Scalable Multicast Provisioning in DiffServ with MPLS Labeling

The phenomenal growth of multimedia applications imposes scalable and efficient network support. The DiffServ and MPLS architectures were developed to provide QoS. The combination of both architectures presents a very attractive strategy to backbone network providers. However, integrating native IP multicasting with MPLS supports DiffServ is a quite comple issue. Major problems are: the lack of labels in MPLS networks, the core routers simplicity in DiffServ and the multicast state scalability problems, since it requires routers to keep a forwarding state for every multicast tree passing through it. In addition, the number of states grows with the number of groups. Under such circumstance, we propose an hybrid label aggregation algorithm in order to solve multicast scalability problem and provide a solution for multicast in MPLS support DiffServ. In the proposed scheme, one label is assigned per multicast groups (logical aggregation) and different multicast groups sharing the same output interface in a router are aggregated locally (physical aggregation). Also, in order to support the proposed algorithm, we propose a separate treatment and labels space (prime numbers range) for multicast traffic. The proposed solution allows consuming fewer labels, reducing the forwarding table and consequently the total packet processing delay.     

基于双向共享树的MPLS多播流聚合算法

可扩展性是影响多播在MPLS网络大规模使用的主要问题,为解决该问题提出了一种基于双向共享树的多播流聚合算法.它根据节点之间的关系计算多播流的可聚合度,然后将标记边缘路由器聚类生成共享树的叶子节点集,并由树管理服务器计算双向共享树的拓扑结构,最后将可聚合度大于指定阈值的多播流汇聚到树中.实验结果表明,该算法可以大幅缩小MPLS标记的占用,简化中间节点的处理过程,减少路由器的转发状态,大大提高了MPLS多播的可扩展性.     

A Distributed Routing Method for Dynamic Multicasting

Single point, sender based control does not scale well for multicast delivery. For applications, such as group video or teleconferencing a low total cost multicast tree is required. In this article we present a destination driven algorithm to minimize the total tree cost of multicast tree in a dynamic situation for the whole session duration. In this heuristic approach we considered the staying duration of participants are available at the time of joining. The performance of our algorithm is analyzed through extensive simulation and evaluated against several other existing dynamic multicast routing and also against one well known near optimum heuristic algorithm used for solving Steiner tree problem. We have further tested our algorithm using erroneous information given by the joining participants. Simulation results show that its performance does not degrade that much even when the range of error is considerably high, which proves the robustness of our algorithm.     

Minimum coding nodes multicast tree for two-channel all-optical network coding scheme

A heuristic algorithm of establishing a minimum coding nodes multicast tree on which a two-channel all-optical network coding scheme can be performed is presented.To minimize the coding nodes,the heuri...     

共享路径优先组播路由算法

求解开销最小组播树在数学上归结为Steiner树问题,但由于寻找最优的Steiner树问题是NP-Complete问题,因此在组播应用中,采用启发式算法获得次优的组播树是常见的方法。该文提出了一种新的的启发式组播路由算法(Shared Path First Heuristic,SPFH)该算法在选择目的节点加入组播树时,既考虑到目的节点到树上的距离,又考虑到先加入的节点对后续加入节点的影响。算法从距离当前组播树近的目的节点中挑选节点加入组播树,选择的规则是,把能够减小其它目的节点加入组播树开销的节点先加入树。仿真结果表明,SPFH算法能找到开销接近于最优解的组播树。     

Improved heuristics for multicast routing in wireless mesh networks

Multicast is a communication technique that allows a source to transmit data to a set of recipients in an efficient manner. Therefore, the primary objective of a multicast routing protocol would be to minimize number of transmissions to conserve bandwidth. The problem of computing multicast trees with minimal bandwidth consumption is similar to Steiner tree problem and has shown to be NP-complete. So, heuristic based algorithms are suitable to approximate such bandwidth optimal trees. This paper proposes a multicast routing protocol based on minimum number of transmission trees using an heuristic approach. The simulation results show that the proposed algorithm offers better performance over existing protocols, even in the worst-case scenario when the set of multicast receivers are sparsely distributed across the network.     

Multi-Constrained Dynamic QoS Multicast Routing Design Using Ant Colony System

1IntroductionThe objective of Dynamic QoS Multicast Routing(DQMR) is to find the opti mal routing trees in the fu-ture real-ti me communication network, where informa-tion or messages are sent fromthe source nodeto all des-tination nodes , while meeting all QoS requirements forevery admitted connection and achieving global efficien-cy in resource utilization. Different applications haverather diverse QoS constraints on bandwidth, delay,delayjitter and so on. Multiple constraints often mak…     

A new heuristic algorithm for finding minimum‐cost multicast trees with bounded path delay

This article presents a new heuristic algorithm called DDBMA (Dynamic Delay Bounded Multicast Algorithm) to construct a minimum‐cost multicast tree. The heuristic depends on (1) bounded delay along paths from source nodes to each destination node; (2) minimum cost of the multicast tree; (3) dynamic multicast tree status which is maintained by updating the existing multicast tree when nodes in the network request to join or leave. Copyright © 1999 John Wiley & Sons, Ltd.     

一种多约束QoS多播路由算法

提出了带宽时延约束、代价最小的QoS多播路由模型,并提出了一种启发式算法求解该问题,分析了算法的复杂度。仿真试验证明,该算法是稳定有效的。它能够在满足两种约束的情况下,使多播树的代价优化。     

基于克隆选择的QoS组播路由优化

衡量QoS组播路由主要性能指标有延时,代价,带宽等,本文所提出的基于遗传算法的多约束QoS组播路由优化算法.引入了一个综合性能指标Q适应度函数,对延时、带宽、代价这3个性能指标进行权衡.以减小组播树的代价和延时,增大带宽,提高组播的服务质量.并对解决传统算法对于存在两组及以上的组播树,他们的代价都是最优的,延时和带宽都满足受限条件时无法选择的问题十分有效的.     

Distributed algorithms for multicast path setup in data networks

Establishing a multicast tree in a point-to-point network of switch nodes, such as a wide-area asynchronous transfer mode (ATM) network, can be modeled as the NP-complete Steiner problem in networks. In this paper, we introduce and evaluate two distributed algorithms for finding multicast trees in point-to-point data networks. These algorithms are based on the centralized Steiner heuristics, the shortest path heuristic (SPH) and the Kruskal-based shortest path heuristic (K-SPH), and have the advantage that only the multicast members and nodes in the neighborhood of the multicast tree need to participate in the execution of the algorithm. We compare our algorithms by simulation against a baseline algorithm, the pruned minimum spanning-tree heuristic that is the basis of many previously published algorithms for finding multicast trees. Our results show that the competitiveness (the ratio of the sum of the heuristic tree's edge weights to that of the best solution found) of both of our algorithms was, on the average, 25% better in comparison to that of the pruned spanning-tree approach. In addition, the competitiveness of our algorithms was, in almost all cases, within 10% of the best solution found by any of the Steiner heuristics considered, including both centralized and distributed algorithms. Limiting the execution of the algorithm to a subset of the nodes in the network results in an increase in convergence time over the pruned spanning-tree approach, but this overhead can be reduced by careful implementation     

A dynamic multicast routing satisfying multiple QoS constraints

In this paper we propose a QoS‐based routing algorithm for dynamic multicasting. The complexity of the problem can be reduced to a simple shortest path problem by applying a Weighted Fair Queuing (WFQ) service discipline. Using a modified Bellman–Ford algorithm, the proposed routing builds a multicast tree, where a node is added to the existing multicast tree without re‐routing and satisfying QoS constraints. With user defined life‐time of connection this heuristic algorthm builds multicast tree which is near optimum over the whole duration of session. Simulation results show that tree costs are nearly as good as other dynamic multicast routings that does not consider QoS. Copyright © 2003 John Wiley & Sons, Ltd.     

支持延时约束的覆盖多播路由协议的研究

研究有度和延时约束的覆盖多播路由问题,提出了一个新的覆盖多播路由协议-延时受限的树协议(DBTP)。该协议采用分布式和树优先的策略,使多播组成员之间能自组织地构建一棵基于源的覆盖多播树。DBTP协议采用了一种新的启发式局部优化算法,通过调节启发因子,能灵活地在延时和代价之间进行折衷。仿真实验表明,无论在静态还是动态节点模型下,选择适当的启发参数,DBTP都能获得较高的节点接纳率。     

Exploring Performance of Hypercube Structure for Multicast in Mobile Ad Hoc Networks

Performance of multicast routing protocol in mobile ad hoc networks is mostly characterized by underlying forwarding structure. Currently, general structures based on tree/mesh based scheme cannot handle with transmission efficiency, robustness to dynamic topology, scalability, and load balancing functionalities at the same time. To handle above key performance factors concurrently, we propose a new virtual backbone architecture for multicast, which is based on hierarchical hypercube structure. Due to the natural properties of hypercube structure, we can achieve efficiency, robustness and load balance in mobile ad hoc networks where links are frequently broken owing to nodes’ free immigration. Furthermore, scalability problem is naturally resolved by hierarchical structure. Finally, through simulation results, we have proven good scalability by demonstrating that our structure can provide higher packet delivery ratio with low control overhead and better scalability than tree/mesh based scheme without regard to the number of group members.     

A new delay‐constrained algorithm for multicast routing tree construction

New multimedia applications provide guaranteed end‐to‐end quality of service (QoS) and have stringent constraints on delay, delay‐jitter, bandwidth, cost, etc. The main task of QoS routing is to find a route in the network, with sufficient resources to satisfy the constraints. Most multicast routing algorithms are not fast enough for large‐scale networks and where the source node uses global cost information to construct a multicast tree. We propose a fast and simple heuristic algorithm (EPDT) for delay‐constrained routing problem for multicast tree construction. This algorithm uses a greedy strategy based on shortest‐path and minimal spanning trees. It combines the minimum cost and the minimum radius objectives by combining respectively optimal Prim's and Dijkstra's algorithms. It biases routes through destinations. Besides, it uses cost information only from neighbouring nodes as it proceeds, which makes it more practical, from an implementation point of view. Copyright © 2004 John Wiley & Sons, Ltd.     

Video distribution on multicast networks

The Internet is being used to distribute video programming to small, widely distributed audiences over a multicast backbone (Mbone). This type of service can be used to deliver specialized programming to the general population. As the service becomes more widely used, conserving the required transmission facilities becomes more important. We define the problem of designing multicast networks for video distribution. The problem is related to the Steiner tree problem, with an interesting twist. The line costs are not constant. An heuristic is developed to solve the problem and the new heuristic is related to and compared with heuristics, developed for the Steiner tree problem and algorithms to design minimum depth and minimum spanning trees     

MR-MC无线传感器网络最小延迟数据聚集调度研究

单radio单信道无线传感器网络的最小延迟聚集调度是一个NPC问题,已提出许多解决方案。在多radio多信道网络中,节点可以同时接收多个不同节点传输的数据,降低延迟。基于上述特点,考虑树结构约束,时槽、信道和radio分配等约束条件,将多radio多信道无线传感器网络最小延迟聚集调度问题定义为一个优化问题,并分解为建立聚集树和节点调度2个子问题,针对这2个子问题分别提出启发式算法。实验结果表明,提出的算法具有良好的性能。     

ARIES: a rearrangeable inexpensive edge-based on-line Steineralgorithm

Many future applications of computer networks such as distance education, remote collaboration, and teleconferencing will rely on the ability of the network to provide multicast services. We propose and evaluate ARIES, a heuristic for updating multicast trees dynamically in large point-to-point networks. The algorithm is based on monitoring the accumulated damage to the multicast tree within local regions or the tree as nodes are added and deleted and triggering a rearrangement when the number of changes within a connected subtree crosses a set threshold. We derive an analytical upper bound on the competitiveness of the algorithm. We also present simulation results to compare the average-case performance of the algorithm with two other known algorithms for the dynamic multicast problem, GREEDY, and edge-bounded algorithm (EBA). Our results show that ARIES provides the best balance among competitiveness, computational effort, and changes in the multicast tree after each update     

A rearrangeable algorithm for the construction of delay-constraineddynamic multicast trees

With the proliferation of multimedia group applications, the construction of multicast trees satisfying quality of service (QoS) requirements is becoming a problem of prime importance. Many of the multicast applications (such as video broadcasts and teleconferencing) require the network to support dynamic multicast sessions wherein the membership of the multicast group changes with time. In this paper, we propose and evaluate an algorithm called CRCDM (controlled rearrangement for constrained dynamic multicasting) for on-line update of multicast trees to adjust to changes in group membership. The CRCDM algorithm is based on a concept called quality factor (QF) that represents the usefulness of a portion of the multicast tree to the overall multicast session. When the usefulness of a particular region of the tree drops below a threshold, a rearrangement technique is used to suitably modify the tree. Our algorithm aims to satisfy the delay constraints of all current group members, at the same time minimizing the cost of the constructed tree. We compare the performance of our algorithm, by simulation, with that of an off-line Steiner heuristic; with ARIES, a previously published algorithm for on-line update of unconstrained trees; and with the algorithm proposed by Hong, Lee and Park (see Proc. IEEE INFOCOM, p.1433-40, 1998) for on-line update of delay-constrained trees. The simulation results indicate that our algorithm provides excellent cost-competitiveness that is better than that provided by the algorithm described by Hong et al., minimizes changes in the multicast tree after each update, and performs favorably even when compared with the unconstrained ARIES heuristic     

Minimizing the Number of Multicast Transmissions in Single-Hop WDM Networks

The problem of minimizing the number of transmissions for a multicast transmission under the condition that the packet delay is minimum in single-hop wavelength division multiplexing (WDM) networks is studied in this paper. This problem is proved to be NP-complete. A heuristic multicast scheduling algorithm is proposed for this problem. Extensive simulations are performed to compare the performance of the proposed heuristic algorithm with two other multicast scheduling algorithms, namely, the greedy and no-partition scheduling algorithms. The greedy algorithm schedules as many destination nodes as possible in the earliest data slot. The no-partition algorithm schedules the destination nodes of a multicast packet to receive the packet in the same data slot without partitioning the multicast transmission into multiple unicast or multicast transmissions. Our simulation results show that (i) an algorithm which partitions a multicast transmission into multiple unicast or multicast transmissions may not always produce lower mean packet delay than the no-partition algorithm when the number of data channels in the system is limited and (ii) the proposed heuristic algorithm always produces lower mean packet delay than the greedy and the no-partition algorithms because this algorithm not only partitions a multicast transmission into multiple unicast or multicast transmissions to keep the packet delay low but also reduces the number of transmissions to conserve resources.