Multicast Session Research Articles

Impairment-aware multicast session provisioning in metro optical networks

This work investigates the problem of designing, engineering, and evaluating metropolitan area transparent optical networks for the provisioning of multicast sessions. Apart from finding the minimum-cost tree and using metrics on the physical performance of the system, namely the Q-factor, this work investigates different node architecture designs including architectures with active and passive splitters and architectures with different receiver and transmitter designs. Different network engineering approaches are also utilized and are used to ascertain whether a multicast connection should be admitted to the network. “Tree balancing techniques” are used for routing the multicast sessions, aiming at maximizing the multicast connections that can be admitted to the network.

Efficient Multicast Association to Improve the Throughput in IEEE 802.11 WLAN

This paper deals with the problem of optimal association of stations (STAs) to access points (APs) for mulicast services in IEEE 802.11 WLAN. In a multicast session, all the subscribed STAs receive...

Multicast protection and grooming scheme in survivable WDM optical networks

Network survivability is an important factor in the design of WDM optical networks. In dynamic provisioning context, a typical connection request may require bandwidth less than a wavelength channel capacity and it may also require protection from network failure, typically fiber cuts. In this paper, we investigate the multicast traffic protection with grooming in WDM mesh network under single link failure and propose a novel multicast protection algorithm called shared segment protection with grooming (SSPG) that constructs the primary or working light-tree and corresponding link disjoint backup light-tree for each dynamic multicast connection request. In this approach, a backup segment can efficiently share the wavelength channel capacity of its working segments and simultaneously use the common network resources at the backup light-tree. In order to efficiently utilize the network resources (such as wavelength, transceivers, optical splitters and wavelength channels), the sub-wavelength demands are groomed to protect multicast requests against single link failure. The main objective of this work is to minimize the blocking probability of client calls or bandwidth blocking probability of a dynamically changing multicast request of WDM optical networks and efficiently utilize the network resources, respectively. The performances of various algorithms are evaluated based on extensive simulations to study dynamic provisioning of survivable multicast sessions in standard WDM mesh networks. The simulation results reveal that the proposed SSPG produces better performance in terms of blocking probability (in terms of requests), bandwidth blocking probability (in terms of bandwidth capacity), wavelength channel utilization and cost which is associated with the network resources such as transceivers, splitters and wavelengths than existing standard link shared protection with grooming (LSPG) and path-pair shared protection with grooming (PSPG) algorithms.

P-Cycle-based protection of multicast connections in metropolitan area optical networks with physical layer impairments constraints

This paper investigates the problem of protecting multicast sessions in optical networks utilizing a novel cycle-based heuristic algorithm called Q-based p-Cycles Heuristic (QBPCH), that is used for the decomposition of the graph network into a set of p-cycles, while taking into account the physical layer impairments (PLIs) via a Q-budgeting approach. In this technique the length of these cycles is constrained in order to limit the effect of the impairments on the protection paths. The proposed scheme exhibits improved performance in terms of blocking probability, when compared to another proposed heuristic, namely p-Cycles Heuristic (PCH), that aims at decomposing the graph network into a set of p-cycles that maximizes the number of straddling links in the network. Both proposed schemes are also compared to a traditional ring cover heuristic (RC) and to a Hamiltonian cycle (HC) approach and it is shown that QBPCH performs the best in terms of blocking probability when the PLIs are considered.

Joint source-channel rate allocation and client clustering for scalable multistream IPTV.

We design a system framework for streaming scalable internet protocol television (IPTV) content to heterogenous clients. The backbone bandwidth is optimally allocated between source and parity data layers that are delivered to the client population. The assignment of stream layers to clients is done based on their access link data rate and packet loss characteristics, and is part of the optimization. We design three techniques for jointly computing the optimal number of multicast sessions, their respective source and parity rates, and client membership, either exactly or approximatively, at lower complexity. The latter is achieved via an iterative coordinate descent algorithm that only marginally underperforms relative to the exact analytic solution. Through experiments, we study the advantages of our framework over common IPTV systems that deliver the same source and parity streams to every client. We observe substantial gains in video quality in terms of both its average value and standard deviation over the client population. In addition, for energy efficiency, we propose to move the parity data generation part to the edge of the backbone network, where each client connects to its IPTV stream. We analytically study the conditions under which such an approach delivers energy savings relative to the conventional case of source and parity data generation at the IPTV streaming server. Finally, we demonstrate that our system enables more consistent streaming performance, when the clients' access link packet loss distribution is varied, relative to the two baseline methods used in our investigation, and maintains the same performance as an ideal system that serves each client independently.

A load balanced approach of multicast routing and wavelength assignment in WDM networks

Multicast routing and wavelength assignment MRWA deals with the problem of one-to-many communication in a wavelength division multiplexed optical fibre networks. As physical optical networks are equipped with finite number of optical channels in each fibre cable, throughput of the network is treated as a major performance issue. The aim of this work is to maximise throughput in a finite wavelength WDM network. As to establish multicast session a single message may need to split into multiple messages fanning out of a node, the node must contain costly splitters. This work also considers the cost of splitting at the split nodes while establishing a light-tree for a particular multicast session request. Here a load-balancing technique is used to optimise the optical channel requirements to establish a multicast connection. The algorithm proposed here is compared with standard all-shortest path algorithm combined with first-fit wavelength assignment for multicasting by simulation on various network topologies and different network configurations. The simulation result shows that our proposed algorithm performs much better than the standard one.

OFDMA-based multicast with multiple base stations

We consider an orthogonal frequency division multiple access (OFDMA)-based multicast system where multiple base stations transmit a multicast session to a multicast group. The goal is to maximize the multicast rate (i.e. the minimum achievable user rate) subject to a total power constraint. We assume the use of an erasure code (e.g., a Reed--Solomon code) or rateless code (e.g., Luby transform code). This facilitates each user to accumulate rates from their best subchannels, so that the achievable multicast rate is not limited to the worst user. The resource allocation problem involves determining the transmitting base station at each OFDMA subchannel, the number of bits to be transmitted at each subchannel, and the set of nodes to decode the bits at each subchannel. We formulate the problem as a mixed binary integer linear programming and find the optimal solution as a benchmark. We also propose a greedy subchannel and bit allocation algorithm that is close to optimal.

Peer-assisted multimedia delivery using periodic multicast

Multimedia content distribution is one of the most popular services available on the Internet, and several approaches have been developed to satisfy user requirements and reduce server load. IP multicast is one efficient mechanism for distributing content to multiple users with minimal server and network loads. Because its single stream of data is transmitted simultaneously to multiple users, IP multicast is well-suited for real-time broadcasting. However, it is difficult to offer on-demand multimedia services with IP multicast in which users request content without synchronization. In this paper, we propose an on-demand based multimedia delivery system using IP multicast. In our system, the multimedia server starts multicasting content upon receiving the first content request. Subsequent users then join the multicast session at any time during the transmission. The content that subsequent users have missed is provided by the users (peers) that joined earlier, or by server unicasts. To minimize server load, we quantitatively analyzed the optimal multicast starting point. Through simulation, we show that our proposed system outperforms prior related systems based on peer-to-peer delivery and multicasting.

Zone Based Secure Multicast Architecture for Intra-Cluster Communication in MANET

In mobile ad hoc networks (MANETs) in order to enhance efficiency, the multicast MANET is used for a sender node, which sends data packets to a number of nodes in the network through a multicast session. Due to the complicatedness in zone membership management and multicast packet forwarding over a dynamic topology, completion of efficient and scalable multicast with security in MANET becomes a challenge. In order to achieve a secure multicast architecture for MANETS, in this paper, we propose a Zone based Secure Multicast Architecture for Intra-cluster Communication in MANET. Initially, cluster creation is performed. Then, in a broad environment, a zone-based bidirectional tree is constructed and the zone leader is elected using trust value. Trust value is estimated from the Markov trust model. Finally, the secure voting process in the selected zone leader is made by using the elliptic curve discrete algorithm (ECDSA).

On the impact of polarization-dependent gain/loss for optical multicast sessions.

This work focuses on the design and engineering of metropolitan area optical networks for multicast session provisioning. Specifically, the impact of polarization-dependent gain/loss of optical components in coordination with other physical layer impairments is investigated for the first time for several optical multicast algorithms and switch designs. Performance results indicate that the conventional probabilistic handling of PDG/PDL is not practical in this case, requiring a more refined and computationally efficient interaction between physical and control layers.

Minimum Cost Bandwidth Guaranteed Multicast Routing in Multi-channel Multi-radio Wireless Mesh Networks

Multicast communication is an important service in wireless mesh networks (WMNs). It covers a broad range of applications, including data distribution, video conferencing, and distance learning. In this paper, we discuss the issue of bandwidth guaranteed multicast routing in multi-channel multi-radio WMNs. The problem of our concern is to construct a tree per multicast session such that the cost of the system, which is defined as the amount of total consumed bandwidth, is minimized. In order to solve the problem efficiently, we design Bandwidth Guaranteed Minimum Cost Tree construction (BGMCT) algorithm. Our algorithm yields cost-effective solutions as it exploits the wireless broadcast advantage (WBA) property of the wireless medium. In the proposed algorithm, we have developed two strategies for constructing minimum cost trees. Firstly, the number of the relay nodes in each tree is minimized. Secondly, the amount of overlapping between the shortest paths which connect different destinations of each session to its source node, is taken into account. The simulation results demonstrate that our algorithm outperforms existing solutions. Moreover, BGMCT provides near to optimal outcomes in a reasonable time.

MULTICAST ROUTING WITH QUALITY OF SERVICE CONSTRAINTS IN THE AD HOC WIRELESS NETWORKS

The recent multimedia applications and services are very demanding in terms of Quality of Service (QoS). This creates new challenges in ensuring QoS when delivering those services over wireless networks. Motivated by the need of supporting high quality multicast applications in wireless ad hoc networks, we propose a network topology that can minimize the power when connecting the source node to the destination nodes in multicast sessions with the respect of the QoS provisions. We formulated the problem as integer linear programming problem with a set of energy and QoS constraints. We minimize the total power of energy used by nodes while satisfying QoS constraints (Bandwidth and maximum delay) that are crucial to wireless ad hoc network performance.

Splitting minimization: a novel approach for multicasting in WDM mesh networks

Multicast routing and wavelength assignment is an important problem in optical fiber networks where dedicated connections are required to be established between a source and multiple number of destinations. To establish such a multicast session, some of the nodes in the network should be capable of splitting an incoming message, in the form of light signal, into multiple outgoing signals. These nodes, also known as multicast capable (MC) nodes, are very costly due to the requirement of signal amplification and difficulty in fabrication. In this paper, we study routing and wavelength assignment problem for multicast communication in WDM mesh network to minimize splitting requirement as well as the delay in communication, which is a major QoS parameter in one-to-many data communication. As the objectives show an opposing behavior, a tread-off solution is often required. Here we have proposed a heuristic based algorithm, which gives an efficient trade-off solution for the problem. On comparison under different network topologies, the proposed algorithm is found to be more efficient than the existing algorithms.

Cooperation Versus Multiplexing: Multicast Scheduling Algorithms for OFDMA Relay Networks

With the next-generation cellular networks making a transition toward smaller cells, two-hop orthogonal frequency-division multiple access (OFDMA) relay networks have become a dominant, mandatory component in the 4G standards (WiMAX 802.16j, 3GPP LTE-Adv). While unicast flows have received reasonable attention in two-hop OFDMA relay networks, not much light has been shed on the design of efficient scheduling algorithms for multicast flows. Given the growing importance of multimedia broadcast and multicast services (MBMS) in 4G networks, the latter forms the focus of this paper. We show that while relay cooperation is critical for improving multicast performance, it must be carefully balanced with the ability to multiplex multicast sessions and hence maximize aggregate multicast flow. To this end, we highlight strategies that carefully group relays for cooperation to achieve this balance. We then solve the multicast scheduling problem under two OFDMA subchannelization models. We establish the NP-hardness of the scheduling problem even for the simpler model and provide efficient algorithms with approximation guarantees under both models. Evaluation of the proposed solutions reveals the efficiency of the scheduling algorithms as well as the significant benefits obtained from the multicasting strategy.

SLIM - Simple Lightweight and Intuitive Multicast Protocol for MANETs

Real time video multicast has always been a topic of active research for almost all types of computer networks. With the shift of focus towards Mobile Ad-hoc Networks (MANETs), several approaches have been suggested for the creation and maintenance of multicast trees in the dynamic and unpredictable environment of MANETs. This paper presents a simple and novel approach for Multicasting in MANETs that is particularly suited for multicasting live video/audio streams. The approach is lightweight, scalable and is general that it can be made to work with any underlying unicast routing protocol such as AODV, DSDV, and DSR among others. The paper describes the protocol in details including how a node will join or leave a multicast session; how the multicast tree is maintained and how it copes with the mobility of nodes.

Information Networks With In-Block Memory

A class of channels is introduced for which there is memory inside blocks of a specified length and no memory across the blocks. The multi-user model is called an information network with in-block memory (NiBM). It is shown that block-fading channels, channels with state known causally at the encoder, and relay networks with delays are NiBMs. A cut-set bound is developed for NiBMs that unifies, strengthens, and generalizes existing cut bounds for discrete memoryless networks. The bound gives new finite-letter capacity expressions for several classes of networks including point-to-point channels, and certain multiaccess, broadcast, and relay channels. Cardinality bounds on the random coding alphabets are developed that improve on existing bounds for channels with action-dependent state available causally at the encoder and for relays without delay. Finally, quantize-forward network coding is shown to achieve rates within an additive gap of the new cut-set bound for linear, additive, Gaussian noise channels, symmetric power constraints, and a multicast session.

Bounds on end-to-end statistical delay and jitter in multiple multicast coded packet networks

Network coding is a paradigm in data transport that allows a network node to code information flows before forwarding them. While it has been theoretically proven that network coding saves bandwidth and increases throughput of multicast communication, it does not directly consider the quality of service (QoS) requirements of multicast routing. In this paper, we study the problem of establishing minimum-cost, multiple multicast sessions over coded packet networks to meet the statistical QoS target considering bounded end-to-end statistical delay and jitter from source to each destination. For this purpose, we first propose a path-based formulation for the problem and prove that this problem is NP-hard. Then, in order to obtain an exact solution, we present an effective and efficient decomposition approach in which the problem is decomposed into master problem and subproblems, and the solution is built up successively by feasible path generation. Computational results on random networks show that the proposed method provides an efficient way for solving the problem, even for relatively large networks.

Bounds on the Benefit of Network Coding for Wireless Multicast and Unicast

In this paper, we explore fundamental limitations of the benefit of network coding in multihop wireless networks. We study two well-accepted scenarios in the field: single multicast session and multiple unicast sessions. We assume arbitrary but fixed topology and traffic patterns for the wireless network. We prove that the gain of network coding in terms of throughput and energy saving of a single multicast session is at most a constant factor. Also, we present a lower bound on the average number of transmissions of multiple unicast sessions under any arbitrary network coding. We identify scenarios under which network coding provides no gain at all, in the sense that there exists a simple flow scheme that achieves the same performance. Moreover, we prove that the gain of network coding in terms of the maximum transport capacity is bounded by a constant factor of at most $(\pi)$ in any arbitrary wireless network under all traditional Gaussian channel models. As a corollary, we find that the gain of network coding on the throughput of large homogeneous wireless networks is asymptotically bounded by a constant. Furthermore, we establish theorems which relate a network coding scheme to a simple routing scheme for multiple unicast sessions. The theorems can be used as criteria for evaluating the potential gain of network coding in a given wired or wireless network. Based on these criteria, we find more scenarios where network coding has no gain on throughput or energy saving.

A fixed point model for rate control and routing in cloud data center networks

ABSTRACTThis paper addresses the issues of rate control and routing for cloud data center networks. Based on the theory of the supply–demand equilibrium, we propose a fixed point model for formulating cloud network equilibrium problems in which the equilibrium conditions are given by nonlinear equations. We show that the network equilibrium point is the optimal solution of a nonlinear programming problem by utilizing the tools of the variational inequality and convex optimization. The augmented Lagrangian multiplier algorithm is used to solve the nonlinear programming problem for computing the network equilibrium point. Further consideration is given to the equilibrium problems of a cloud network with multirate multicast sessions. We evaluate our approach on some random networks with unicast and multicast sessions, and the results show the effectiveness of our approach in finding the optimal equilibrium rates. We further evaluate the performance of our approach through cloud data center network simulation under various parameter settings, and the results show that the performance of our algorithm can be tuned and improved by choosing appropriate parameter values. Copyright © 2013 John Wiley & Sons, Ltd.

Optimal Self-Adaptive QoS Resource Management in Interference-Affected Multicast Wireless Networks

In this paper, we focus on the quality-of-service (QoS)-constrained jointly optimal congestion control, network coding, and adaptive distributed power control for connectionless wireless networks affected by multiple access interference (MAI). The goal is to manage the available network resources, so as to support multiple multicast sessions with QoS requirements when intrasession network coding (NC) is allowed. To cope with the nonconvex nature of the resulting cross-layer optimization problem, we propose a two-level decomposition that provides the means to attain the optimal solution through suitable relaxed convex versions of its comprising subproblems. Sufficient conditions for the equivalence of the primary nonconvex problem and its related convex version are derived, occurrence of such conditions investigated, and performance with respect to conventional routing-based layered solutions analyzed. Moreover, we develop a distributed algorithm to compute the actual solution of the resource allocation problem that quickly adapts to network time-evolutions. Performance of this algorithm and its adaptivity are evaluated in the presence of varying network/fading conditions and noisy measurements.