On max-min fair congestion control for multicast ABR service in ATM

In the ATM Forum activities, considerable efforts have focused on the congestion control of point-to-point available bit rate (ABR) service. We present a novel approach that extends existing point-to-point (unicast) congestion control protocols to a point-to-multipoint (multicast) environment. In particular, we establish a unified framework to derive a multicast congestion control protocol for an ABR service from a given rate-based unicast protocol. We generalize a known necessary and sufficient condition on the max-min fairness of unicast rate allocation for a multicast service. Using this condition, we show that the resulting multicast protocol derived using our framework preserves the fairness characteristics of the underlying unicast protocol. The practical significance of our approach is illustrated by extending a standard congestion control mechanism for an ABR service to a multicast environment. The performance of the resulting multicast protocol is examined using benchmark network configurations suggested by the traffic management subworking group at the ATM Forum, and simulation results are presented to substantiate our claims     

Fair Bandwidth Allocation Using Effective Multicast Traffic Share in TDM-PONs

In this paper, the effects of optical traffic-sharing on the performance of multicast video delivery in terms of the efficiency of bandwidth allocation and the fairness of link-sharing are discussed for the downstream direction of a time-division-multiplexed passive optical network (TDM-PON). We analyze the practical issues associated with multicast packet switching and transmission control in a TDM-PON and also propose a fair bandwidth allocation mechanism, called share-based proportional bandwidth allocation (S-PBA), to effectively support multicast services. In order to provide an optical network unit with a fair amount of link bandwidth and high throughput independent of traffic type, S-PBA arbitrates the amount of unicast timeslot by using effective multicast traffic share, which is determined based on multicast traffic load distribution and traffic-sharing density. Analytic and simulation results clearly validate the effectiveness of the proposed mechanism. This work is applicable to multicast video delivery or multicast traffic transmission in general, such as voice traffic, or a combination of both in the case of video conferencing, for example.     

Design and evaluation of multicast GFR for supporting TCP/IP over hybrid wired/wireless ATM

The major challenges of designing multicast traffic control protocols for a combined wired/wireless network are the varying transmission characteristics (bandwidth, error, and propagation delay) of the wireless and wired media, and the different, possibly conflicting frame rate requests from multiple sources. To address these issues, in this paper we design and evaluate new unicast and multicast guaranteed frame rate (GFR) schemes for supporting TCP/IP traffic over a combined wired/wireless ATM network. We first propose a new, flexible weighted buffer management, and a frame‐based virtual spacing (VS) mechanism implementing weighted fair queueing. The unicast GFR scheme is based on the integration of the new weighted buffer management, and either cell‐based or frame‐based VS. It is then extended to support multicast GFR flows. The multicast scheme presented in this paper is the first multicast GFR scheme appeared in the literature. These schemes are carefully evaluated over several network configuration, supporting heterogeneous TCP/IP traffic with various frame rates. Simulation results show that the new schemes guarantee the minimum rates requested, provide excellent fairness, and achieve reasonably high efficiency. The new schemes may be extended to provide differentiated service in both IP and mobile IP frame work. This revised version was published online in July 2006 with corrections to the Cover Date.     

Priority differentiated multicast flow scheduling method in Ceph cloud storage network

In order to solve the problem that existing flow scheduling method is difficult to meet the different multicast scheduling requirements of multi-service flows in the Ceph cloud storage network,a service priority-based multicast flow scheduling method was tailored.First,the network status was obtained via software defined network (SDN) to support flow scheduling.Then,a multicast task was decomposed into multiple attribute decision problems for multiple unicast path selection,and a method of unicast path selection based on technique for order preference by similarity to ideal solution (TOPSIS) was proposed.The unicast path selection method was used to find the optimal unicast path set for the service flow based on the flow’s network performance requirements.Then,the multicast distribution node was determined by the maximum common sub-path among the optimal unicast path sets for construct a multicast transmission path.The experiment results show that the proposed method can reduce the transmission delay of high priority flows while reduce the redundant traffic and better balance the traffic loads compared with the existing methods.     

Efficient cross-layer protocol for bandwidth-satisfied multicast in multi-rate MANETs

Since the multi-rate enhancements have been implemented in 802.11 wireless networks, QoS-constrained multicast protocols for multimedia communication should be adapted to exploit them fully. This work proposes a multicast protocol for data rate selection and bandwidth-satisfied multicast tree determination with an efficient cross-layer design based on the integration of PHY and MAC layers into the network layer. To use bandwidth efficiently and increase network capacity (which is the number of multicast flows supported by the network), we aim to select the combination of data rates and a multicast tree whose total amount of bandwidth consumption to the network is minimal in order to maximize the network capacity. The performance of the proposed protocol is compared with two existing protocols. Simulation results indicate that the proposed protocol has the ability to admit more multicast flows.     

Busy tone contention protocol: a new high‐throughput and energy‐efficient wireless local area network medium access control protocol using busy tone

Design of an efficient wireless medium access control (MAC) protocol is a challenging task due to the time‐varying characteristics of wireless communication channel and different delay requirements in diverse applications. To support variable number of active stations and varying network load conditions, random access MAC protocols are employed. Existing wireless local area network (WLAN) protocol (IEEE 802.11) is found to be inefficient at high data rates because of the overhead associated with the contention resolution mechanism employed. The new amendments of IEEE 802.11 that support multimedia traffic (IEEE 802.11e) are at the expense of reduced data traffic network efficiency. In this paper, we propose a random access MAC protocol called busy tone contention protocol (BTCP) that uses out‐of‐band signals for contention resolution in WLANs. A few variants of this protocol are also proposed to meet the challenges in WLAN environments and application requirements. The proposed BTCP isolate multimedia traffics from background data transmissions and gives high throughput irrespective of the number of contending stations in the network. As a result, in BTCP, admission control of multimedia flows becomes simple and well defined. Studies of the protocol, both analytically and through simulations under various network conditions, have shown to give better performance in comparison with the IEEE 802.11 distributed coordination function. Copyright © 2011 John Wiley & Sons, Ltd.     

Analytical evaluation of multicast packet delivery and user-clustering schemes in high-speed cellular networks

Transmission on data-oriented radio interfaces of cellular networks has been primarily designed for unicast applications. Nevertheless, unicast may not optimize the resource usage when the same content has to be transmitted to several users in the same cell. In this context, multicast seems to be an efficient means to convey data. In this paper, we develop an analytical model that allows the computation of the mean bitrate for both multicast and multiple-unicast transmission schemes. Furthermore, we propose a multicast transmission scheme called the equal-bitrate (EB) algorithm that allocates bandwidth to mobiles according to their instantaneous channel quality. We compare it to adaptations of the well-known max-signal-to-noise ratio and round robin to multicast. We propose to group users into clusters. The clustering method combines multicast and unicast transmission schemes according to the user’s average channel conditions. We use the analytical model to evaluate the proposed solutions. We compare the resulting performance against pure multicast and multiple-unicast approaches. We show that the EB algorithm offers a good trade-off between throughput and fairness. Also, we show that mixed clustering achieves good performance compared to conventional clustering methods.     

Performance evaluation of legacy QCN for multicast and multiple unicast traffic transmission

A multicast congestion control scheme is an interesting feature to control group communication applications such as teleconferencing tools and information dissemination services. This paper addresses a comparison between multiple unicast and multicast traffic congestion control for Carrier Ethernet. In this work, we proposed to study the quantized congestion notification (QCN), which is a layer 2 congestion control scheme, in the case of multicast traffic and multiple unicast traffic. Indeed, the QCN has recently been standardized as the IEEE 802.1Qau Ethernet Congestion Notification standard. This scheme is evaluated through simulation experiments, which are implemented by the OMNeT++ framework. This paper evaluates the reaction point start time congestion detection, feedback rate, loss rate, stability, fairness and scalability performance of the QCN for multicast traffic transmission and multiple unicast traffic transmission. This paper also draws a parallel between QCN for multicast traffic transmission and that for multiple unicast traffic transmission. Despite the benefit of integrating the multicast traffic, results show that performance could degrade when the network scales up. The evaluation results also show that it is probable that the feedback implosion problem caused by the bottlenecks could be solved if we choose to set the queue parameter Qeq threshold value at a high value, 75% of the queue capacity for instance. Copyright © 2016 John Wiley & Sons, Ltd.     

Bandwidth-allocation policies for unicast and multicast flows

Using multicast delivery to multiple receivers reduces the aggregate bandwidth required from the network compared to using unicast delivery to each receiver. However, multicast is not yet widely deployed in the Internet. One reason is the lack of incentive to use multicast delivery. To encourage the use of multicast delivery, we define a new bandwidth-allocation policy, called LogRD, taking into account the number of downstream receivers. This policy gives more bandwidth to a multicast flow as compared to a unicast flow that shares the same bottleneck, without starving the unicast flows, however. The LogRD policy also provides an answer to the question on how to treat a multicast flow compared to a unicast flow sharing the same bottleneck. We investigate three bandwidth-allocation policies for multicast flows and evaluate their impact on both receiver satisfaction and fairness using a simple analytical study and a comprehensive set of simulations. The policy that allocates the available bandwidth as a logarithmic function of the number of receivers downstream of the bottleneck achieves the best tradeoff between receiver satisfaction and fairness     

Optimized multipath network coding in lossy wireless networks

Network coding has been a prominent approach to a series of problems that used to be considered intractable with traditional transmission paradigms. Recent work on network coding includes a substantial number of optimization based protocols, but mostly for wireline multicast networks. In this paper, we consider maximizing the benefits of network coding for unicast sessions in lossy wireless environments. We propose Optimized Multipath Network Coding (OMNC), a rate control protocol that dramatically improves the throughput of lossy wireless networks. OMNC employs multiple paths to push coded packets to the destination, and uses the broadcast MAC to deliver packets between neighboring nodes. The coding and broadcast rate is allocated to transmitters by a distributed optimization algorithm that maximizes the advantage of network coding while avoiding congestion. With extensive experiments on an emulation testbed, we find that OMNC achieves more than two-fold throughput increase on average compared to traditional best path routing, and significant improvement over existing multipath routing protocols with network coding. The performance improvement is notable not only for one unicast session, but also when multiple concurrent unicast sessions coexist in the network.     

Multicasting with Localized Control in Wireless Ad Hoc Networks

This paper investigates how to support multicasting in wireless ad hoc networks without throttling the dominant unicast flows. Unicast flows are usually congestion-controlled with protocols like TCP. However, there are no such protocols for multicast flows in wireless ad hoc networks and multicast flows can therefore cause severe congestion and throttle TCP-like flows in these environments. Based on a cross-layer approach, this paper proposes a completely-localized scheme to prevent multicast flows from causing severe congestion and the associated deleterious effects on other flows in wireless ad hoc networks. The proposed scheme combines the layered multicast concept with the routing-based congestion avoidance idea to reduce the aggregated rate of multicast flows when they use excessive bandwidth on a wireless link. Our analysis and extensive simulations show that the fully-localized scheme proposed in this paper is effective in ensuring the fairness of bandwidth sharing between multicast and unicast flows in wireless ad hoc networks.     

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.     

Optimal multicast smoothing of streaming video over the Internet

A set of applications such as Internet video broadcasts, corporate telecasts, and distance learning require the simultaneous streaming of video to a large population of viewers across the Internet. The high bandwidth requirements and the multi-timescale burstiness of compressed video make it a challenging problem to provision network resources for streaming multimedia. For such applications to become affordable and ubiquitous, it is necessary to develop scalable techniques to efficiently stream video to a large number of disparate clients across a heterogeneous Internet. In this paper, we propose to multicast smoothed video over an application-level overlay network of proxies, and to differentially cache the video at the intermediate nodes (proxies) in the distribution tree, in order to reduce the network bandwidth requirements of video dissemination. We formulate the multicast smoothing problem as an optimization problem, and develop an algorithm for computing the set of transmission schedules for the tree that minimize the peak rate and rate variability, given buffer constraints at different nodes in the tree. We also develop an algorithm to compute the minimum buffer allocation in the entire tree, such that feasible transmission to all the clients is possible, when the tree has heterogeneous rate constraints. We show through trace-driven simulations that substantial benefits are possible from multicast smoothing and differential caching, and that these gains can be realized even with modest proxy caches.     

Ad Hoc网络中基于协商机制的QoS多播路由研究

针对移动Ad Hoc网络QoS多播路由中普遍存在的拥塞问题,提出了一种基于协商机制的QoS多播路由协议,节点协商使用以一定QoS约束建立起的多播链路,避免过度使用多播资源引起网络拥塞,从而提高分组投递率和网络吞吐量。通过NS2仿真证明,该协议能够保证不同类型业务在网络中传输的服务质量,提高网络的利用率。     

Congestion control for fair resource allocation in networks with multicast flows

We consider the problem of congestion control in networks which support both multirate multicast sessions and unicast sessions. We present a decentralized algorithm which enables the different rate-adaptive receivers in different multicast sessions to adjust their rates to satisfy some fairness criterion. A one-bit ECN marking strategy to be used at the nodes is also proposed. The congestion-control mechanism does not require any per-flow state information for unicast flows at the nodes. At junctions nodes of each multicast tree, some state information about the rates along the branches at the node may be required. The congestion-control mechanism takes into account the diverse user requirements when different receivers within a multicast session have different utility functions, but does not require the network to have any knowledge about the receiver utility functions.     

Multicast Link Adaptation in Reliable Transmission Over Geostationary Satellite Networks

The exploitation of fluctuating channel conditions in link adaption techniques for unicast transmission has been shown to provide large system capacity gains. However, the problem of choosing transmission rates for multicast transmission has not been thoroughly investigated. In this paper, we investigate multicast adaptive techniques for reliable data delivery in GEO satellite networks. An optimal multicast link adaptation is proposed with the aim to maximise terminal throughput whilst increasing resource utilization and fairness in the face of diverse channel conditions. Via simulation results and theoretical analysis, the proposed algorithm has shown to outperform other alternative multicast link adaptation techniques especially when the terminals are in vigorous channel conditions.     

The impact of multicast layering on network fairness

Many definitions of fairness for multicast networks assume that sessions are single rate, requiring that each multicast session transmits data to all of its receivers at the same rate. These definitions do not account for multirate approaches, such as layering, that permit receiving rates within a session to be chosen independently. We identify four desirable fairness properties for multicast networks, derived from properties that hold within the max-min fair allocations of unicast networks. We extend the definition of multicast max-min fairness to networks that contain multirate sessions, and show that all four fairness properties hold in a multirate max-min fair allocation, but need not hold in a single-rate max-min fair allocation. We then show that multirate max-min fair rate allocations can be achieved via intra-session coordinated joins and leaves of multicast groups. However, in the absence of coordination, the resulting max-min fair rate allocation uses link bandwidth inefficiently, and does not exhibit some of the desirable fairness properties. We evaluate this inefficiency for several layered multirate congestion control schemes, and find that, in a protocol where the sender coordinates joins, this inefficiency has minimal impact on desirable fairness properties. Our results indicate that sender-coordinated layered protocols show promise for achieving desirable fairness properties for allocations in large-scale multicast networks     

Fairness and Dynamic Flow Control in Both Unicast and Multicast Architecture Networks

With the development of multicast service in the Internet, much attention has been drawn to multicast congestion control and analysis. Multicast traffic poses new challenges to the design of Internet congestion control protocols and system stability analysis. The rate control problem of feedback-based sessions on the coexistence of both unicast and multirate multicast traffic architecture networks is focused upon in this paper. First, a fairness problem is discussed in detail, and a reasonable consumption strategy is proposed. In the reasonable consumption strategy, scaling functions are adaptively adjusted based on a relationship between the session rates. Second, contraposing the case that available link capacities are changing with time for these feedback-based unicast and multicast sessions, stability analysis of a closed-loop rate control system under the modified rate mechanism is made based on Lyapunov stable theory. Finally, the simulations illustrate the effectiveness and goodness of the reasonable consumption strategy     

基于H.332的IP组播多媒体会议系统的研究与实现

本文研究了基于Ｈ．３３２协议的分布式松耦合会议系统的模型和优点,设计并实现了基于Ｈ．３３２的ＩＰ组播多媒体会议系统。该系统利用时间戳、序列号和同步源标记实现了音频、视频的同步、错序纠正和多路音频、视频的区别、通过视频的分层编码和多层组播传输实现了流量控制。与ＩＰ单播多媒体会议系统的对比实验表明,基于Ｈ．３３２的ＩＰ组播多媒体会议系统具有规模扩展性强、资源利用率高等优点。     

Analysis of tree‐based multicast routing in wireless sensor networks with varying network metrics

Wireless ad hoc and sensor networks are emerging with advances in electronic device technology, wireless communications and mobile computing with flexible and adaptable features. Routing protocols act as an interface between the lower and higher layers of the network protocol stack. Depending on the size of target nodes, routing techniques are classified into unicast, multicast and broadcast protocols. In this article, we give analysis and performance evaluation of tree‐based multicast routing in wireless sensor networks with varying network metrics. Geographic multicast routing (GMR) and its variations are used extensively in sensor networks. Multicast routing protocols considered in the analytical model are GMR, distributed GMR, demand scalable GMR, hierarchical GMR, destination clustering GMR and sink‐initiated GMR. Simulations are given with comparative analysis based on varying network metrics such as multicast group size, number of sink nodes, average multicast latency, number of clusters, packet delivery ratio, energy cost ratio and link failure rate. Analytical results indicate that wireless sensor network multicast routing protocols operate on the node structure (such as hierarchical, clustered, distributed, dense and sparse networks) and application specific parameters. Simulations indicate that hierarchical GMR is used for generic multicast applications and that destination clustering GMR and demand scalable GMR are used for distributed multicast applications. Copyright © 2012 John Wiley & Sons, Ltd.