Adaptive group multicast with time-driven priority

This paper shows how to provide an adaptive real-time group multicast (many-to-many) communication service. Adaptive means that the number of nodes that transmit to the multicast group is continuously changing. In order to meet deterministic quality-of-service (QoS) requirements of a real-time group multicast, some communication resources are reserved. We show (1) how bandwidth is reserved for each multicast group and (2) how an active source can dynamically share the bandwidth allocated to this multicast group with other active group members. Quality-of-service support for a real-time multicast group is based on time-driven priority. In this scheme the time is divided into time frames of fixed duration, and all the time frames are aligned by using a common global time reference, which can be obtained from the Global Positioning System. Bandwidth is allocated to a multicast group as a whole, rather than individually to each user. The allocation is done by reserving time intervals within time frames in a periodic fashion. This type of allocation raises two problems that are studied in this paper: (1) scheduling: how time intervals are reserved to each multicast group and (2) adaptive sharing: how the active (transmitting) participants can dynamically share the time intervals that have been reserved for their multicast group. The proposed approach is based on the embedding of multiple virtual rings, one for each multicast group. By using the virtual rings, it is simple to route messages to all the participants while minimizing the bound on the buffer sizes and queueing delays. The final part of this paper introduces a scalable growth of the multicast group by adding multiple subtrees to the virtual ring     

Improved Shuffled Frog-Leaping Algorithm Based QoS Constrained Multicast Routing for Vanets

Prompt and reliable communication between vehicular nodes are essential as its limited coverage and dynamic mobility rate introduces frequent change of network topology. The key feature of vehicular communication that establishes direct connectivity or Road Side Unit-based data transfer among vehicular nodes is responsible for sharing emergency information during critical situations. Multicast routing data dissemination among vehicular nodes is considered to be the potential method of parallel data transfer as they facilitate the option of determining an optimal multicast tree from feasible number of multicast trees established between the source and destinations. This estimation of optimal multicast tree using meta-heuristic techniques is confirmed to improve the throughput and reliability of the network when QoS-based constraints are imposed during multicast routing. An Improved Shuffled Frog-Leaping Algorithm-Based QoS Constrained Multicast Routing (ISFLABMR) is proposed for estimating an optimal multicast tree that confirms effective multi-constrained applied multicast routing between vehicular nodes. ISFLABMR minimizes the cost of transmission to 22% by reducing the number of multicast clusters formed during multicasting through the utilization of local and global-based optimizations. The simulation results of ISFLABMR proveits predominant reduction rate of 24% and 21% in average packet latency and energy consumptions incurred under multicast routing.     

Multipoint communication: a survey of protocols, functions, andmechanisms

Group communication supports information transfer between a set of participants. It is becoming more and more relevant in distributed environments. For distributed or replicated data, it provides efficient communication without overloading the network. For some types of multimedia applications, it is the only way to control data transmission to group members. This paper surveys protocol functions and mechanisms for data transmission within a group, from multicast routing problems up to end-to-end multipoint transmission control. We provide a bibliography which is organized by topic     

An evaluation of flow control in group communication

Group communication services have been successfully used to construct applications with high availability, dependability, and real-time responsiveness requirements. Flow control techniques enable group members to manage their local buffers, which they use to temporarily store multicast updates. Despite buffer overflow being one of the main causes of process failures, flow control has not been studied much in the literature. We study different flow control techniques used in some of the group communication services and present two generic flow control techniques: a conservative and an optimistic technique. All existing flow control techniques for group communication can be classified as either conservative or optimistic. We then present discrete event simulation results that compare the effect of these two generic flow control techniques on the performance of two, different atomic multicast protocols, a positive acknowledgment protocol and a negative acknowledgment protocol, under several different operating conditions. Based on the study of differed existing flow control techniques for group communication and the results obtained from the simulation experiment, we provide some design guidelines for the design and implementation of a suitable flow control technique for a given group communication service     

Security in enterprise networking: A quick tour

Enterprise networks are complex environments that involve the interconnection of a wide variety of computer systems such as portable PCs and personal digital assistants (PDAs), desktop PCs and workstations, servers, and mainframes, with a wide variety of communication channels such as dial-in and mobile access via modems, local area networks (LANs), wide area networks (WANs), and the Internet. The authors provide an overview of the major areas in the security of enterprise networks to show the variety of issues and techniques developed to address them. Our focus is on the ideas behind these techniques, which can be combined in many ways to create solutions that apply to different situations. The following areas are covered: confidentiality, preventing the disclosure of transmitted data to unauthorized parties; integrity, detecting modification, insertion, deletion, or replay of transmitted data; data-origin authentication, demonstrating that the origin of transmitted data is as claimed; nonrepudiation, preventing either the sender or receiver in a communication from denying their participation; user authentication, demonstrating that the identity of a user or system is as claimed; and access control, guarding against unauthorized use of resources, including the use of resources in an improper manner. We also look at some of the considerations that come into play in designing security solutions for the enterprise networking environment     

Multicasting to multiple groups over broadcast channels

Multicasting is a communication mode in which a given source communicates with a subset of the entire network user population. Previous work in this area concentrated on the multicast problem of a single source that always communicates with the same destination group. In this paper we investigate a more natural case of multicast communication where a single source communicates with several different destination groups. Specially, we focus on the design and analysis of multicast data link protocols for this environment. Straightforward implementations of such protocols are inappropriate in the case of a large destination population, as a source will have to store a large amount of state information even if it maintains only a single variable per destination. In most typical applications, though. The total destination population is large, the number of destinations that any given source is in conversation with, is typically small. We propose a framework for adapting protocols so that memory requirement does not grow with the total destination population but depends upon the number of destinations actually in communication with the source. The savings in memory are achieved by slightly increasing the amount of communication. We address the performance of such a protocol in an environment of a broadcast channel. We analyze several strategies and control techniques and demonstrate the tradeoff between throughput and the amount of memory     

On properties of multicast routing trees

In the last several years we witnessed the proliferation of multimedia applications on the Internet. One of the unavoidable techniques to support this type of communication is multicasting. However, even a decade after its initial proposal, multicast is still not widely deployed. One of the reasons is the lack of a solid business model. If the gain and the cost of multicast could be predicted, network operators might be encouraged to deploy multicast on a larger scale. In this paper we propose analytical expressions that could be used to estimate the gain of network‐layer multicast. We show that the theoretical model matches extensive simulation and Internet measurement results remarkably well. Furthermore, we examine the reliability of traceroute data and of traceroutes‐based conclusions. We investigate the node degree distributions in the Internet maps obtained from CAIDA and RIPE and we show the divergency of our results with those obtained by other researchers. We further focus on the analysis of multicast trees based on traceroute data. Only few results have been available on the node degree distribution of multicast routing trees which provided contradictory conclusions. Our results seem to indicate that the node degrees follow power laws only for a large number of multicast users. Copyright © 2005 John Wiley & Sons, Ltd.     

Atomic multicast protocol for intrusion-tolerance based on trusted timely computing base

Distributed architecture is often adopted for the intrusion-tolerance system currently. However, this distributed intrusion-tolerance system has a consensus problem. To solve this problem, this article explores a distributed intrusion-tolerance system of hybrid time model based on trusted timely computing base (TTCB) and implement an atomic multicast protocol using TTCB services. The TTCB is a trust secure real-time component inside the server, with a well defined interface and separated from the operation system. It is in the synchronous communication environment, while the application layer in the server works asynchronously. By the atomic multicast protocol, it can be achieved that when the servers are over twice the number of faulty servers, the consensus can be satisfied. The performance evaluations show that the proposed protocol can yield larger good throughput with a lower unavailability.     

On achieving maximum multicast throughput in undirected networks

The transmission of information within a data network is constrained by the network topology and link capacities. In this paper, we study the fundamental upper bound of information dissemination rates with these constraints in undirected networks, given the unique replicable and encodable properties of information flows. Based on recent advances in network coding and classical modeling techniques in flow networks, we provide a natural linear programming formulation of the maximum multicast rate problem. By applying Lagrangian relaxation on the primal and the dual linear programs (LPs), respectively, we derive a) a necessary and sufficient condition characterizing multicast rate feasibility, and b) an efficient and distributed subgradient algorithm for computing the maximum multicast rate. We also extend our discussions to multiple communication sessions, as well as to overlay and ad hoc network models. Both our theoretical and simulation results conclude that, network coding may not be instrumental to achieve better maximum multicast rates in most cases; rather, it facilitates the design of significantly more efficient algorithms to achieve such optimality.     

Scalable reliable multicast using multiple multicast channels

We examine an approach for providing reliable, scalable multicast communication, involving the use of multiple multicast channels for reducing receiver processing costs and reducing network bandwidth consumption in a multicast session. In this approach a single multicast channel is used for the original transmission of packets. Retransmissions of packets are done on separate multicast channels, which receivers dynamically join and leave. We first show that protocols using an infinite number of multicast channels incur much less processing overhead at the receivers compared to protocols that use only a single multicast channel. This is due to the fact that receivers do not receive retransmissions of packets they have already received correctly. Next, we derive the number of unwanted redundant packets at a receiver due to using only a finite number of multicast channels, for a specific negative acknowledgment (NAK)-based protocol. We then explore the minimum number of multicast channels required to keep the cost of processing unwanted packets to a sufficiently low value. For an application consisting of a single sender transmitting reliably to many receivers we find that only a small number of multicast channels are required for a wide range of system parameters. In the case of an application where all participants simultaneously act as both senders and receivers a moderate number of multicast channels is needed. Finally, we present two mechanisms for implementing multiple multicast channels, one using multiple IP multicast groups and the other using additional router support for selective packet forwarding. We discuss the impact of both mechanisms on performance in terms of end-host and network resources     

Scalable adaptive hierarchical clustering

We propose a new application-level clustering algorithm capable of building an overlay spanning tree among participants of large multicast sessions, without any specific help from the network routers. The algorithm and associated protocol are shown to exhibit scalable properties     

A survey of proposals for an alternative group communication service

As expectations for the Internet to support multimedia applications grow, new services need to be deployed. One of them is the group communication service for one-to-many or many-to-many data delivery. After more than a decade of important research and development efforts, the deployment of multicast routing in the Internet is far behind expectations. Therefore, a first motivation for an alternative group communication service is to bypass the lack of native IP multicast routing. Although less efficient and scalable than native multicast routing, such alternative services are generally suitable for the purpose. A second possible motivation is to go beyond the limitations of classic multicast routing for very specific working environments. We identify, classify, and discuss some of these alternative approaches.     

A ring-based multicast routing topology with QoS support in wireless mesh networks

Wireless mesh networking (WMN) is an emerging technology for future broadband wireless access. The proliferation of the mobile computing devices that are equipped with cameras and ad hoc communication mode creates the possibility of exchanging real-time data between mobile users in wireless mesh networks. In this paper, we argue for a ring-based multicast routing topology with support from infrastructure nodes for group communications in WMNs. We study the performance of multicast communication over a ring routing topology when 802.11 with RTS/CTS scheme is used at the MAC layer to enable reliable multicast services in WMNs. We propose an algorithm to enhance the IP multicast routing on the ring topology. We show that when mesh routers on a ring topology support group communications by employing our proposed algorithms, a significant performance enhancement is realized. We analytically compute the end-to-end delay on a ring multicast routing topology. Our results show that the end-to-end delay is reduced about 33 %, and the capacity of multicast network (i.e., maximum group size that the ring can serve with QoS guarantees) is increased about 50 % as compared to conventional schemes. We also use our analytical results to develop heuristic algorithms for constructing an efficient ring-based multicast routing topology with QoS guarantees. The proposed algorithms take into account all possible traffic interference when constructing the multicast ring topology. Thus, the constructed ring topology provides QoS guarantees for the multicast traffic and minimizes the cost of group communications in WMNs.     

Scaling Group Communication Services with Self-adaptive and Utility-driven Message Routing

Group communication services typically generate large multicast data streams. Delivering such massive data streams to the end system nodes at the edge of the Internet has been a challenging problem in terms of high stress on the network links and high demand on network resources and routing node capacities. Most of existing research has been dedicated on geo-distance based routing with various optimizations to alleviate the performance impact on geo-distance based routing due to unpredictable network dynamics. Most representative techniques are targeted at reducing the delivery path length or optimizing routing path by utilizing network locality. In this paper, we identify the inefficiency of geo-distance based routing protocols in many existing multicast overlay networks in terms of both resource utilization and group communication efficiency. To address this issue, we develop a utility-based routing scheme (UDR) that can provide efficient group communication services in a decentralized geographical overlay network. Our approach makes three unique contributions. First, we introduce a utility function to refine the geo-distance based routing in such a way that the routing path selection can carefully incorporate both geo-distance based metric and the network latency. Second, we enhance our utility driven routing scheme with self-adaptive capability by considering the nodes?? state and network density. Thus, nodes in the multicast network can dynamically accommodate the changes of network conditions based solely on their local knowledge about the network. Third, we devise a suite of optimization techniques to minimize the maintenance cost and computational complexity of our self-adaptive and utility-drive routing scheme. We evaluate our approach through extensive experiments based on a realistic network topology model and show that the UDR method is highly scalable and it effectively enhances the multicast delivery efficiency for large scale group communication services compared to existing geo-distance based routing protocols.     

Efficient solutions to multicast routing in communication networks

An important problem in both wireless and wired communication networks is to be able to efficiently multicst information to a group of network sites. Multicasting reduces the transmission overhead of both wireless and wired networks and the time it takes for all the nodes in the subset to receive the information. Since transmission bandwidth is a scarce commodity especially in wireless networks, efficient and near minimum-cost multicast algorithms are particularly useful in the wireless context. In this paper, we discuss methods of establishing efficient and near minimum-cost multicast routing in communication networks. In particular, we discuss an efficient implementation of a widely used multicast routing method which can construct a multicast tree with a cost no greater than twice the cost of an optimal tree. We also present two efficient multicast tree constructions for a general version of the multicast routing problem in which a network consists of different classes of nodes, where each class can have one or more nodes of the same characteristic which is different from the characteristics of nodes from other classes. Because of their efficient running times, these multicast routing methods are particularly useful in the mobile communication environments where topology changes will imply recomputation of the multicast trees. Furthermore, the proposed efficient and near minimum-cost multicast routing methods are particularly suited to the wireless communication environments, where transmission bandwidth is more scarce than wired communication environments.Partially supported by NSF/LaSER under grant number EHR-9108765, by LEQSF grant number 94-RD-A-39, by NASA under grant number NAG 5-2842.     

A taxonomy of multicast data origin authentication: Issues and solutions

Multicasting is an efficient communication mechanism for group-oriented applications such as videoconferencing, broadcasting stock quotes, interactive group games, and video on demand. The lack of security obstructs a large deployment of this efficient communication model. This limitation motivated a host of research works that have addressed the many issues relating to securing the multicast, such as confidentiality, authentication, non-repudiation, integrity, and access control. Many applications, such as broadcasting stock quotes and video-conferencing, require data origin authentication of the received traffic. Hence, data origin authentication is an important component in the multicast security architecture. Multicast data origin authentication must take into consideration the scalability and the efficiency of the underlying cryptographic schemes and mechanisms, because multicast groups can be very large and the exchanged data is likely to be heavy in volume (streaming). Besides, multicast data origin authentication must be robust enough against packet loss because most multicast multimedia applications do not use reliable packet delivery. Therefore, multicast data origin authentication is subject to many concurrent and competitive challenges, when considering these miscellaneous application-level requirements and features. In this article we review and classify recent works dealing with the data origin authentication problem in group communication, and we discuss and compare them with respect to some relevant performance criteria.     

Network coded multicast for multi-hop D2D communication systems

ABSTRACT

In this paper, we consider the wireless communication systems where multi-hop Device-to-Device (D2D) networks can coexist with the conventional cellular networks by sharing the downlink resource of cellular users (CUs). A multicast data flow is distributed over the multi-hop D2D networks where network coding (NC) can be employed at the intermediate nodes. To maximize the utility of the multicast flow, we formulate a joint optimization problem for the systems while guaranteeing the quality-of-service (QoS) for regular CUs. We propose a subgradient algorithm to solve the optimization problem by decomposing it into three sub-problems: multicast rate control, NC subgraph selection, and downlink resource reusing. In particular, we develop a greedy algorithm to deal with the downlink resource reusing sub-problem for it is NP hard. Numerical and simulation results prove the superior performance of the proposed techniques compared with the conventional routing scheme.     

基于VPE的可信虚拟域构建机制

针对现有可信虚拟域构建方式无法满足云计算灵活配置等特性的问题,结合云计算企业内部敏感数据的防泄漏需求,提出了基于VPE的可信虚拟域构建方法TVD-VPE。TVD-VPE利用分离式设备驱动模型构建虚拟以太网VPE,通过后端驱动截获数据分组,并进行边界安全策略检查,最后对满足策略的数据帧进行加密。同时,还设计了可信虚拟域加入/退出协议确保用户虚拟机安全加入/退出,为边界安全策略的部署设计了面向可信虚拟域的管理协议,同时为高特权用户的跨域访问设计了跨域访问协议。最后,实现了原型系统并进行了功能测试及性能测试,测试结果证明本系统可以有效地防止非法访问,同时系统对Xen的网络性能的影响几乎可以忽略。     

A survey of data multicast techniques, architectures, andalgorithms

This article presents a survey of architectures, techniques, and algorithms for multicasting data in communication switching networks. We start with a broadcast architecture using a separate copy network and a routing network. A few versions of this idea using Delta and Benes networks exist. Another multicast architecture is a recycling network where internal nodes act as relay points, accept packets from the switching fabric, and recycle them back into the fabric after relabeling the packets. Next, we give an overview of a system that uses the Boolean splitting multicast algorithm. In this system a nonblocking self routing broadcast banyan copy network has been proposed. The network consists of several components including a running adder network to generate running sums of copy numbers specified in the headers of input packets. We then describe a multicasting technique presented for a different class of switching networks called deflection-routing networks. Finally, the idea of extending a nonblocking network to a three-dimensional structure consisting of multiple parallel planes is also presented. At the end of this article, we compare the efficiencies of the presented multicast architectures     

A source authentication scheme based on message recovery digital signature for multicast

The source authentication is an important issue for the multicast applications because it can let the receiver know whether the multicast message is sent from a legal source or not. However, the previously related schemes did not provide the confidentiality for data packets. In addition, the communication costs of these schemes are still high for real‐time applications in the multicast environments. To solve the aforementioned problems, we propose a new source authentication scheme based on message recovery signature for multicast in this paper. In the proposed scheme, the encrypted data can be embedded in the digital signature, so the communication loads can be greatly reduced. In addition, the digital signature contains the encrypted data, and thus the confidentiality of data packets can be well protected. According to the aforementioned advantages, the proposed scheme is securer and more efficient than the related works for the real‐time applications. Copyright © 2013 John Wiley & Sons, Ltd.