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Well-known issues with multicast have prevented the deployment of multicast in 802.11 and other local-area wireless environments. This document offers guidance on known limitations and problems with wireless multicast. Also described are certain multicast enhancement features that have been specified by the IETF and by IEEE 802 for wireless media, as well as some operational choices that can be taken to improve the performace of the network. Finally, some recommendations are provided about the usage and combination of these features and operational choices.

The chapter describes an architecture to relay on demand a real-time IP multicast audio-video stream broadcasted by a satellite on a terrestrial link. The stream is received by suitably equipped sites and then relayed to other sites that are not equipped with satellite receiving hardware but are nonetheless willing to receive the stream. By exploiting the properties of satellite transmission and adopting a hybrid satellite/terrestrial, multicast/unicast approach, the described architecture allows to overcome the restrictions suffered by multicast traffic in the global Internet, allowing it to scale easily across autonomous systems. All things considered, the proposed architecture outlines a large-scale interactive audio-video distribution system similar to those based on Content Distribution Networks (CDNs) and it compares favourably with them when performances, costs and scalability are examined.

This document specifies a network proxy that uses Multicast DNS to automatically populate the wide-area unicast Domain Name System namespace with records describing devices and services found on the local link.

The network-on-chip (NoC) has been introduced as an efficient communication backbone to tackle the increasing challenges of on-chip communication. Nevertheless, merely metal-based NoC implementation offers only limited performance and power scalability in terms of multicast and broadcast traffics. To meet scalability demands, this paper addresses the system-level challenges for intra-chip multicast communication in a proposed hybrid interconnects architecture. This hybrid NoC combines and utilizes both regular metal on-chip interconnects and new type of wireless-NoC (WiNoC) which is Zenneck surface wave interconnects (SWI). Moreover, this paper embeds novel multicast routing and arbitration schemes to address system-level multicast-challenges in the proposed architecture. Specifically, a design exploration of contention handling in SWI layer is considered in both centralized and decentralized manners. Consequently, the hybrid wire-SWI architecture avoids overloading the network, alleviates the formation of traffic hotspots and avoid deadlocks that are typically associated with state-of-the-art multicast handling. The evaluation is based on a cycle-accurate simulation and hardware description. It demonstrates the effectiveness of the proposed architecture in terms of power consumption (up to around $10$ x) and performance (around $22$ x) compared to regular NoCs. These results are achieved with negligible hardware overheads. This study explore promising potential of the proposed architecture for current and future NoC-based many-core processors.

For reliable multicasting, packet retransmission is an important mechanism in ensuring lossless data delivery. Existing packet retransmission methods cannot effectively address the recovery redundancy problem. This paper presents an OpenFlow-enabled elastic loss recovery solution, called ECast, for reliable multicasting. It employs a novel communication method, called elastic area multicast (EAM), to better retransmit the multicast recovery packets in OpenFlow-enabled networks. With the flexible flow-matching ability of OpenFlow switches, any subtree of a multicast tree can be used as an EAM tree. EAM approximately implements an elastic local multicast. Therefore, it can effectively alleviate the recovery redundancy with good scalability. We introduce an optimal EAM-based packet retransmission orchestration problem, named outdegree-constrained minimum-cost loss recovery (OCMCLR), which finds the EAM-based packet retransmission scheme with the minimum recovery cost. ECast uses an optimized tree-based feedback method to obtain the status of packet losses, and uses a fast cluster-based algorithm to approximately solve the OCMCLR problem based on the collected packet loss status.

Scalable video coding is a promising technique to enable flexible video transmission for heterogeneous terminals and varying channel throughput. However, it is challenging to perform in-network adaptation in conventional networks because the network nodes are uncontrollable and transparent for media streaming applications. Software-defined networking (SDN) is an attractive network technology that supports the applications to collaborate with network nodes to achieve intelligent and dynamic service provisioning. Against this changing network landscape, we redesign the scalable multimedia multicast streaming by exploiting the complete network knowledge of the SDN controller to enable intelligent scalable video transmission. The proposed scalable multimedia multicast streaming framework is capable of in-network identifying, processing, and manipulating the media streams. In order to achieve the in-network adaptation, we apply equivalent bandwidth theory to estimate the affordable video layers that a link may accommodate, and apply finite-state machine to implement adaptive enhancement layer switching for multicast paths. In contrast to IP multicast, the proposed method is a controllable multicast scheme, which provides admission control in a multicast context, in-network adaptation, and supporting heterogeneous devices having different display capability. We further implement a prototype for illustrating the success of the proposed solution. The experimental results are also presented to show the effectiveness of the proposed equivalent bandwidth based adaptive enhancement layer switching algorithm.

Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud federation. Data transmissions required for inter-cloud federation in the complex inter-cloud networking system are often point-to-multi points, which calls for a more effective and efficient multicast routing algorithm in complex networking systems. In this paper, we investigate the multicast routing problem in the inter-cloud context with K constraints where K U+2265 2. Unlike most of existing algorithms that are too complex to be applied in practical scenarios, a novel and fast algorithm for establishing multicast routing tree for interclouds is proposed. The proposed algorithm leverages an entropybased process to aggregate all weights into a comprehensive metric, and then uses it to search a multicast tree U+0028 MT U+0029 on the basis of the shortest path tree U+0028 SPT U+0029.We conduct complexity analysis and extensive simulations for the proposed algorithm from the approximation perspective. Both analytical and experimental results demonstrate that the algorithm is more efficient than a representative multi-constrained multicast routing algorithm in terms of both speed and accuracy, and thus we believe that the proposed algorithm is applicable to the inter-cloud environment.

Due to significant advances in wireless modulation technologies, some MAC standards such as 802.11a, 802.11b, and 802.11g can operate with multiple data rates for QoS-constrained multimedia communication to utilize the limited resources of MANETs more efficiently. In this paper, by means of measuring the busy/idle ratio of the shared radio channel, a method for estimating one-hop delay is first suggested. Then, by constructing a multicast tree, a delay-sensitive multicast protocol for real-time applications in multirate MANETs is proposed. In order to increase the network capacity, the proposed multicast protocol intends to minimize the sum of the total transmission time of the forwarders and the total blocking time of the blocked hosts, by taking the neighboring information of the forwarders into account and properly adjusting the data rates of the forwarders. Simulation results show that the proposed delay estimation method is more accurate, as compared with previous works. Besides, the proposed multicast protocol can induce higher network capacity, while satisfying the delay requirement.

Multicasting can reduce network traffic in multiuser systems by serving multiple users simultaneously. The benefits of multicasting basically come from the overlapping and synchronism of user requests. Pushing and caching are techniques that prestore content items in buffers closer to users based on the prediction of user requests, thereby providing a promising approach to eliminating the asynchronism of user requests and creating multicasting opportunities. This paper studies a multiuser wireless communication system, in which the buffers for caching are deployed in the user terminals. Based on the request delay information (RDI) which describes when the users request content items in a deterministic or statistical way, a joint pushing and caching (JPC) method is presented to schedule the content items pushed by the base station and cached in the user buffers. In this paper, multicasting JPC systems work in two modes, without or with the feedback of RDI. Furthermore, RDI is classified into three forms, namely, noncausal, statistical, and causal. Static and dynamic JPC policies are, respectively, proposed for the two work modes. In addition, the effective throughput resulting from JPC under the three forms of RDI is demonstrated via theoretical analysis and simulation.

We design and implement a practical layered multiplexed-coded decode-forward (LMDF) relaying strategy for a wide-band wireless multicast network. The proposed LMDF scheme relies on layering at the source, with the individual layers provided unequal power allocation through a simple bit-mapping operation to quadrature amplitude modulation constellations. At the relay, LMDF utilizes a multiplexed-coded approach that, with a single transmission, caters for the disparity in the number of layers decoded at different destinations. Under a practical setup of hard-decision decoding and coding across the subcarriers of orthogonal frequency division multiplexing (OFDM) modulated transmissions, we derive the information theoretic achievable rates of LMDF and use the IEEE 802.11 TGn channel model for performance evaluations. LMDF is then implemented using convolutional codes, with the relay's code optimized specifically keeping its multiplexed nature in mind. In addition to simulations, we also evaluate the performance of LMDF through a system-level implementation by using the National Instruments USRPs 2921. We conduct over-the-air experiments in an indoor office environment using an OFDM-based physical layer, and illustrate the considerable performance benefits of LMDF over benchmarks such as conventional two-hop decode-forward.

With the recent emergence of naked-eye 3D mobile devices and various 3D-enabled laptops, service providers now afford the opportunity to provide mobile 3D video streaming in LTE-Advanced networks. Differing from traditional single-view 3D videos, multi-view 3D videos allow users to choose preferred view angles and thus are promising for new applications, such as free-viewpoint television (FTV). Nevertheless, enabling multi-view 3D video services may overwhelm the network resource when transmitting all views of every video. Fortunately, Depth-Image-Based Rendering (DIBR) allows each mobile client to synthesize the desired view from a nearby left view and right view, so that not all views of a video are necessarily transmitted. A new challenge with DIBR, however, is to carefully choose the transmitted views to limit the video distortion and minimize the bandwidth consumption. In this paper, therefore, we first formulate a new optimization problem, called View and MCS Selection (VMS) Problem, to minimize the bandwidth consumption for multi-view 3D video multicast in LTE networks. An algorithm, called View and MCS Aggregation (VMAG) is proposed to find the optimal solution to VMS. For Carrier Aggregation (CA) in LTE-Advanced networks, we formulate a new View, MCS and Carrier Selection (VMCS) Problem and prove that the problem is NP-Hard. We first design a dynamic programming algorithm, called the View Assignment with MCS and Carrier (VAMC) algorithm, to find the optimal solution for small instances. We then propose the View and MCS Aggregation with Carrier (VMAGC) algorithm based on VMAG to effectively find the near-optimal solution to VMCS. The simulation results show that bandwidth consumption can be effectively reduced by over 30 percent in VMS and VMCS.

To support the massive content delivery, a novel virtualized heterogeneous network framework is proposed to enable content transcoding, caching, and multicast. In addition, a virtual multi-resources allocation problem is formulated to jointly optimize the utilities of computing, caching, and communication for the proposed framework. Simulations are conducted to show the effectiveness of the proposed scheme.

Wireless mesh networks (WMNs) connect to the Internet via access gateways. This paper studies multi-source video multicast in Internet-connected WMNs. The focus is on the design of a shareable integrated multicast that allows the multicasts of video sources to employ common Internet shortcuts or WMN paths to avoid potentially high WMN overheads and excessive Internet usage. Several algorithms are described that together form a video multicast framework running a controlled number of shareable multicasts under the constraint of Internet availability. These algorithms are the resource-efficient source group algorithm, the efficient integrated architecture algorithm, and the interference-controlled multicasting tree algorithm. These algorithms represent different approaches to overcoming various costs arising from multi-source video multicast, enabling multiple video sources to distribute delay, and throughput-guaranteed videos to receivers across large-scale areas. Simulation results are presented that quantify the performance gains that can be achieved.

It is a quite common case for Wireless Sensor Networks (WSNs) in most application scenarios, that the same message needs to be sent to multiple destinations from a single sensor node. These applications can benefit from the use of multicast communications to conserve resource. Multicast geographic routing has recently been proposed as an efficient and scalable approach to fulfill this requirement by exploiting the location information of nodes instead of the global topology information to route multicast messages. As the sensor nodes are often powered by batteries and recharging them is infeasible, energy-efficient routing plays an important role towards the success of WSNs. In this paper, we address this challenging issue of WSNs and propose an energy-efficient multicast geographic routing protocol (EMGR) to achieve this goal. EMGR employs an energy-aware multicast tree, formed by the set of destinations and the source node based on the metric of energy over advance, to guide multicast message delivery and adaptively select the nodes closest to the energy-optimal relay location as the next forwarders for energy conservation. Analytic and simulation results demonstrate that our proposed protocol achieves the improved performance in terms of low energy consumption, control overhead, computational complexity, and high packet delivery ratio, compared to the existing protocols.

Nowadays, Power Line Communication (PLC) technology is receiving a renewed attention for a wide class of innovative applications and services, mainly thanks to the advantage of using the existing electrical infrastructures, thus reducing the deployment costs. However, such electrical infrastructures have been originally conceived for power distribution and not for data. Hence, signal propagation is affected by more severe impairments than traditional media, such as impulsive noise and frequency selectivity. Furthermore, new emerging PLC applications need more efficient information delivery schemes that encompass both unicast and multicast mode. Towards this end, this paper deals with an efficient Network Coding (NC) based multicast reliable PLC scheme that makes use of (i) a decision direct impulsive noise mitigation approach and of (ii) a scheme based on multiple transmissions of a same symbols in the frequency domain. A suitable optimization procedure is also proposed here with the aim of improving the performance of the proposed scheme, under the constraint of a specified maximum data flow delivery failure probability. Finally, comparisons with alternative solutions are provided in order to highlight the significant advantages of the proposed scheme in terms of data flow delivery delay and overall transmission energy cost, under specific service constraints.

This paper designs a novel non-orthogonal multiple access (NOMA) unicast–multicast system, where a number of unicast users (those who require different messages) and a group of multicast users (those who require identical message) share the same time/space/frequency resource. For the designed NOMA unicast–multicast system, an efficient two-phase cooperation strategy is proposed to improve the reliability of all users. In the first phase, the base station (BS) broadcasts a superposed message consisting of all users’ information. In the second phase, a multicast user is selected to forward the information intended by unsuccessfully decoded unicast and/or multicast users. Moreover, the multicast user selection is investigated under two different power allocation (PA) approaches: 1) fixed PA (FPA), in which the PA coefficients for both the phases are predetermined, and 2) dynamic PA (DPA), in which the PA coefficients for the first phase are predetermined, while the PA coefficients for the second phase are dynamically determined based on instantaneous channel information. Under the FPA approach, a best user selection (BUS) scheme (called F-BUS) is proposed to minimize the outage probability. Under the DPA approach, the local optimal PA coefficients for the second phase are derived in closed form first. Based on the derived PA coefficients, a BUS scheme (called D-BUS) is then proposed for outage probability minimization. To verify the reliability of the proposed cooperation strategy with employing the BUS schemes, we theoretically analyze the outage probability as well as diversity orders. It is shown that the proposed cooperation strategy achieves diversity orders equal to the number of multicast users, indicating that the inherent diversity orders offered by the multicast users are fully exploited. Finally, simulation results are presented to validate the theoretical results and demonstrate the advantages of the proposed cooperation strategy and the BUS schemes.

eXplicit multicasting (Xcast) is a protocol to send data to multiple receivers in an efficient way. Compared with traditional stateful multicast, Xcast is based on a stateless approach that scales better in number of groups. Unfortunately, the original Xcast brings up new challenges such as the scalability of group size and efficiency issue. Therefore, Multiple Xcast (MXcast) and Generalized Xcast (GXcast) were proposed to retard the limitation of the group size by reconstructing the multicast group into multiple subgroups and transferring multiple Xcast packets to different subgroups, respectively. In this paper, we propose various subgrouping schemes and evaluate their performance based on hybrid simulation experiments. The results show that it can save up to 36.7% bandwidth consumption from Xcast to our proposed Optimal GXcast in Voice over Internet Protocol (VoIP). The results reflect that the proposed scheme can improve the scalability of group size, achieve minimal packet delivery latency, reduce both network bandwidth consumption and source loading compared with the unicast and original Xcast, MXcast, and GXcast.

Multicast is an important way to diffuse data in duty-cycled wireless sensor networks (WSNs), where nodes can receive data only in active state. The communication delay can be extremely large if inappropriate schedules are adopted. Unfortunately, most previous methods do not consider controlling multicast delay energy-efficiently. This paper studies the minimum active time slot augmentation for delay-bounded multicast (MAADM) problem in duty-cycled WSNs. The MAADM problem is proved to be NP-hard even under the node-exclusive interference model. An optimal algorithm is proposed for the MAADM problem when $K=2$ and a heuristic latency bounding algorithm is proposed for source-to-all communications, where $K$ denotes the number of the destination nodes. When $K>2$ , two ( $K$ −1)-approximation algorithms are designed for the MAADM problem. In addition, a low computation-complexity distributed algorithm is proposed. To the best of our knowledge, this is the first work that develops a series of efficient centralized and distributed algorithms for the MAADM problem in duty-cycled WSNs. The theoretical analysis and experimental results verify that all the proposed algorithms have high performance in terms of delivery delay and energy consumption.

Buffered Clos-network switches have advantages of modularity and simplicity; however, they are limited to serious out-of-sequence problems, especially when serving multicast traffic. In this study, a frame-based multicast scheduling algorithm for memory-memory-memory Clos networks (FMClos) is proposed. Multicast cells are replicated at the first and last stages based on address-copy technology, which eliminates head-of-line (HoL) blocking and improves throughput performance. The frame-based scheduling scheme performed at the input module, as well as the buffered crossbar switch element adopted by the central module, contributes to reducing the out-of-sequence (OOS) cells. Simulation results show that FMClos scheme can achieve nearly 100% throughput. In comparison with existing algorithms, the proposed method decreases the proportion of OOS cells and considerably reduces resequencing delay under heavy traffic load.

Cognitive radio is a prominent technology for improving radio spectrum efficiency. In this paper, we study an underlay cognitive radio network (CRN), consisting of a cognitive base station (CBS) and multiple multicast group of secondary users (SUs). A common primary user (PU) channel is used to support multicast services to a group of SUs. Our objective is to minimize the outage probability of the SU multicast groups. The problem is formulated using constrained optimization framework under the constraints of PUs’ outage probability and CBS’s average transmit power. An efficient transmit power allocation scheme, which determines the optimal power for each SU multicast group, is proposed. Simulation results are presented to validate the proposed power allocation scheme, thereby improving the spectrum efficiency of the CRN.

Flex-grid optical networks based on orthogonal frequency division multiplexing support quite high bit rates (beyond 400 Gb/s). The flexible grid and elastic bandwidth allocation scheme of flex-grid...

Multicast is designed to jointly deliver content from a single source to a set of destinations; hence, it can efficiently save the bandwidth consumption and reduce the load on the source. In many important applications, the appearance of multiple sources brings new opportunities and challenges to reduce the bandwidth consumption of a multicast transfer. In this paper, we focus on such type of multi-source multicast and construct an efficient routing forest with the minimum cost (MCF). MCF spans each destination by one and only one source, while minimizing the total cost (i.e. the weight sum of all links in one multicast routing) for delivering the same content from the source side to all destinations. Prior approaches for single source multicast do not exploit the opportunities of a collection of sources; hence, they remain inapplicable to the MCF problem. Actually, the MCF problem for a multi-source multicast is proved to be NP-hard. Therefore, we propose two ( 2 + ɛ ) -approximation methods, named P-MCF and E-MCF. We conduct experiments on our SDN testbed together with large-scale simulations under the random SDN network, regular SDN network and scale-free SDN network. All manifest that our MCF approach always occupies fewer network links and incurs less network cost for any multi-source multicast than the traditional Steiner minimum tree (SMT) of any related single source multicast, irrespective of the used network topology and the setting of multicast transfers.

We consider the multicast scheduling problem in the heterogeneous network using a half-duplex relay station (RS). Our goal is to minimize the delay of transmitting a block of packets to users over time-varying channels using rateless codes. Due to half-duplex operation, at each time slot, the RS can choose to either multicast a packet to the users, or fetch a packet from the macro base station. We formulate a fluid relaxation for the optimal decision problem, and reveal that the optimal policy has a threshold-based structure so as to exploit the opportunism of multicast channel: the RS should multicast only when the channel quality is sufficiently “high”. We propose an online policy based on the relaxation which does not require the knowledge of channel distribution. When the channel distribution is symmetric across users, we provide a closed-form expression of the asymptotic performance of our policy. For two-user systems, we prove that our scheme is asymptotically optimal. When the users’ channels are independent, we derive a performance bound based on water-filling rate allocation which approximates the optimal policy well. Simulation results show that our scheme performs close to theoretical bounds, under correlated as well as independent fading channels.

Recently, the use of real-time multimedia applications has attracted the attention of mobile ad hoc network users. These applications support service quality. The characteristics of mobile ad hoc networks such as lack of central coordinator, mobility of hosts, dynamic changes in network topology and the limitation of access to resources have caused remarkable challenges in providing high quality services for mobile ad hoc networks. Bandwidth limitation of wireless nodes and the lack of adequate multicast trees are regarded as the main challenges for quality of service-based multicast routing. In this paper, an attempt was made to propose a more stable and more reliable in multi-path quality of service multicast routing protocol (SR-MQMR) for mobile ad-hoc networks. In the proposed method, considering the requested bandwidth, the researchers first used the signal strength of nodes to select the most stable nodes. Then, using the two parameters of route expiration time and the number of hops, we selected a route which had low delay and high stability. The results of simulations conducted in the present study indicated that the SR-MQMR protocol used less time slots than the MQMR protocol in the routing process which resulted in an increase in success ratio. Furthermore, the production of stable routes led to a significant enhancement of reliability. Since the reduction of route request packet exchange decreased overhead in the proposed method, the degree of consumed bandwidth decreased which led to an increase in network lifetime.

The quality of service multicast routing problem is a very important research issue for transmission in wireless mesh networks. It is known to be NP-complete problem, so many heuristic algorithms have been employed for solving the multicast routing problem. This paper proposes a modified binary bat algorithm applied to solve the QoS multicast routing problem for wireless mesh network which satisfies the requirements of multiple QoS constraints such as delay, delay jitter, bandwidth and packet loss rate to get low-cost multicasting tree. The binary bat algorithm has been modified by introducing the inertia weight w in the velocity update equation, and then the chaotic map, uniform distribution and gaussian distribution are used for choosing the right value of w. The aim of these modifications is to improve the effectiveness and robustness of the binary bat algorithm. The simulation results reveal the successfulness, effectiveness and efficiency of the proposed algorithms compared with other algorithms such as genetic algorithm, particle swarm optimization, quantum-behaved particle swarm optimization algorithm, bacteria foraging-particle swarm optimization, bi-velocity discrete particle swarm optimization and binary bat algorithm.

Multicasting is a useful network service in wireless mesh networks (WMNs) for delivering same data from a source to multiple destinations. An effective multicast routing protocol in multi-channel multi-radio WMNs (MCMR-WMNs) is required to satisfy the following criteria together: high network throughput, low end-to-end delay, low tree cost, low computational time, and load-aware routing. Furthermore, how to fully exploit channel diversity in MCMR-WMNs to accomplish low channel interference criteria is a critical issue in designing multicast routing protocol. In spite of its significance, multicast routing which satisfies all of the mentioned criteria, has not drawn much attention so far. Besides, major multicast routing protocols proposed in MCMR-WMNs are centralized or solve two problems of multicast tree construction and channel assignment sequentially. These protocols are time-consuming in addition to suffering from a single-point-of-failure. In this paper, we propose a distributed cross-layer algorithm for joint multicast routing and channel assignment in MCMR-WMNs. For the first time, we apply fuzzy credit assigned cerebellum model articulation controller (FCA-CMAC) neural network model to construct multicast routing tree considering load on the mesh nodes and the delay between neighboring mesh nodes. Moreover, we present a heuristic channel assignment algorithm aiming to reduce interference among the links of the multicast tree. FCA-CMAC converges quickly and creates minimal delay and load-aware multicast tree. Therefore, proposed method can optimize the network throughput, end-to-end delay, tree cost, and computational time. Additionally, channel assignment algorithm is subject to produce the minimal interference multicast tree. Simulation results show that in terms of aforementioned criteria, the proposed FCA-CMAC based multicast algorithm achieves better performance than those comparative references.

The tremendous energy consumption attributed to the Information and Communication Technology (ICT) field has become a persistent concern during the last few years, attracting significant academic and industrial efforts. Networks have begun to be improved towards being “green”. Considering Quality of Service (QoS) and power consumption for green Internet, a Green Intelligent flexible QoS many-to-many Multicast routing algorithm (GIQM) is presented in this paper. In the proposed algorithm, a Rendezvous Point Confirming Stage (RPCS) is first carried out to obtain a rendezvous point and the candidate Many-to-many Multicast Sharing Tree ( M 2 ST ); then an Optimal Solution Identifying Stage (OSIS) is performed to generate a modified M 2 ST rooted at the rendezvous point, and an optimal M 2 ST is obtained by comparing the original M 2 ST and the modified M 2 ST . The network topology of Cernet2, GeANT and Internet2 were considered for the simulation of GIQM. The results from a series of experiments demonstrate the good performance and outstanding power-saving potential of the proposed GIQM with QoS satisfied.

© 1967-2012 IEEE. Multicasting is emerging as an efficient method to deliver the same data to a group of users, thereby saving network resources. The fairness between different multicast groups is an important quality-of-service (QoS) indication, but it has not been given significant attention. In this paper, we propose a normalized signal-To-noise ratio (SNR)-based fair scheduling for multiple multicast groups in multicast systems. The system fairness and capacity are then analyzed and compared for both fair scheduling and greedy scheduling over independent but non-identically distributed (i.n.d.) fading channels. Closed-form expressions in terms of the system spectral efficiency, outage probability, system fairness, and average bit error rate (BER) are derived in an uncoded/coded M-Ary quadrature amplitude modulation based adaptive transmission multicast system over i.n.d. Rayleigh fading channels. Numerical results show that compared with greedy scheduling, fair scheduling achieves considerably high fairness at the cost of slight system capacity loss, regardless of the number of multicast groups. Our focus is on the physical layer without rate loss, but we also briefly discuss applications of the proposed scheduling in a cross-layer design subject to the loss rate QoS constraint.

The multicast framework that provides a network with multicast group management and a multicast routing algorithm is universal and exclusive, which leads to two shortcomings to multicast communication. First, the multicast framework’s default multicast routing algorithm is not specially designed for congestion avoidance, which negatively affects the quality of service (QoS) of multicast trees. Second, customized multicast routing algorithms cannot be deployed over the framework. Therefore, the multicast framework cannot simultaneously satisfy the QoS requirements of different application scenarios. To overcome these two drawbacks, we propose an innovative multicast framework that can be deployed in parallel with the existing multicast framework as a multicast plug-in for an SDN network operating system. This promising feature makes it possible to use customized multicast routing algorithms and maintain compatibility with typical multicast applications. Furthermore, based on this multicast framework, we propose a delay-constrained multicast routing algorithm that borrows ideas from anycast to actively avoid traffic congestion in multicast trees. Experimental results show that the framework is feasible and performs well, especially in high-load situations.

The 60-GHz bands target multi-gigabit rate applications, such as high definition video streaming. Unfortunately, to provide multicast service, the strong directionality required at 60 GHz precludes serving all clients in a multicast group with a single transmission. Instead, a multicast transmission is comprised of a sequence of beam-formed transmissions (a beam group) that together cover all multicast group members. In this paper, we design, implement, and experimentally evaluate scalable directional multicast (SDM) as a technique to 1) train the access point with per-beam per-client RSSI measurements via partially traversing a codebook tree. The training balances the objectives of limiting overhead with collecting sufficient data to form efficient beam groups. 2) Using the available training information, we design a scalable beam grouping algorithm that approximates the minimum multicast group data transmission time. We implement the key components of SDM and evaluate with a combination of over-the-air experiments and trace-driven simulations. Our results show that the gains provided by SDM increase with group size and provide near-optimal group selection with significantly reduced training time, yielding up to 1.8 times throughput gains over exhaustive-search training and grouping.

In recent years there has been an exponential increase in the growth in multimedia applications, and in particular in video applications. Understanding the behavior of the video traffic and the requirements for the network helps network administrators to improve the traffic. In this work, a quantitative analysis is performed by experimentation, in order to evaluate the behavior and impact of video traffic on WAN networks. We propose a WAN test bed with fourth subescenarios that allows to inject unicast or multicast video traffic, compressed with several codecs. The generic topology used includes a computer running as a streaming server and up to 20 desktop computers (PCs) as clients connected at the ends of a network as if outside a WAN. This network WAN is formed by routers and switchs with different types of links interconnecting the same. For the operation between routers was configured the OSPF routing protocol v2. For the same routers are configured the routing multicast protocol PIM in dense mode. From capturing video traffic, we identified several interesting performance and Qo metrics, such as unicast and multicast throughput, delay, jitter, and Pareto distribution. We include detailed contributions on the impact produced by several factors, such as the codec used for the compression, and the use of unicast and multicast traffic when there are restrictions on the bandwidth, as in a corporate real WAN link of some few Mbps. The work oriented on the configurations to be taken into account for an adequate management of similar networks and an efficient use of the resources available, without compromising the performance and the expected QoS. Besides facilitates the comparison of the results with those obtained from analytical studies and modelling for different contexts.

Continuously enriched distributed systems in data centers generate much network traffic in push-style one-to-many group mode, raising new requirements for multicast transport in terms of efficiency and robustness. Existing reliable multicast solutions, which suffer from low robustness and inefficiency in either host-side protocols or multicast routing, are not suitable for data centers. In order to address the problems of inefficiency and low robustness, we present a sender-initiated, efficient, congestion-aware and robust reliable multicast solution mainly for small groups in SDN-based data centers, called MCTCP. The main idea behind MCTCP is to manage the multicast groups in a centralized manner, and reactively schedule multicast flows to active and low-utilized links, by extending TCP as the host-side protocol and managing multicast groups in the SDN-controller. The multicast spanning trees are calculated and adjusted according to the network status to perform a better allocation of resources. Our experiments show that, MCTCP can dynamically bypass the congested and failing links, achieving high efficiency and robustness. As a result, MCTCP outperforms the state-of-the-art reliable multicast schemes. Moreover, MCTCP improves the performance of data replication in HDFS (Hadoop Distributed File System) compared with the original and TCP-SMO (an alternative reliable multicast scheme) based ones, e.g., achieves up to 1.5 × and 1.1 × improvements in terms of throughput, respectively.

Multicast communication is the concurrent transmission of data from one source node to many destination nodes. It is widely deployed in high performance computing and communication networks. In this article, wide-sense nonblocking multicast communication is studied in wavelength division multiplexing networks namely modified linear array, unidirectional and bidirectional modified ring networks. The sufficient and necessary condition on the minimum wavelength number required for the network to be wide-sense nonblocking is derived for each of the above network topologies under longest link first routing technique which employs approximately half the number of hops when compared with networks without modification. An explicit wavelength allotment technique for multicast assignment is also given for each of the above network topologies.

In-packet bloom filter based multicast is a family of techniques that have been recently proposed to address scalability issues in IP multicast. The main problem motivating these techniques is that network forwarding elements supporting traditional IP multicast store group specific forwarding state for every multicast tree traversing the element, resulting in poor memory scalability in networks with many active groups. Techniques in this family address this problem by encoding multicast routing information into in-packet bloom filters, which are memory efficient, probabilistic data structures for representing set membership. However, in existing approaches the probabilistic nature of bloom filters results in false-positive packet delivery, thereby introducing forwarding anomalies, unnecessary bandwidth utilization, and violations of security policies. In this work we contribute BloomFlow, a novel approach to bloom filter based multicast in SDN that achieves substantial forwarding state reduction while eliminating false positive packet delivery. The BloomFlow approach compensates for the stochastic uncertainty associated with bloom filters by incorporating the SDN network controller’s knowledge of the network topology and traffic workload into the generation of variable length and false-positive-free bloom filters. We further contribute a set of extensions to the OpenFlow protocol that demonstrates how our approach can be integrated into OpenFlow enabled networks with minimal modifications to switch hardware. We implement a working system prototype by extending the Stanford OpenFlow 1.0 Reference Switch and the POX SDN controller. We evaluate our approach through both flow level simulation, and packet level network emulation with Mininet and real media streams. We demonstrate that multicast forwarding using BloomFlow can achieve significant reductions in memory requirements due to network forwarding state (up to a ∼ 79% reduction in realistic WAN topologies under heavy multicast workloads). We find that this forwarding state reduction can be achieved with minimal bandwidth utilization overhead (averaging under ∼ 1%), and that our approach successfully meets time constraints required for deployment in a real-time SDN controller.

Motivated by high quality multimedia and remote collaborative environments, we solve the problem of multigroup multicast routing with a~number of features important for real-world deployment of the interactive media technologies. Based on the ant colony optimization metaheuristic, our algorithm is the first to work with uncertain knowledge of underlying network capabilities and support on-the-fly media transcoding inside the multicast tree. New contributions of this work are described next. We present two extensions of the algorithm, which improve quality of the solution. We introduce an~integrated approach to solution of the problem, which is effective for both original solving from scratch as well as for new dynamic reconfiguration of multicast tree, where minimum perturbation of existing solution is desired. Experiments show that our algorithm is not only successful in maintaining existing communication with low number of unnecessary disruptions, but also capable of keeping the multicast trees efficient.

Multicast and prefix caching are two promising approaches to provide scalable video-on-demand (VoD) services. We contribute to solve the adaptive multicast delivery and the cache allocation problem for VoD services with client caching under asynchronous client requests. We first propose a client caching enabled adaptive multicast delivery scheme, which combines the stream merginglike method with prefix caching and adaptive modulation and coding, to fully exploit the multicast opportunity among asynchronous requests from heterogeneous clients. Next, we derive the bandwidth consumption of the proposed delivery scheme under a given prefix cache allocation and Poisson arrival request. We then optimize the cache allocation to minimize the average bandwidth consumption, and the problem is proved to be convex and solved effectively. Finally, three extreme cases are studied to provide closed-form solutions and more insight on the cache allocation and the delivery scheme for VoD systems.

Cognitive wireless mesh networks (CWMNs) were developed to improve the utilization ratio of licensed spectrum. Since the spectrum opportunities for users vary over time and location, enhancing the spectrum effectiveness is a goal and also a challenge for CWMNs. Multimedia applications have recently generated much interest in CWMNs supporting quality-of-service (QoS) communications. Multicast routing and spectrum allocation is an important challenge in CWMNs. In this paper, we study to design an effective multicast routing algorithm based on diversity rate with respect to load balancing and the number of transmissions for CWMNs. In this paper, a load balancing wireless links weight computing function and computing algorithm based on diversity rate (DRLB) are proposed, and a load balancing channel and rate allocating algorithm based on diversity rate (DR2CS) is proposed. On this basis, a load balancing joint multicast routing, channel and rate allocation algorithm based on diversity rate with QoS constraints for CWMNs (LMR2D) is proposed. Balancing the load of node and channel, and minimizing the number of transmissions of multicast tree are the objectives of LMR2D. Firstly, LMR2D computes the weight of wireless links using DRLB and Dijkstra for constructing the load balancing multicast tree step by step. Secondly, LMR2D uses DR2CS to allocate channel and rate of channel to links which is based on the wireless broadcast advantage. Simulation results show that LMR2D can achieve the expected goal. It can not only balance the load of node and channel, but also need lower number of transmissions for multicast tree.

Reliable and QoS-aware multimedia delivery is one of the most important requirements to satisfy end user needs. IEEE 802.11 networks have become one of the most popular Internet access methods owing to their low-cost and fast connection speed. Multicasting is a transmission technique that can significantly increase network efficiency through the simultaneous delivery of the same multimedia content to multiple multicast group members. IEEE 802.11 describes several multicast protocols targeted to increase the robustness of audio and video delivery. Some researchers have investigated the performance of such multicast protocols in terms of their achievable throughput. However, for a better understanding of the suitability of the protocols for a QoS-aware multimedia transmission, an in-depth analysis of the achievable delay is needed. This study provides a detailed delay analysis and describes analytical models for estimating the average achievable delay of IEEE 802.11 multicast protocols co-existing with legacy stations. The proposed analytical models are compared against simulation results under various conditions and parameter configurations. The simulation results validate the accuracy of the proposed models.

Smart Grids (SGs) are emerging cyber-physical systems, equipped with sophisticated communication and information technologies, for efficient and large-scale power supply and management. SGs demand advanced communication technologies between energy providers and consumers, for enabling a control-feedback loop, by using time-dependent pricing. In this paper, we propose an efficient planning of 5G small cells, with evolved multimedia broadcast and multicast communication, between aggregators (small cells) and SG consumers, for efficient demand-response (DR) programs. After pointing out that optimal multicast scheduling and radio resource management problem is NP-complete, we propose two different solutions, based on dynamic programming (DP) and greedy heuristics, for minimizing the energy cost for DR customers. We also analyze the performance of SG user capacity for 5G single cell multicast and multicast broadcast single frequency network. Extensive OPNET simulation results, over actual energy data and real wireless trace, demonstrate that our proposed 5G small cell planning and multicast solutions are capable of reducing energy production cost by $30\%$ , with up to $35\%$ shift in peak energy load, low latency and packet drop.

Secondary users (SUs) can flexibly access licensed channels to improve the spectrum utilization in cognitive radio networks (CRNs). In mobile cognitive radio ad hoc networks (MCRAHNs) where nodes can move, SUs are intermittently connected because of node mobility, as well as the uncertain channel availability. Providing multicast services in MCRAHNs is urgently needed with the compelling demand on service qualities and varieties, and the proliferation of cognitive technology. The benefits of network coding over multicast in traditional wireless networks or CRNs have been well demonstrated in existing works. However, the existing studies merely address the two crucial issues (i.e., uncertain channel availability and node mobility) together and, thereby, cannot be applied to network coding-based multicast in MCRAHNs. In this paper, we study the problem of network coding-based multicast in MCRAHNs considering both channel uncertainty and node mobility. We utilize discrete-time Markov chains to model the channel availability and node mobility in MCRAHNs, and we then formulate a spectrum-aware network coded multicast problem as an optimization problem, which minimizes the total transmission cost, subject to the timely successful delivery constraint and link transmission constraint. Since the formulated problem is hard to tackle according to mixed integer programing, we further design a distributed spectrum-aware cost-based (SACB) scheme based on the metric of forwarding benefit. With extensive simulations based on both synthetic and realistic traces, we show that, compared with existing schemes, SACB can achieve almost the minimum transmission cost while maintaining high multicast success probability.

Wireless links are inherently lossy due to channel fading or interference. Previously, duplicate packets were transmitted on multiple routes of lossy mobile ad hoc networks (MANETs) to enhance reliability. In this paper, a multicast routing protocol that constructs multiple multicast trees and employs network coding is proposed for lossy MANETs, where each multicast tree can satisfy a predefined percentage of the bandwidth requirement. The proposed protocol can reduce the total bandwidth consumption while providing bandwidth guarantees to a requested flow and ongoing flows. As a consequence of employing network coding, no redundant packet is generated, and no scheduling algorithm for distributing packets among the multicast trees is needed. Simulation results show that the proposed protocol outperforms prior multicast routing protocols in terms of the receiving ratio, the admission ratio, and the total bandwidth consumption.

Distributed mobility management (DMM) is currently being researched and standardized in academia and standardization development organizations for the purpose of overcoming the major issues of existing centralized mobility management. The most recent DMM protocols are being redesigned with regard to the control and data plane separation concept. However, at present, there is no solution for supporting IP multicast listeners in such new DMM environments. In this paper, we review ongoing academic research works, standardization activities and propose an IP multicast mobility design for the DMM environment using the control and data plane concept.

The graphical abstract in the form of Pareto front solutions showing the trade-offs between the objectives is depicted in Fig. 1.Display Omitted Wireless networks have finite battery source, so QoS aware multicast routing must also be energy efficient.There is trade-off between energy consumption and QoS guarantees (i.e. end-to-end delay, delay jitter and packet loss) provided by a wireless network.These requirements are formulated as a multiobjective optimization problem.Ant based multiobjective algorithms are proposed to build an energy efficient multicast tree.Simulation results are compared with NSGA-III. Most of the group communication technologies support real-time multimedia applications such as video conferencing and distributed gaming. These applications require quality-of-service (QoS) aware multicast routing protocol to deliver the same data stream to a predefined group of receivers. Since nodes in wireless networks are severely energy constrained due to finite battery source, hence it is of paramount importance that QoS aware multicast routing protocol be energy efficient. Transmission power control is one of the methods used to save energy. In this method, the nodes dynamically adjust the transmission power so that energy consumption in the tree is minimized. However, reduction in the transmission power increases the number of forwarding nodes in the multicast tree. This negatively impacts the QoS in terms of propagation delay, delay jitter, and packet loss etc. In wireless networks, there is a trade-off between the energy consumption and the QoS guarantees provided by the network. We unify these requirements into a multiobjective framework referred to as Energy Efficient QoS Multicast Routing (E2QoSMR). The goal is to simultaneously optimize the total power consumption and the QoS parameters in the multicast tree. We extend two algorithms based on metaphor of swarm intelligence for finding an energy efficient multicast tree satisfying the QoS guarantees. Extensive simulations have been conducted to validate the correctness and efficiency of the algorithms. The simulation result of the algorithms is compared with the nondominated sorting genetic algorithm, NSGA-III. The experimental results are consolidated by statistical analyses that demonstrate the ability of the algorithms to generate the Pareto optimal solution set.

We propose and investigate a subtree scheme for all-optical multicast routing, modulation level and spectrum allocation (AOM-RMSA) in elastic optical networks. A multicast request is accommodated by several light-trees and each light-tree covers only a part of the destination set. We assume that all nodes are multicast capable and investigate the subtree scheme over the single light-tree scheme for the AOM-RMSA problem under both static and dynamic traffic scenarios. In the static scenario, we formulate an integer linear programming model to obtain the optimal solution. Then, we propose two time-efficient heuristic algorithms that construct subtrees according to the link-sharing ratio between the paths from source to two distinct destinations. The proposed algorithms improve the spectrum utilization by building subtrees that have smaller tree-spanning size and adopt higher level modulation formats. They have also effectively reduced the blocking probability compared to single light-tree schemes.

In this paper, we formulate an integer linear programming (ILP) to perform multicast routing and spectrum assignment (MRSA) in elastic optical networks, which serves jointly a set of multicast requests. In this formulation, all physical layer restrictions including modulation level assignment, maximum number of multicast capable nodes (MCNs), and maximum splitting degree (MSD) of MCNs, are considered. In addition, we modify the proposed joint ILP to serve multicast requests one-by-one, which is referred to as a separate ILP. Furthermore, we present three heuristic algorithms for MRSA, namely distance-based MRSA (DMRSA), congestion-based MRSA (CMRSA), and mixed CMRSA/DMRSA, which are applicable in both static and dynamic operation scenarios. In CMRSA and DMRSA, the link length and the amount of occupied spectrum are considered as the cost function of multicast routing, respectively; and in mixed CMRSA/DMRSA, a combination of normalized link length and normalized occupied spectrum is considered as the cost function. The comparison of ILPs and heuristic algorithms in static operation reveals that the joint ILP, as the benchmark, gives the optimum solution while has the most computational complexity. Furthermore, the separate ILP has lower complexity at the cost of consuming slightly more spectrum. Unless the DMRSA method, which has the worst performance, the gap between the other two heuristic algorithms and the ILPs is negligible. Furthermore, simulation results of dynamic operation scenarios reveal that mixed CMRSA/DMRSA outperforms other two heuristics algorithms in terms of blocking probability.

With the rapid evolution of multimedia and real-time applications like audio/video conferencing, certain quality-of-service (QoS) should be guaranteed for the multicast transmission. For the given delay-constrained multicast request, the goal of delay-constrained survivable multicast routing problem (DCSMRP) is to provide the primary multicast tree and protecting resources so that after recovering from the link (node)-failure, the recovered tree can satisfy the delay constraint. In this article, the DCSMRP with a single node-failure case on wavelength-division multiplexing (WDM) networks is considered. Three node-failure protecting methods, includes node-disjoint trees (NDT), node-encircling p-cycles (NEPCs) and failure-independent path protecting p-cycles (FIPP p-cycles) are used in this article. For each protecting method, an algorithm is designed to solve the studied problem. Simulations are also conducted to evaluate the performance of the proposed algorithms.

This paper deals with the problem of multicast routing in Multi-Radio Multi-Channel Wireless Mesh Networks (MRMC-WMNs) equipped with directional antennas. We jointly consider the wireless broadcast advantage, the directional antenna technology, and the interference-aware path selection metric to improve the network performance. Although using directional antennas reduces the interference, it increases the number of transmissions. The adaptive directional antenna is an effective approach to control this trade-off. In this regard, we propose four cross-layer algorithms named Directional Transmission aware Multicast Tree (DTMT), Directional Interference-aware Multicast Tree (DIMT), Steerable Beam Multicast routing (SBM), and Interference-aware Steerable Beam Multicast routing (ISBM). As an advantage, these algorithms jointly address the problems of multicast tree construction, transmission channel selection, and transmission beam specification. DTMT and DIMT are implemented on three types of graphs called Random Oriented Graph (ROG), Adaptive Oriented Graph (AOG), and Adaptive beam Graph (ABG). AOG and ABG try to find the best sector by steering the directional antennas. Differently, in SBM and ISBM, the beam-width and orientation of each antenna are adaptively characterized during the procedure of the tree construction. Numerical results demonstrate that the proposed algorithms effectively outperform other existing algorithms in terms of the interference and the number of transmissions.

With the growing trend of deploying Software defined networks (SDN) in Internet and data centers, it is necessary to investigate the operation of multicast services in this paradigm shift. We propose an OpenFlowbased virtualized platform to support multiple multicast services simultaneously, each with their own customized multicast algorithms and performance-enhancing strategies for its service requirements. The contributions include: 1) systematic discussions of the technical challenges re-garding to implementing multicast services in SDN, with the proposed architectural components addressing these issues; 2) a virtualized platform enabling user-defined multicast services, independent of current Internet-based protocols; 3) experiments validating the necessity and efficiency of the platform in supporting its design goals and functionalities, with two additional real multicast applications further confirming the feasibility and operability of the proposed prototype.