QoS Multicast Routing Research Articles

QoS multicast routing for multimedia group communications using intelligent computational methods

In this paper, we investigate the problem of quality-of-service (QoS) multicast routing for multimedia group communications. We first develop a unified framework for achieving QoS multicast trees using intelligent computational methods. The framework consists of the model for multimedia communication network, the formulation of QoS multicast routing problem, and three key components used in intelligent computational methods-based QoS multicast routing algorithms. Then we propose three QoS multicast algorithms based on three representative intelligent computational methods (i.e., genetic algorithm, simulated annealing, and Tabu search), separately. In these algorithms, both the network resource requirements and the end-to-end delay are considered as the QoS parameters. Various issues are analyzed and designed for applying these three intelligent computational methods to construct QoS multicast trees. By simulation, we evaluate the performance of these three algorithms on a small-scale real-world multimedia communication network and a randomly generated large-scale network. Simulation results show that our algorithms can find near-optimal QoS multicast trees with high success rate. We also compare the running time among them, which help explain the algorithmic structures.

A QoS multicast routing optimization algorithm based on genetic algorithm

Most of the multimedia applications require strict quality of service (QoS) guarantee during the communication between a single source and multiple destinations. This gives rise to the need for an efficient QoS multicast routing strategy. Determination of such QoS-based optimal multicast routes basically leads to a multi-objective optimization problem, which is computationally intractable in polynomial time due to the uncertainty of resources in Internet. This paper describes a network model for researching the routing problem and proposes a new multicast tree selection algorithm based on genetic algorithms to simultaneously optimize multiple QoS parameters. The paper mainly presents a QoS multicast routing algorithm based on genetic algorithm (QMRGA). The QMRGA can also optimize the network resources such as bandwidth and delay, and can converge to the optimal or near-optimal solution within few iterations, even for the networks environment with uncertain parameters. The incremental rate of computational cost can close to polynomial and is less than exponential rate. The performance measures of the QMRGA are evaluated using simulations. The simulation results show that this approach has fast convergence speed and high reliability. It can meet the real-time requirement in multimedia communication networks.

QoS-based multicast routing optimization algorithms for Internet

Most of the multimedia applications require strict Quality-of-Service (QoS) guarantee during the communication between a single source and multiple destinations. The paper mainly presents a QoS Multicast Routing algorithms based on Genetic Algorithm (QMRGA). Simulation results demonstrate that the algorithm is capable of discovering a set of QoS-based near optimized, non-dominated multicast routes within a few iterations, even for the networks environment with uncertain parameters.

Mobile multimedia supports with hierarchical multicast SIP framework on heterogeneous wireless networks

For supporting the mobile host (MH) to be the multicast receivers on wireless networks, the traditional approaches such as the Hierarchical Remote Subscription (HRS) and Bi-directional Tunneling with Mobile Multicast (BT-MoM) integrate the Mobile IP protocol with the IP multicast technique. However, they inherit intrinsic problems to handle mobility and suffer significant delays to rebuild the multicast tree when the MH moves out of the multicast tree, which results in serious playback interruption and quality of service (QoS) degradation for the ongoing multimedia service especially when the MH are scattered over different kinds of wireless networks. In this paper, we propose a cross-layer framework and the Hierarchical Multicast Session Initiation Protocol (HMSIP), which extend the IETF Session Initiation Protocol (SIP) with the concept of multicast SIP session and integrate the underlying IP Multicast QoS routing protocol and the RSVP resource reservation technique, to support mobile multimedia multicasts. This framework significantly reduces handoff delays and deployment costs and hence achieves end-to-end QoS support for MHs on heterogeneous wireless networks. Further, we mathematically analyze handoff delays of the HRS, BT-MOM and HMSIP schemes. Moreover, simulation results show that the HMSIP can significantly achieve much more stable and lower handoff delays than those of the BT-MOM and HRS only with a small proportion of extra bandwidth than the bandwidth-optimal HRS, thereby supporting higher numbers of handoffs without interrupting multimedia playback of the mobile multicast activity. Tradeoffs between costs for deploying HMSIP Proxies in the framework and corresponding performances of the HMSIP families are discussed. Finally, multimedia QoS improvements of MHs are shown to emphasize advantages by integrating RSVP in this HMSIP framework.

A multi-constrained multicast QoS routing algorithm

Opposed to the situation that the constrained minimum Steiner tree (CMST) problem has been attracting much attention in quality of service (QoS) routing area, little work has been done on multicast routing subject to multiple additive constraints even though this is required by many emerging applications. In this paper, we propose a heuristic HMCMC to find feasible solutions to this problem. HMCMC has a provably low time complexity, and its basic idea is to construct a multicast tree step-by-step, which is done essentially based on the latest research results on multi-constrained unicast routing. Computer simulations demonstrate that HMCMC can achieve a high success ratio of finding feasible solutions.

Ad hoc qualiy of service multicast routing with objection queries for admission control

AbstractToday's handheld computing devices equipped with novel wireless network technologies can provide their users with features such as mobility, multimedia support and group communication. On the other hand, the administrative effort required to enable all these features increases beyond the level that an ordinary user can manage. Ad hoc networks, being able to quickly organise themselves without user intervention, can overcome this problem. They are also suitable for group‐oriented mobile multimedia communication. However, it is imperative for ad hoc networks to combine quality of service (QoS) and multicast routing strategies in order to utilise the wireless medium efficiently. This article defines the components of an ad hoc QoS multicast routing (AQM) protocol, which addresses this issue. AQM achieves multicast routing efficiency by tracking the availability of resources for each node within its neighbourhood. Computation of free bandwidth is based on reservations made for ongoing sessions and the allocations reported by neighbours. Current QoS status is announced at the initiation of a new session and updated periodically in the network to the extent of QoS provision. Thus, nodes are prevented from applying for membership if there is no QoS path for the session. When nodes wish to join a session with certain service requirements, a three‐phase process consisting of request, reply and reserve steps ensures that the QoS information is updated and used to select the most appropriate routes. The allowed maximum hop count of the session is taken into account in order to satisfy the delay requirements of the multimedia applications. To cope with the continuous nature of streaming multimedia, AQM nodes check the availability of bandwidth within their neighbourhood not only for themselves but within a virtual tunnel of nodes. Objection queries are issued prior to reservation to avoid excessive resource usage due to allocations made by nodes which cannot detect each other directly. New performance metrics are introduced to evaluate the efficiency of AQM regarding the satisfaction level of individual members as well as the success rate of sessions. Simulation results show that, by applying novel QoS management techniques, AQM significantly improves multicast efficiency for members as well as for sessions. Copyright © 2005 AEIT.

Ad hoc quality of service multicast routing

The conceptual shift in the expectations of the wireless users from voice towards multimedia, from availability towards acceptable quality, and from stand-alone towards group-oriented computing has a significant impact on today's networks in terms of the need for mobility, quality of service (QoS) and multicasting. Ad hoc networks, being independent of any fixed infrastructure, can provide mobile users with these features, if necessary QoS multicasting strategies are developed. The aim of this article is to define the building blocks of such an ad hoc QoS multicasting (AQM) protocol. AQM achieves multicasting efficiency by tracking the availability of resources for each node within its neighbourhood. Computation of free bandwidth is based on reservations made for ongoing sessions and similar information reported by neighbours. Current QoS status is announced at the initiation of a new session and updated periodically in the network to the extent of QoS provision. Thus, nodes are prevented from applying for membership if there is no QoS path for the session. When nodes join a session with certain service requirements, a request–reply–reserve process ensures that the QoS information is refreshed and used to select the most appropriate routes. To evaluate the efficiency of AQM in providing multicast users with QoS and satisfying application requirements, two new performance metrics, member and session satisfaction grades are introduced. AQM is compared to a non-QoS scheme with particular emphasis on these criteria. Simulation results show that, by applying QoS restrictions, AQM significantly improves multicasting efficiency. Thus, QoS is both essential for and applicable to multicasting in order to support mobile multimedia applications in ad hoc networks.

QoS multicast routing with delay constraints

Proliferation of group-based real-time applications, such as online games and video conferencing has motivated research into QoS multicast routing. These types of applications require consideration of both source-to-destination delay (i.e., packet delay from the source to all destinations) and inter-destination delay variation (i.e., the difference in packet delay from the source to different destinations) constraints. In this paper, we formulate a new combined problem for delay partitioning and multicast routing with source-to-destination delay and inter-destination delay variation constraints in a QoS framework, where a delay dependent cost function is associated with each network link. After identifying the problem asnp-complete, we introduce a Genetic Algorithm (ga) based algorithm that computes a source-based multicast tree which satisfies both constraints with near-optimal cost. We compare differentga schemes using different selection operators and find that the combination of Steady Statega and Remainder Stochastic Sampling selection operator works best for our problem. Simulation results also show that ourga heuristic consistently perfornis better than several other simple heuristics.

Resource Optimization in QoS Multicast Routing of Real-Time Multimedia

We consider a network design problem, where applications require various levels of Quality-of-Service (QoS) while connections have limited performance. Suppose that a source needs to send a message to a heterogeneous set of receivers. The objective is to design a low-cost multicast tree from the source that would provide the QoS levels (e.g., bandwidth) requested by the receivers. We assume that the QoS level required on a link is the maximum among the QoS levels of the receivers that are connected to the source through the link. In accordance, we define the cost of a link to be a function of the QoS level that it provides. This definition of cost makes this optimization problem more general than the classical Steiner tree problem. We consider several variants of this problem all of which are proved to be NP-Hard. For the variant where QoS levels of a link can vary arbitrarily and the cost function is linear in its QoS level, we give a heuristic that achieves a multicast tree with cost at most a constant times the cost of an optimal multicast tree. The constant depends on the best constant approximation ratio of the classical Steiner tree problem. For the more general variant, where each link has a given QoS level and cost we present a heuristic that generates a multicast tree with cost O(min {log r, k}) times the cost of an optimal tree, where r denotes the number of receivers, and k denotes the number of different levels of QoS required. We generalize this result to hold for the case of many multicast groups.

A QoS multicast routing protocol for dynamic group topology

Multicast routing is establishing a tree which is rooted from the source node and contains all the multicast destinations. A multicast routing tree with multiple QoS constraints may be the tree in which the delay, delay-jitter, packet-loss and bandwidth should satisfy the pre-specified bounds. This paper discusses the multicast routing problem with multiple QoS constraints, which may deal with the delay, delay-jitter, bandwidth and packet-loss metrics, and describes a network model for researching the routing problem. It presents a QoS multicast routing protocol with dynamic group topology (QMRPD). The QMRPD attempts to significantly reduce the overhead of constructing a multicast tree with multiple QoS constraints. In MPRMQ, a multicast group member can join or leave a multicast session dynamically, which should not disrupt the multicast tree. It also attempts to minimize overall cost of the tree, and satisfy the multiple QoS constraints and least cost's (or lower cost) requirements. In this paper, the proof of correctness and complexity analysis of the QMRPD are also given. Simulation results show that QMRPD is an available approach to multicast routing decision with dynamic group topology.

Minimum-cost QoS multicast and unicast routing in communication networks

In this paper, we study the minimum-cost quality-of-service multicast and unicast routing problems in communication networks. For the multicast problem, we present an efficient approximation algorithm to find a balance between a minimum-cost multicast tree and a minimum-delay multicast tree, with a provably good performance under the condition that link delay and link cost are identical. For the unicast problem, we present an efficient primal-dual heuristic algorithm to find a path which balances path cost and path delay, together with an error bound. The lack of a provably good performance for the second algorithm is complemented by computational results on randomly generated networks. Our algorithm finds optimal solutions in more than 80% of the cases and finds close to optimal solutions in all other cases, while using much less time.

An Adaptive Multicast Tree with QoS Support for Heterogeneous Recipients

This paper proposes a new protocol called MQ, Multicast with QoS, which supports multimedia group communications with QoS guarantees for heterogeneous recipients. With MQ, while resource reservation is de-coupled from QoS multicast routing, they are integrated in a way to avoid the problem of "sender-oriented" path determination, a problem that occurs when RSVP is used in conjunction with QoS routing for heterogeneous reservations. Being a truly receiver-oriented and integrated scheme for multimedia multicasting, MQ supports such integration in a robust, scalable and loop-free way, accommodates heterogeneous users with varied QoS, dynamically adjusts QoS trees to improve resource utilization, and benefits from being an integrated mechanism to ensure end-to-end QoS services. We have also conducted simulations to evaluate the performance of MQ. MQ demonstrates its advantages to conventional loosely coupled integration of IP multicasting, resource reservation and QoS routing, in terms of better accommodation of heterogeneous users, higher scalability, lower blocking probability for users to join groups with service guarantee, and more efficient resource utilization to enhance system performance.

QoS-guaranteed one-to-many and many-to-many multicast routing

Quality-of-service (QoS) multicast routing with more than one metric has always been technically challenging, since many of them are NP-hard. Most existing QoS multicast routing algorithms are heuristic. Furthermore, many of them considered only the unicast shortest paths, either based on propagation delay or the number of hops. The first part of this paper deals with one-to-many multicast routing. We observed that the end-to-end delay experienced by network packets is determined not only by the propagation distance, but also (and in many cases largely) by the hop-by-hop transmission and queuing delay, which in turn depends on the available bandwidth. Based on this observation, we propose an optimal multicast routing algorithm (the MBDC algorithm), which maximizes the reserved bandwidth while satisfying both delay and bandwidth constraints. Its correctness and time complexity of O( n 2 log n) are formally verified, where n is the number of nodes in the network. We also extend the algorithm to support dynamic membership, allowing nodes to join or leave the network, with the cast route updated dynamically. We carefully evaluate both the static and the dynamic algorithms via simulation. The second part of the paper focuses on minimizing the number of centers of multiple-shared multicast trees (MSMT) in many-to-many multicast routing. We propose three heuristic algorithms to this NP-complete problem and compare them with an existing one. We prove, theoretically and through simulation, that our algorithms give the same good results with a significantly shorter running time. We also apply the MBDC extension to the MSMT algorithms, so that the resulting solution not only reduces the number of centers, but also optimizes (maximizes) the bottleneck bandwidth. Proof of correctness, analysis of run-time, and simulation results of these extensions are also provided. We believe that the results report here are significant to the area of QoS-aware multicast routing; the algorithms may be applied to the Internet intra- and inter-domain multicast routing with minimal changes.

A fuzzy genetic algorithm for QoS multicast routing

It is impossible for nodes in an actual dynamic network to maintain the global accurate network state information. Therefore, it is unreasonable and inefficient to express the QoS constraints with deterministic crisp values. In this paper, the QoS multicast routing problem is solved by use of the generalized fuzzy-constrained fuzzy-optimization model. Both imprecision of the network state information and the fuzziness of QoS constraints are taken into account invoking fuzzy set theory. A new fuzzy genetic algorithm for QoS multicast routing is also presented and simulation experiments demonstrate that the algorithm is efficient.

MQ: an integrated mechanism for multimedia multicasting

This paper studies the integration of multimedia multicasting, with the consideration of multicast with end-to-end QoS guarantees by resource reservation, dynamic join and departure of participants, user heterogeneity, scalability, robustness, and loop-free control. A protocol called MQ, Multicast with QoS, is proposed to support multimedia group communications with QoS guarantees for heterogeneous recipients. With MQ, while resource reservation is de-coupled from QoS multicast routing, they are integrated in a way to avoid the problem of sender-oriented path determination, a problem that occurs when RSVP is used in conjunction with QoS routing for heterogeneous reservations. Being a truly receiver-oriented and integrated scheme for multimedia multicasting, MQ supports such integration in a robust, scalable and loop-free way. It also accommodates heterogeneous users with varied QoS, dynamically adjusts QoS trees to improve resource utilization, and guarantees end-to-end QoS requirements. We have conducted simulations to evaluate the performance of the proposed mechanism. MQ demonstrates its advantages over the conventional loosely coupled integration of TP multicasting, resource reservation and QoS routing, in terms of better accommodation of heterogeneous users, higher scalability, lower blocking probability for users to join groups with service guarantees, and more efficient resource utilization to enhance system performance.

Optimization of wavelength assignment for QoS multicast in WDM networks

This paper discusses quality-of-service (QoS) multicast in wavelength-division multiplexing (WDM) networks. Given a set of QoS multicast requests, we are to find a set of cost suboptimal QoS routing trees and assign wavelengths to them. The objective is to minimize the number of wavelengths in the system. This is a challenging issue. It involves not only optimal QoS multicast routing, but also optimal wavelength assignment. Existing methods consider channel setup in WDM networks in two separate steps: routing and wavelength assignment, which has limited power in minimizing the number of wavelengths. In this paper, we propose a new optimization method, which integrates routing and wavelength assignment in optimization of wavelengths. Two optimization algorithms are also proposed in minimizing the number of wavelengths. One algorithm minimizes the number of wavelengths through reducing the maximal link load in the system; while the other does it by trying to free out the least used wavelengths. Simulation results demonstrate that the proposed algorithms can produce suboptimal QoS routing trees and substantially save the number of wavelengths.