Explicit Multicasting for Mobile Ad Hoc Networks

In this paper we propose an explicit multicast routing protocol for mobile ad hoc networks (MANETs). Explicit multicasting differs from common approaches by listing destination addresses in data packet headers. Using the explicit destination information, the multicast routing protocol can avoid the overhead of employing its own route construction and maintenance mechanisms by taking advantage of unicast routing table. Our protocol – termed Differential Destination Multicast (DDM) – is an explicit multicast routing protocol specifically designed for MANET environment. Unlike other MANET multicasting protocols, instead of distributing membership control throughout the network, DDM concentrates this authority at the data sources (i.e. senders) thereby giving sources knowledge of group membership. In addition, differentially-encoded, variable-length destination headers are inserted in data packets which are used in combination with unicast routing tables to forward multicast packets towards multicast receivers. Instead of requiring that multicast forwarding state to be stored in all participating nodes, this approach also provides the option of stateless multicasting. Each node independently has the choice of caching forwarding state or having its upstream neighbor to insert this state into self-routed data packets, or some combination thereof. The protocol is best suited for use with small multicast groups operating in dynamic MANET environment.     

MINIMIZING INTERMEDIATE MULTICAST ROUTING FOR DYNAMIC MULTI-HOP AD HOC NETWORKS

A Minimizing Intermediate Multicast Routing protocol （MIMR） is proposed for dynamic multi-hop ad hoc networks. In MIMR, multicast sessions are created and released only by source nodes. In each multicast session process, the source node keeps a list of intermediate nodes and destinations, which is encapsulated into the packet header when the source node sends a multicast packet. Nodes receiving multicast packets decide to accept or forward the packet according to the list. Depending on topology matrix maintained by unicast routing, the shortest virtual hierarchy routing tree is constructed by improved Dijkstra algorithm. MIMR can achieve the minimum number of intermediate nodes, which are computed through the tree. No control packet is transmitted in the process of multicast session. Load of the network is largely decreased. Experimental result shows that MIMR is flexible and robust for dynamic ad hoc networks.     

Overlay,Borůvka‐based,Ad‐hoc multicast Protocol: description and performance analysis

This paper presents a novel Mobile Ad‐hoc NETworks (MANET) multicast protocol, named Overlay Borůvka‐based Ad‐hoc Multicast Protocol (OBAMP), and evaluates its performance. OBAMP is an overlay protocol: it runs only in the end‐systems belonging to the multicast group. OBAMP has three distinctive features, which give to the protocol a good performance in terms of distribution efficiency: (i) its distribution tree closely resembles the minimum spanning tree; (ii) it exploits broadcast communications; (iii) its design limits not only overlay signaling but also network‐layer signaling. In addition, OBAMP can cope with node failures in a very short time. As a consequence, OBAMP has a low latency and a high delivery ratio, even when the group size increases. To prove these statements, we analyze the performance of OBAMP with ns‐2 and compare it with three state‐of‐the‐art protocols, namely ODMRP (a network‐layer protocol), ALMA, and AMRoute (two overlay protocols). The overlay protocols are assumed to use AODV as underlying routing protocol. Also, we stress that we have implemented OBAMP, in Java, and we have tested it on the field, to prove its feasibility; to allow fellow researchers to reproduce and test our work we published all simulation and implementation codes. Copyright © 2007 John Wiley & Sons, Ltd.     

A protocol for scalable loop-free multicast routing

In network multimedia applications such as multiparty teleconferencing, users often need to send the same information to several (but not necessarily all) other users. To manage such one-to-many or many-to-many communication efficiently in wide-area internetworks, it is imperative to support and perform multicast routing. Multicast routing sends a single copy of a message from a source to multiple receivers over a communication link that is shared by the paths to the receivers. Loop-freedom is an especially important consideration in multicasting because applications using multicasting tend to be multimedia and bandwidth intensive, and loops in multicast routing duplicate looping packets. We present and verify a new multicast routing protocol, called multicast Internet protocol (MIP), which offers a simple and flexible approach to constructing both group-shared and shortest-paths multicast trees. MIP can be sender-initiated or receiver-initiated or both; therefore, it can be tailored to the particular nature of an application's group dynamics and size. MIP is independent of the underlying unicast routing algorithms used. MIP is robust and adapts under dynamic network conditions (topology or link cost changes) to maintain loop-free multicast routing. Under stable network conditions, MIP has no maintenance or control message overhead. We prove that MIP is loop-free at every instant, and that it is deadlock-free and obtains multicast routing trees within a finite time after the occurrence of an arbitrary sequence of topology or unicast changes     

The core-assisted mesh protocol

The core-assisted mesh protocol (CAMP) is introduced for multicast routing in ad hoc networks. CAMP generalizes the notion of core-based trees introduced for internet multicasting into multicast meshes that have much richer connectivity than trees. A shared multicast mesh is defined for each multicast group; the main goal of using such meshes is to maintain the connectivity of multicast groups even while network routers move frequently, CAMP consists of the maintenance of multicast meshes and loop-free packet forwarding over such meshes. Within the multicast mesh of a group, packets from any source in the group are forwarded along the reverse shortest path to the source, just as in traditional multicast protocols based on source-based trees. CAMP guarantees that within a finite time, every receiver of a multicast group has a reverse shortest path to each source of the multicast group. Multicast packets for a group are forwarded along the shortest paths front sources to receivers defined within the group's mesh. CAMP uses cores only to limit the traffic needed for a router to join a multicast group; the failure of cores does not stop packet forwarding or the process of maintaining the multicast meshes     

移动自组织网络中基于树结构的优化组播路由算法(英)

Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.     

Congestion control for fair resource allocation in networks with multicast flows

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

OMAC: A new access control architecture for overlay multicast communications

Multicast communications concern the transfer of data among multiple users. Multicast communications can be provided at the network layer—an example is IP multicast—or at the application layer, also called overlay multicast. An important issue in multicast communications is to control how different users—senders, receivers, and delivery nodes—access the transmitted data as well as the network resources. Many researchers have proposed solutions addressing access control in IP multicast. However, little attention has been paid to overlay multicast. In this paper, we investigate the access control issues in overlay multicast and present OMAC: a new solution to address these issues. OMAC provides access control for senders, receivers, and delivery nodes in overlay multicast. The proposed architecture, which is based on symmetric key cryptosystem, centralizes the authentication process in one server whereas it distributes the authorization process among the delivery nodes. Moreover, delivery nodes are utilized as a buffer zone between end systems and the authentication server, making it less exposed to malicious end systems. To evaluate our work, we have used simulation to compare the performance of OMAC against previous solutions. Results of the simulation show that OMAC outperforms previous multicast access control schemes. Copyright © 2010 John Wiley & Sons, Ltd.     

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

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

一种节点自分布最优Ad Hoc多播树及其应用

为无线单播模式设计的RTS/CTS信道握手机制不适用于多播模式,导致Ad hoc多播树节点易与隐藏终端发生冲突.通过提出m阶冲突域、节点在冲突域中的分布指标,结合无线网多播数据通信机制分析树节点所在m阶冲突域的冲突概率,进而得到节点自分布最优树的概念,并将它融入多播树的适应函数的设计中,淘汰不良树,优化树节点在m阶冲突域中的分布,在网络层形成一种预防机制,可降低隐藏终端冲突概率;应用于MAODV协议中,提高了MAODV的端到端数据分组平均投递率,这也能够为基于网的和混合式的其他类型MANETs多播路由协议的路由节点分布优化提供有价值的参考.     

The PIM architecture for wide-area multicast routing

The purpose of multicast routing is to reduce the communication costs for applications that send the same data to multiple recipients. Existing multicast routing mechanisms were intended for use within regions where a group is widely represented or bandwidth is universally plentiful. When group members, and senders to those group members, are distributed sparsely across a wide area, these schemes are not efficient; data packets or membership report information are occasionally sent over many links that do not lead to receivers or senders, respectively. We have developed a multicast routing architecture that efficiently establishes distribution trees across wide area internets, where many groups will be sparsely represented. Efficiency is measured in terms of the router state, control message processing, and data packet processing, required across the entire network in order to deliver data packets to the members of the group. Our protocol independent multicast (PIM) architecture: (a) maintains the traditional IP multicast service model of receiver-initiated membership, (b) supports both shared and source-specific (shortest-path) distribution trees, (c) is not dependent on a specific unicast routing protocol, and (d) uses soft-state mechanisms to adapt to underlying network conditions and group dynamics. The robustness, flexibility, and scaling properties of this architecture make it well-suited to large heterogeneous internetworks     

Application versus network layer multicasting in ad hoc networks: the ALMA routing protocol

Application layer multicasting has emerged as an appealing alternative to network layer multicasting in wireline networks. Here, we examine the suitability of application layer multicast in ad hoc networks. To this effect, we propose a flexible receiver-driven overlay multicast protocol which we call Application Layer Multicast Algorithm (ALMA). ALMA constructs an overlay multicast tree in a dynamic, decentralized and incremental way. First, ALMA is receiver-driven: the member nodes find their connections according to their needs. Second, it is flexible, and thus, it can satisfy the performance goals and the needs of a wide range of applications. Third, it is highly adaptive: it reconfigures the tree in response to mobility or congestion. In addition, our protocol has the advantages of an application layer protocol: (a) simplicity of deployment, (b) independence from lower layer protocols, and (c) capability of exploiting features such as reliability and security that may be provided by the lower layers. Through extensive simulations, we show that ALMA performs favorably against the currently best application layer and network layer protocols. In more detail, we find that ALMA performs significantly better than ODMRP, a network layer, for small group sizes. We conclude that the application layer approach and ALMA seem very promising for ad hoc multicasting.     

Explicit Multicast Extension (Xcast+) for Efficient Multicast Packet Delivery

In this letter, we propose a new multicast scheme, named Xcast+, which is an extension of Explicit Multicast (Xcast) for an efficient delivery of multicast packets. The mechanism incorporates the host group model and a new control plane into existing Xcast, and not only does it provide the transparency of traditional multicast schemes to senders and receivers, but it also enhances the routing efficiency in networks. Since intermediate routers do not have to maintain any multicast states, it results in a more efficient and scalable mechanism to deliver multicast packets. Our simulation results show distinct performance improvements of our approach compared to Xcast, particularly as the number of receivers in a subnet increases.     

SDRAM: a SD channel-based multicast scheme on ATM networks for multimedia transmissions

Multicast delivery has become more and more important in modern multimedia applications. VoD and videoconferences are two examples. Multimedia integrates texts, audios, videos and still images in a variety of applications. The data in this media can be time critical in terms of maximum delay and delay jitter. In order to satisfy all these applications, the network needs to have an efficient multicasting mechanism using the true capability of ATM networks. In the native solution, a separate connection can be set up from the source to each group node, also called full connectivity. The full connectivity needs O(N/sup 2/) connections, where N is the number of nodes in a group. Instead, we can have one tree spanning all the participants. Multicast using a single shared tree has become the trend. In this paper, we propose a bi-directional multipoint-to-multipoint multicast scheme, a SD channel-based Multicast with Round-robin Access (SDRAM), for ATM networks, which uses a single tree for a multicast group consisting of multiple participants that are either senders, receivers, or a mix of both. We first discuss why the resequencer model will not be suitable for multimedia traffic, then propose the SDRAM scheme to solve the problems, and finally compare our scheme with the resequencer model through simulation. Results show the mean queuing delays and mean inter-PDU delays of our scheme are not sensitive to mean PDU size while the mean queuing delays and mean inter-PDU delays of the resequencer scheme are very sensitive to mean PDU size.     

动态QoS多播路由协议

本文主要研讨了具有QoS约束的动态多播路由问题.文中描述了一种适用于QoS多播路由的网络模型,提出了一种动态QoS多播路由协议(DQMRP),该协议能操作在单播路由协议的顶层,它只要求网络链路(或节点)的局部状态信息,不需要维护全局状态信息.DQMRP可有效地减少构造一棵多播树的开销,多播组成员可动态地加入／退出多播会晤.该协议可搜索多条可行树枝,并能选择一条最优(或近优)树枝将新成员连接到多播树.文中给出了DQMRP的正确性证明和复杂性分析,并通过仿真实验验证了该协议的可用性和有效性.     

An energy-efficient,distributed wireless multicast protocol based on concurrent CTS and <Emphasis Type="Italic">N</Emphasis><Superscript>2</Superscript> connectivity

Media acquisition process in wireless multicast requires that the sender obtains confirmation replies from a set of receivers. If replies are uncoordinated, the process can be much more time consuming than that of wireless unicast due to packet collisions. We propose a wireless multicast scheme that utilizes a novel concurrent Clear-To-Send (CTS) transmission method and a distributed multicast tree construction method. The concurrent CTS based MAC (Media Access Control) layer design can significantly reduce packet collisions and signaling overhead at the local cell level. Built on top of this new MAC layer protocol, we further propose a distributed multicast tree construction algorithm which grows the tree by maximizing the local multicast gain. The uniqueness of our algorithm is that the tree is constructed implicitly during the media access stage and the algorithm requires little additional message overhead. Extensive simulations are conducted to evaluate the performance of the proposed scheme. Our results indicate that the proposed scheme offers considerable improvement in multicast turnaround time and efficiency. The proposed scheme is also robust against network topology changes caused by node movements.     

Lightweight PIM—a new multicast routing protocol

Multicast holds out great promise to significantly reduce network load between the sender and a group of receivers by delivering a single data stream to many recipients. Protocol‐Independent Multicast (PIM) Sparse Mode and its variant PIM Source‐Specific Multicast (PIM SSM) are the most widely used IP multicast protocols. Protocols offer low latency data delivery capabilities with relatively high reliability and are characterized by large signaling overhead. This article presents a new multicast protocol, called Lightweight PIM (LPIM), tackling the main problem hindering widespread usage of IP multicast protocols, which is a large volume of signaling traffic. Given the existing usability of the PIM family protocols, a decision was made to base the new LPIM protocol on PIM SSM. The improvements used in LPIM lead to a considerable reduction of state data and signaling messages required by LPIM as compared with PIM SSM. Similar to its predecessor, LPIM is capable of handling large groups, although with significantly lower overhead. Copyright © 2012 John Wiley & Sons, Ltd.     

Protocol-independent multicast packet delivery improvement service for mobile Ad hoc networks

This paper addresses the issue of improving multicast packet delivery in mobile ad hoc networks and proposes an adaptive mechanism called Protocol-Independent Packet Delivery Improvement Service (PIDIS) to recover lost multicast packets. PIDIS provides its packet-delivery improvement services to any multicast routing protocol for mobile ad hoc networks by exploiting the mechanism of swarm intelligence to make intelligent decisions about where to fetch the lost multicast packets from. PIDIS is a gossip protocol, and nodes using PIDIS are only concerned with which neighbor nodes to gossip with to recover the most lost packets, rather than which member nodes to gossip with. Thus, it does not rely on membership information in a multicast scenario, which is often difficult to get. PIDIS employs the beneficial aspects of probabilistic routing and adapts well to mobility. PIDIS achieves probabilistic improvement in multicast packet delivery and, unlike other gossip-based schemes, does not need to maintain information about group members from which lost multicast packets are retrieved. Further, the operations of PIDIS do not rely on any underlying routing protocol or primitive, and can be incorporated into any ad hoc multicast routing protocol. We incorporated PIDIS over ODMRP [On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks, Kluwer Mobile Networks and Applications, 2000], and compared it against Anonymous Gossip (AG) [International Conference on Distributed Computing Systems (ICDCS 2001) Phoenix, Arizona, April 2001] implemented over ODMRP, and ODMRP itself. Our simulation results show that ODMRP + PIDIS is more efficient and performs better than ODMRP + AG and ODMRP in terms of multicast packet delivery, end-to-end delay, and MAC layer overheads. We attribute the better performance and lower MAC overheads of ODMRP + PIDIS to the efficient gossiping made possible by using the swarm intelligence techniques.     

Energy Efficient Adaptation of Multicast Protocols in Power Controlled Wireless Ad Hoc Networks

In this paper a methodology for adapting existing wireless ad hoc network protocols to power controlled networks is presented. Wireless nodes are assumed to have transmission power control with m discrete levels, and a clustering scheme is used in the adaptation to be energy efficient. Clusters are formed among the nodes in a distributed self-organized manner so that each node is a member of some cluster and within a cluster, each node can reach any other node with an appropriate power level. Each cluster has a designated head node which acts as forwarding agent for its members and these head nodes form a supernode topology. We adapt an ad hoc network multicast protocol by executing it on this supernode topology. Multicast data will move from the sender to its cluster head, then along the supernode topology according to the results of the chosen multicast protocol, and finally from the cluster head to receivers within their clusters. At every step, nodes use an appropriate power level j, 1jm, to reach all the intended recipients. For more balanced way of depleting energy in the network, nodes take turn to become cluster heads. We applied our technique to ODMRP and the experiment shows significant energy reduction.     

Approximate minimum-energy multicasting in wireless ad hoc networks

A wireless ad hoc network consists of mobile nodes that are equipped with energy-limited batteries. As mobile nodes are battery-operated, an important issue in such a network is to minimize the total power consumption for each operation. Multicast is one of fundamental operations in any modern telecommunication network including wireless ad hoc networks. Given a multicast request consisting of a source node and a set of destination nodes, the problem is to build a minimum-energy multicast tree for the request such that the total transmission power consumption in the tree is minimized. Since the problem in a symmetric wireless ad hoc network is NP-complete, we instead devise an approximation algorithm with provable approximation guarantee. The approximation of the solution delivered by the proposed algorithm is within a constant factor of the best-possible approximation achievable unless P = NP.