provide scalable and simple Quality of Service(QoS) mechanism for multicast services, Probe-Based Multicast Admission Control (PBMAC) scheme was proposed. In this paper, PBMAC is studied and a so-called subsequent request problem is found in PBMAC, which degrades system performance significantly when the network traffic is heavily loaded. Based on the analysis on subsequent request problem, an Enhance PBMAC (EPBMAC) scheme is proposed, in which complementary probing is devised to solve the problem. Using a new metric of normalized requested equivalent link capacity, the performance of PBMAC and EPBMAC is analyzed and evaluated. Two implementations are proposed for incremental deployment. The paper finally introduces evaluation with packet-based simulations. Both analytical and simulation results show the significant improvement in performance.
