Cost Of Multicast Tree Research Articles

A FAST HYBRID ALGORITHM FOR MULTICAST ROUTING IN WIRELESS NETWORKS

This paper tackles the issue of constrained multicast routing in wireless networks using a hybrid soft computing-based algorithm. Recent developments in multimedia applications and the dynamic and rapidly changed environment of the wireless networks make the constrained multicast routing a real challenge. The problem can be formulated as minimizing a multicast tree cost under several constraints or Quality of Service (QoS) metrics. This problem has been proven to be NP-complete. The proposed hybrid algorithm is based on a population based incremental learning algorithm that combines in an efficient way the features of genetic algorithms and competitive learning. Experimental results show that, in most cases, the proposed algorithm yields better solutions than other heuristic algorithms proposed in the literature.

Cost of multicast logical key tree based on hierarchical data processing

How to design a multicast key management system with high performance is a hot issue now. This paper will apply the idea of hierarchical data processing to construct a common analytic model based on directed logical key tree and supply two important metrics to this problem: re-keying cost and key storage cost. The paper gives the basic theory to the hierarchical data processing and the analyzing model to multicast key management based on logical key tree. It has been proved that the 4-ray tree has the best performance in using these metrics. The key management problem is also investigated based on user probability model, and gives two evaluating parameters to re-keying and key storage cost.

An effective algorithm for delay-constrained dynamic multicasting

With the development of multimedia group applications, the construction of multicast routing tree satisfying Quality of Service (QoS) is more important. In many multicast applications, it is required that the network supports dynamic multicast, which the membership of the multicast group changes with the time. In this paper an effective heuristic algorithm is proposed for dynamic multicast routing with delay-constrained. Aims of this proposed algorithm is to guarantee that: (1) the cost of multicast tree is as small as possible at each node addition/removal event, (2) all the maximal path delay is meet a fixed delay-constrained, (3) minimize perturbation to an existing tree. The proposed algorithm is based on ‘damage’ and ‘usefulness’ concept, and a Balancing Factor (BF) is provided to judge whether or not to arrange a region of tree. Mutation operation in Genetic Algorithm (GA) is also employed to find an attached node in tree for a dynamic adding node. Simulation shows that our algorithm performs well than those static heuristic algorithms in term of cost especially.

An efficient algorithm for constructing delay bounded minimum cost multicast trees

Multimedia applications are usually resource intensive, have stringent quality of service requirements, and in many cases involve large groups of participants. Multicasting is poised to play an important role in future deployment of these applications. This paper focuses on developing delay-bounded, minimum-cost multicast trees, linking a source to a set of multicast destination nodes. The approach taken in this paper is efficient, flexible and unique in the sense that it cleverly limits its computation only to paths that originate at multicast nodes, thereby avoiding computing paths that exclusively link non-multicast nodes. The simulation results show that the multicast trees produced by the proposed heuristic are of lower cost than those produced by other well-known heuristics, including those which use an expensive k-shortest-paths procedure to minimize the cost of the multicast tree. Furthermore, the results show that, in comparison to other heuristics, the proposed scheme results in a significant reduction in the computation time required to build the multicast tree.

A Polynomial Time Approximation Scheme for Minimum Cost Delay-Constrained Multicast Tree under a Steiner Topology

This paper is concerned with a restricted version of minimum cost delay-constrained multicast in a network where each link has a delay and a cost. Given a source vertex $s$ and $p$ destination vertices $t_1, t_2, \ldots, t_p$ together with $p$ corresponding nonnegative delay constraints $d_1, d_2, \ldots, d_p$, many QoS multicast problems seek a minimum cost multicast tree in which the delay along the unique $s$--$t_i$ path is no more than $d_i$ for $1 \le i \le p$. This problem is NP-hard even when the topology of the multicast tree is fixed. In this paper we show that every multicast tree has an underlying Steiner topology and that every minimum cost delay-constrained multicast tree corresponds to a minimum cost delay-constrained realization of a corresponding Steiner topology. We present a fully polynomial time approximation scheme for computing a minimum cost delay-constrained multicast tree under a Steiner topology. We also present computational results of a preliminary implementation to illustrate the effectiveness of our algorithm and discuss its applications.

An improved multicast routing algorithm

Multicasting is a communication service that allows an application to efficiently transmit copies of data packets to a set of destination nodes. The problem of finding a minimum cost multicast tree can be formulated as a minimum Steiner tree problem in networks, which is NP-completeness. MPH (minimum path cost heuristic) algorithm is a famous solution to this problem. In this paper, we present a novel solution TPMPH (two phase minimum path cost heuristic) to improve the MPH by generating the nodes and the edges of multicast tree separately. The cost of multicast tree generated by the proposed algorithm with the same time as MPH is no more than that of MPH in the worst case. Extensive simulation results show that TPMPH can effectively improve the performance on MPH, and performs better in large-scale networks and wireless networks.

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.

Adaptive core selection and migration method for multicast routing in mobile ad hoc networks

Several multicast protocols such as Protocol Independent Multicast (PIM) (Deering et al., 1996) and Core-Based Trees (CBT) (Ballardie et al., 1993) use the notion of group-shared trees. The reason is that construction of minimal-cost tree spanning all members of the multicast group is expensive, hence these protocols use a core-based group-shared tree to distribute packets from all the sources. A core-based tree is a shortest-path tree rooted at some core node. The core node is also referred to as a center node or a rendezvous point. Core nodes may be chosen from some preselected set of nodes or some heuristics may be employed to select core nodes. We present distributed core selection and migration protocols for mobile ad hoc networks with dynamically changing network topology. Most protocols for core selection in static networks are not suitable for ad hoc networks, since these algorithms depend on knowledge of entire network topology, which is not available or is too expensive to maintain in an ad hoc network with dynamic topology. The proposed core location method is based on the notion of median node of the current multicast tree instead of the median node of the entire network. The rationale is that the mobile ad hoc network graphs are in general sparse and, hence, the multicast tree is a good approximation of the entire network for the current purpose. Our adaptive distributed core selection and migration method uses the fact that the median of a tree is equivalent to the centroid of that tree. The significance of this observation is due to the fact that the computation of a tree's centroids does not require any distance information. Mobile ad hoc networks have limited bandwidth which needs to be conserved. Hence, we use the cost of multicast tree as the sum of weights of all the links in the tree, which signifies the total bandwidth consumed for multicasting a packet. We compare the cost of shortest-path tree rooted at the tree median, Cost/sub TM/, with the cost of shortest-path tree rooted at the median of the graph, Cost/sub GM/, which requires complete topology information to compute. A network graph model for generating random ad hoc mobile networks is developed to perform this comparison. The simulation results show that for large size networks, the ratio Cost/sub TM//Cost/sub GM/ lies between 0.8 to 1.2 for different multicast groups. Further, as the size of the multicast group increases the ratio approaches 1.

A case for tree migration and integrated tree maintenance in QoS multicasting

The proliferation of QoS-aware group applications coupled with the limited availability of network resources demand for efficient mechanisms to support QoS multicasting. During a life-cycle of a multicast session, three important events can occur: membership dynamics, network dynamics, and traffic dynamics. The first two are concerned with maintaining a good quality (cost) multicast tree taking into account dynamic join/leave of members, and changes in network topology due to link/node failures/additions, respectively. The third aspect is concerned with flow, congestion, and error control. There has been many solutions proposed for dealing with each of these issues. However, the issue of tree migration has not been addressed as part of these solutions. In this paper, we highlight the importance of tree migration as a mechanism for handling membership and network dynamics in core-based multicasting, prove that it is NP-Complete, and propose four heuristic algorithms for it. The proposed algorithms are evaluated under two performance metrics: service disruption and resource wastage. Our simulation studies show that two of the algorithms offer comparable performance to that of the other two, in addition to being highly scalable and easily implementable. Moreover, we also propose an integrated approach for group management involving both local and global tree maintenance techniques.

Dynamic group multicast routing with bandwidth reservations

AbstractMulticasting refers to the transmission of data from a source node to multiple destination nodes in a network. Group multicasting is a generalization of multicasting whereby every member of a group is allowed to multicast messages to other members that belong to the same group. The routing problem in this case involves the construction of a set of low cost multicast trees with bandwidth requirements, one for each member of the group for multicasting messages to other members of the group. In this paper, we examine this routing problem with an additional requirement that member nodes are allowed to join and leave the multicasting group anytime during a session. We call this problem, the dynamic group multicast routing problem (DGMRP). In this paper, we proposed three heuristic algorithms to generate a set of low cost multicast trees with dynamic group membership. Results from our empirical study shows that the one of the proposed algorithms, called Maximum bandwidth bottleneck path selection algorithm (MBBPS), achieves better utilization of bandwidth resources as compared with the other two algorithms which are based on a greedy approach. In addition MBBPS performs better in terms of cost when the bandwidth is not sufficient in the network. Copyright © 2002 John Wiley & Sons, Ltd.

QoS-driven multicast tree generation using Tabu search

Many multimedia communication applications require a source to transmit messages to multiple destinations subject to Quality-of-Service (QoS) delay constraint. The problem to be solved is to find a minimum cost multicast tree where each source to destination path is constrained by a delay bound. This problem has been proven to be NP-complete. In this paper, we present a Tabu Search (TS) algorithm to construct a minimum cost delay bounded multicast tree. The proposed algorithm is then compared with many existing multicast algorithms. Results show that on almost all test cases, TS algorithm exhibits more intelligent search of the solution subspace and is able to find better solutions than other reported multicast algorithms.

An efficient algorithm for group multicast routing with bandwidth reservation

Multicasting refers to the transmission of data from a source node to multiple destination nodes in a network. Group multicasting is a generalisation of multicasting whereby every member of a group is allowed to multicast messages to other members that belong to the same group. The routing problem in this case involves the construction of a set of low cost multicast trees with bandwidth requirements, one for each member of the group, for multicasting messages to other members of the group. In this paper, we propose a new heuristic algorithm to generate a set of low cost multicast trees with bandwidth requirements. Simulation results show that our proposed algorithm performed better in terms of cost and in terms of utilisation of bandwidth as compared to an existing algorithm that was proposed by Jia and Wang [3].

Efficient multicast routing with delay constraints

To support real-time multimedia applications in BISDN networks, QoS guaranteed multicast routing is essential. Traditional multicast routing algorithms used for solving the Steiner tree problem cannot be used in this scenario, because QoS constraints on links are not considered. In this paper, we present two efficient source-based multicast routing algorithms in directed networks. The objective of the routing algorithms is to minimize the multicast tree cost while maintaining a bound on delay. Simulation results show that these two heuristics can greatly improve the multicast tree cost measure in comparison with the shortest path routing schemes. Their performance is close to that of the known CSTc algorithm proposed by Kompell et al. in Reference 1, but requiring a much shorter computation time. Copyright © 1999 John Wiley & Sons, Ltd.

Algorithms for delay-constrained low-cost multicast tree construction

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. Multicast groups are usually classified as sparse or pervasive groups depending on the physical distribution of group members. They are also classified based on the temporal characteristics of group membership into static and dynamic groups. In this paper, we propose two algorithms for constructing multicast trees for multimedia group communication in which the members are sparse and static. The proposed algorithms use a constrained distributed unicast routing algorithm for generating low-cost, bandwidth and delay constrained multicast trees. These algorithms have lower message complexity and call setup time due to their nature of iteratively adding paths, rather than edges, to partially constructed trees. We study the performance (in terms of call acceptance rate, call setup time and multicast tree cost) of these algorithms through simulation by comparing them with that of a recently proposed algorithm (V. Kompella, J.C. Pasquale, G.C. Polyzos, Two distributed algorithms for the constrained Steiner tree problem, in: Proc. Comp. Comm. Networking, San Diego, CA, June 1993) for the same problem. The simulation results indicate that the proposed algorithms provide larger call acceptance rates, lower setup times and comparable tree costs.

Distributed multicast routing for delay-sensitive applications

A distributed multicast algorithm for constructing minimum cost multicast trees with delay constraints is proposed. The proposed algorithm can always construct a delay-constrained multicast tree, if one exists, and exhibits superior tree cost performance compared to existing algorithms.